1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// HTTP server. See RFC 7230 through 7235.
package http
import (
"bufio"
"bytes"
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"log"
"math/rand"
"net"
"net/textproto"
"net/url"
urlpkg "net/url"
"os"
"path"
"runtime"
"sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"golang.org/x/net/http/httpguts"
)
// Errors used by the HTTP server.
var (
// ErrBodyNotAllowed is returned by ResponseWriter.Write calls
// when the HTTP method or response code does not permit a
// body.
ErrBodyNotAllowed = errors.New("http: request method or response status code does not allow body")
// ErrHijacked is returned by ResponseWriter.Write calls when
// the underlying connection has been hijacked using the
// Hijacker interface. A zero-byte write on a hijacked
// connection will return ErrHijacked without any other side
// effects.
ErrHijacked = errors.New("http: connection has been hijacked")
// ErrContentLength is returned by ResponseWriter.Write calls
// when a Handler set a Content-Length response header with a
// declared size and then attempted to write more bytes than
// declared.
ErrContentLength = errors.New("http: wrote more than the declared Content-Length")
// Deprecated: ErrWriteAfterFlush is no longer returned by
// anything in the net/http package. Callers should not
// compare errors against this variable.
ErrWriteAfterFlush = errors.New("unused")
)
// A Handler responds to an HTTP request.
//
// ServeHTTP should write reply headers and data to the ResponseWriter
// and then return. Returning signals that the request is finished; it
// is not valid to use the ResponseWriter or read from the
// Request.Body after or concurrently with the completion of the
// ServeHTTP call.
//
// Depending on the HTTP client software, HTTP protocol version, and
// any intermediaries between the client and the Go server, it may not
// be possible to read from the Request.Body after writing to the
// ResponseWriter. Cautious handlers should read the Request.Body
// first, and then reply.
//
// Except for reading the body, handlers should not modify the
// provided Request.
//
// If ServeHTTP panics, the server (the caller of ServeHTTP) assumes
// that the effect of the panic was isolated to the active request.
// It recovers the panic, logs a stack trace to the server error log,
// and either closes the network connection or sends an HTTP/2
// RST_STREAM, depending on the HTTP protocol. To abort a handler so
// the client sees an interrupted response but the server doesn't log
// an error, panic with the value ErrAbortHandler.
type Handler interface {
ServeHTTP(ResponseWriter, *Request)
}
// A ResponseWriter interface is used by an HTTP handler to
// construct an HTTP response.
//
// A ResponseWriter may not be used after the Handler.ServeHTTP method
// has returned.
type ResponseWriter interface {
// Header returns the header map that will be sent by
// WriteHeader. The Header map also is the mechanism with which
// Handlers can set HTTP trailers.
//
// Changing the header map after a call to WriteHeader (or
// Write) has no effect unless the modified headers are
// trailers.
//
// There are two ways to set Trailers. The preferred way is to
// predeclare in the headers which trailers you will later
// send by setting the "Trailer" header to the names of the
// trailer keys which will come later. In this case, those
// keys of the Header map are treated as if they were
// trailers. See the example. The second way, for trailer
// keys not known to the Handler until after the first Write,
// is to prefix the Header map keys with the TrailerPrefix
// constant value. See TrailerPrefix.
//
// To suppress automatic response headers (such as "Date"), set
// their value to nil.
Header() Header
// Write writes the data to the connection as part of an HTTP reply.
//
// If WriteHeader has not yet been called, Write calls
// WriteHeader(http.StatusOK) before writing the data. If the Header
// does not contain a Content-Type line, Write adds a Content-Type set
// to the result of passing the initial 512 bytes of written data to
// DetectContentType. Additionally, if the total size of all written
// data is under a few KB and there are no Flush calls, the
// Content-Length header is added automatically.
//
// Depending on the HTTP protocol version and the client, calling
// Write or WriteHeader may prevent future reads on the
// Request.Body. For HTTP/1.x requests, handlers should read any
// needed request body data before writing the response. Once the
// headers have been flushed (due to either an explicit Flusher.Flush
// call or writing enough data to trigger a flush), the request body
// may be unavailable. For HTTP/2 requests, the Go HTTP server permits
// handlers to continue to read the request body while concurrently
// writing the response. However, such behavior may not be supported
// by all HTTP/2 clients. Handlers should read before writing if
// possible to maximize compatibility.
Write([]byte) (int, error)
// WriteHeader sends an HTTP response header with the provided
// status code.
//
// If WriteHeader is not called explicitly, the first call to Write
// will trigger an implicit WriteHeader(http.StatusOK).
// Thus explicit calls to WriteHeader are mainly used to
// send error codes.
//
// The provided code must be a valid HTTP 1xx-5xx status code.
// Only one header may be written. Go does not currently
// support sending user-defined 1xx informational headers,
// with the exception of 100-continue response header that the
// Server sends automatically when the Request.Body is read.
WriteHeader(statusCode int)
}
// The Flusher interface is implemented by ResponseWriters that allow
// an HTTP handler to flush buffered data to the client.
//
// The default HTTP/1.x and HTTP/2 ResponseWriter implementations
// support Flusher, but ResponseWriter wrappers may not. Handlers
// should always test for this ability at runtime.
//
// Note that even for ResponseWriters that support Flush,
// if the client is connected through an HTTP proxy,
// the buffered data may not reach the client until the response
// completes.
type Flusher interface {
// Flush sends any buffered data to the client.
Flush()
}
// The Hijacker interface is implemented by ResponseWriters that allow
// an HTTP handler to take over the connection.
//
// The default ResponseWriter for HTTP/1.x connections supports
// Hijacker, but HTTP/2 connections intentionally do not.
// ResponseWriter wrappers may also not support Hijacker. Handlers
// should always test for this ability at runtime.
type Hijacker interface {
// Hijack lets the caller take over the connection.
// After a call to Hijack the HTTP server library
// will not do anything else with the connection.
//
// It becomes the caller's responsibility to manage
// and close the connection.
//
// The returned net.Conn may have read or write deadlines
// already set, depending on the configuration of the
// Server. It is the caller's responsibility to set
// or clear those deadlines as needed.
//
// The returned bufio.Reader may contain unprocessed buffered
// data from the client.
//
// After a call to Hijack, the original Request.Body must not
// be used. The original Request's Context remains valid and
// is not canceled until the Request's ServeHTTP method
// returns.
Hijack() (net.Conn, *bufio.ReadWriter, error)
}
// The CloseNotifier interface is implemented by ResponseWriters which
// allow detecting when the underlying connection has gone away.
//
// This mechanism can be used to cancel long operations on the server
// if the client has disconnected before the response is ready.
//
// Deprecated: the CloseNotifier interface predates Go's context package.
// New code should use Request.Context instead.
type CloseNotifier interface {
// CloseNotify returns a channel that receives at most a
// single value (true) when the client connection has gone
// away.
//
// CloseNotify may wait to notify until Request.Body has been
// fully read.
//
// After the Handler has returned, there is no guarantee
// that the channel receives a value.
//
// If the protocol is HTTP/1.1 and CloseNotify is called while
// processing an idempotent request (such a GET) while
// HTTP/1.1 pipelining is in use, the arrival of a subsequent
// pipelined request may cause a value to be sent on the
// returned channel. In practice HTTP/1.1 pipelining is not
// enabled in browsers and not seen often in the wild. If this
// is a problem, use HTTP/2 or only use CloseNotify on methods
// such as POST.
CloseNotify() <-chan bool
}
var (
// ServerContextKey is a context key. It can be used in HTTP
// handlers with Context.Value to access the server that
// started the handler. The associated value will be of
// type *Server.
ServerContextKey = &contextKey{"http-server"}
// LocalAddrContextKey is a context key. It can be used in
// HTTP handlers with Context.Value to access the local
// address the connection arrived on.
// The associated value will be of type net.Addr.
LocalAddrContextKey = &contextKey{"local-addr"}
)
// A conn represents the server side of an HTTP connection.
type conn struct {
// server is the server on which the connection arrived.
// Immutable; never nil.
server *Server
// cancelCtx cancels the connection-level context.
cancelCtx context.CancelFunc
// rwc is the underlying network connection.
// This is never wrapped by other types and is the value given out
// to CloseNotifier callers. It is usually of type *net.TCPConn or
// *tls.Conn.
rwc net.Conn
// remoteAddr is rwc.RemoteAddr().String(). It is not populated synchronously
// inside the Listener's Accept goroutine, as some implementations block.
// It is populated immediately inside the (*conn).serve goroutine.
// This is the value of a Handler's (*Request).RemoteAddr.
remoteAddr string
// tlsState is the TLS connection state when using TLS.
// nil means not TLS.
tlsState *tls.ConnectionState
// werr is set to the first write error to rwc.
// It is set via checkConnErrorWriter{w}, where bufw writes.
werr error
// r is bufr's read source. It's a wrapper around rwc that provides
// io.LimitedReader-style limiting (while reading request headers)
// and functionality to support CloseNotifier. See *connReader docs.
r *connReader
// bufr reads from r.
bufr *bufio.Reader
// bufw writes to checkConnErrorWriter{c}, which populates werr on error.
bufw *bufio.Writer
// lastMethod is the method of the most recent request
// on this connection, if any.
lastMethod string
curReq atomic.Value // of *response (which has a Request in it)
curState struct{ atomic uint64 } // packed (unixtime<<8|uint8(ConnState))
// mu guards hijackedv
mu sync.Mutex
// hijackedv is whether this connection has been hijacked
// by a Handler with the Hijacker interface.
// It is guarded by mu.
hijackedv bool
}
func (c *conn) hijacked() bool {
c.mu.Lock()
defer c.mu.Unlock()
return c.hijackedv
}
// c.mu must be held.
func (c *conn) hijackLocked() (rwc net.Conn, buf *bufio.ReadWriter, err error) {
if c.hijackedv {
return nil, nil, ErrHijacked
}
c.r.abortPendingRead()
c.hijackedv = true
rwc = c.rwc
rwc.SetDeadline(time.Time{})
buf = bufio.NewReadWriter(c.bufr, bufio.NewWriter(rwc))
if c.r.hasByte {
if _, err := c.bufr.Peek(c.bufr.Buffered() + 1); err != nil {
return nil, nil, fmt.Errorf("unexpected Peek failure reading buffered byte: %v", err)
}
}
c.setState(rwc, StateHijacked, runHooks)
return
}
// This should be >= 512 bytes for DetectContentType,
// but otherwise it's somewhat arbitrary.
const bufferBeforeChunkingSize = 2048
// chunkWriter writes to a response's conn buffer, and is the writer
// wrapped by the response.w buffered writer.
//
// chunkWriter also is responsible for finalizing the Header, including
// conditionally setting the Content-Type and setting a Content-Length
// in cases where the handler's final output is smaller than the buffer
// size. It also conditionally adds chunk headers, when in chunking mode.
//
// See the comment above (*response).Write for the entire write flow.
type chunkWriter struct {
res *response
// header is either nil or a deep clone of res.handlerHeader
// at the time of res.writeHeader, if res.writeHeader is
// called and extra buffering is being done to calculate
// Content-Type and/or Content-Length.
header Header
// wroteHeader tells whether the header's been written to "the
// wire" (or rather: w.conn.buf). this is unlike
// (*response).wroteHeader, which tells only whether it was
// logically written.
wroteHeader bool
// set by the writeHeader method:
chunking bool // using chunked transfer encoding for reply body
}
var (
crlf = []byte("\r\n")
colonSpace = []byte(": ")
)
func (cw *chunkWriter) Write(p []byte) (n int, err error) {
if !cw.wroteHeader {
cw.writeHeader(p)
}
if cw.res.req.Method == "HEAD" {
// Eat writes.
return len(p), nil
}
if cw.chunking {
_, err = fmt.Fprintf(cw.res.conn.bufw, "%x\r\n", len(p))
if err != nil {
cw.res.conn.rwc.Close()
return
}
}
n, err = cw.res.conn.bufw.Write(p)
if cw.chunking && err == nil {
_, err = cw.res.conn.bufw.Write(crlf)
}
if err != nil {
cw.res.conn.rwc.Close()
}
return
}
func (cw *chunkWriter) flush() {
if !cw.wroteHeader {
cw.writeHeader(nil)
}
cw.res.conn.bufw.Flush()
}
func (cw *chunkWriter) close() {
if !cw.wroteHeader {
cw.writeHeader(nil)
}
if cw.chunking {
bw := cw.res.conn.bufw // conn's bufio writer
// zero chunk to mark EOF
bw.WriteString("0\r\n")
if trailers := cw.res.finalTrailers(); trailers != nil {
trailers.Write(bw) // the writer handles noting errors
}
// final blank line after the trailers (whether
// present or not)
bw.WriteString("\r\n")
}
}
// A response represents the server side of an HTTP response.
type response struct {
conn *conn
req *Request // request for this response
reqBody io.ReadCloser
cancelCtx context.CancelFunc // when ServeHTTP exits
wroteHeader bool // reply header has been (logically) written
wroteContinue bool // 100 Continue response was written
wants10KeepAlive bool // HTTP/1.0 w/ Connection "keep-alive"
wantsClose bool // HTTP request has Connection "close"
// canWriteContinue is a boolean value accessed as an atomic int32
// that says whether or not a 100 Continue header can be written
// to the connection.
// writeContinueMu must be held while writing the header.
// These two fields together synchronize the body reader
// (the expectContinueReader, which wants to write 100 Continue)
// against the main writer.
canWriteContinue atomicBool
writeContinueMu sync.Mutex
w *bufio.Writer // buffers output in chunks to chunkWriter
cw chunkWriter
// handlerHeader is the Header that Handlers get access to,
// which may be retained and mutated even after WriteHeader.
// handlerHeader is copied into cw.header at WriteHeader
// time, and privately mutated thereafter.
handlerHeader Header
calledHeader bool // handler accessed handlerHeader via Header
written int64 // number of bytes written in body
contentLength int64 // explicitly-declared Content-Length; or -1
status int // status code passed to WriteHeader
// close connection after this reply. set on request and
// updated after response from handler if there's a
// "Connection: keep-alive" response header and a
// Content-Length.
closeAfterReply bool
// requestBodyLimitHit is set by requestTooLarge when
// maxBytesReader hits its max size. It is checked in
// WriteHeader, to make sure we don't consume the
// remaining request body to try to advance to the next HTTP
// request. Instead, when this is set, we stop reading
// subsequent requests on this connection and stop reading
// input from it.
requestBodyLimitHit bool
// trailers are the headers to be sent after the handler
// finishes writing the body. This field is initialized from
// the Trailer response header when the response header is
// written.
trailers []string
handlerDone atomicBool // set true when the handler exits
// Buffers for Date, Content-Length, and status code
dateBuf [len(TimeFormat)]byte
clenBuf [10]byte
statusBuf [3]byte
// closeNotifyCh is the channel returned by CloseNotify.
// TODO(bradfitz): this is currently (for Go 1.8) always
// non-nil. Make this lazily-created again as it used to be?
closeNotifyCh chan bool
didCloseNotify int32 // atomic (only 0->1 winner should send)
}
// TrailerPrefix is a magic prefix for ResponseWriter.Header map keys
// that, if present, signals that the map entry is actually for
// the response trailers, and not the response headers. The prefix
// is stripped after the ServeHTTP call finishes and the values are
// sent in the trailers.
//
// This mechanism is intended only for trailers that are not known
// prior to the headers being written. If the set of trailers is fixed
// or known before the header is written, the normal Go trailers mechanism
// is preferred:
// https://golang.org/pkg/net/http/#ResponseWriter
// https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
const TrailerPrefix = "Trailer:"
// finalTrailers is called after the Handler exits and returns a non-nil
// value if the Handler set any trailers.
func (w *response) finalTrailers() Header {
var t Header
for k, vv := range w.handlerHeader {
if strings.HasPrefix(k, TrailerPrefix) {
if t == nil {
t = make(Header)
}
t[strings.TrimPrefix(k, TrailerPrefix)] = vv
}
}
for _, k := range w.trailers {
if t == nil {
t = make(Header)
}
for _, v := range w.handlerHeader[k] {
t.Add(k, v)
}
}
return t
}
type atomicBool int32
func (b *atomicBool) isSet() bool { return atomic.LoadInt32((*int32)(b)) != 0 }
func (b *atomicBool) setTrue() { atomic.StoreInt32((*int32)(b), 1) }
func (b *atomicBool) setFalse() { atomic.StoreInt32((*int32)(b), 0) }
// declareTrailer is called for each Trailer header when the
// response header is written. It notes that a header will need to be
// written in the trailers at the end of the response.
func (w *response) declareTrailer(k string) {
k = CanonicalHeaderKey(k)
if !httpguts.ValidTrailerHeader(k) {
// Forbidden by RFC 7230, section 4.1.2
return
}
w.trailers = append(w.trailers, k)
}
// requestTooLarge is called by maxBytesReader when too much input has
// been read from the client.
func (w *response) requestTooLarge() {
w.closeAfterReply = true
w.requestBodyLimitHit = true
if !w.wroteHeader {
w.Header().Set("Connection", "close")
}
}
// needsSniff reports whether a Content-Type still needs to be sniffed.
func (w *response) needsSniff() bool {
_, haveType := w.handlerHeader["Content-Type"]
return !w.cw.wroteHeader && !haveType && w.written < sniffLen
}
// writerOnly hides an io.Writer value's optional ReadFrom method
// from io.Copy.
type writerOnly struct {
io.Writer
}
// ReadFrom is here to optimize copying from an *os.File regular file
// to a *net.TCPConn with sendfile, or from a supported src type such
// as a *net.TCPConn on Linux with splice.
func (w *response) ReadFrom(src io.Reader) (n int64, err error) {
bufp := copyBufPool.Get().(*[]byte)
buf := *bufp
defer copyBufPool.Put(bufp)
// Our underlying w.conn.rwc is usually a *TCPConn (with its
// own ReadFrom method). If not, just fall back to the normal
// copy method.
rf, ok := w.conn.rwc.(io.ReaderFrom)
if !ok {
return io.CopyBuffer(writerOnly{w}, src, buf)
}
// Copy the first sniffLen bytes before switching to ReadFrom.
// This ensures we don't start writing the response before the
// source is available (see golang.org/issue/5660) and provides
// enough bytes to perform Content-Type sniffing when required.
if !w.cw.wroteHeader {
n0, err := io.CopyBuffer(writerOnly{w}, io.LimitReader(src, sniffLen), buf)
n += n0
if err != nil || n0 < sniffLen {
return n, err
}
}
w.w.Flush() // get rid of any previous writes
w.cw.flush() // make sure Header is written; flush data to rwc
// Now that cw has been flushed, its chunking field is guaranteed initialized.
if !w.cw.chunking && w.bodyAllowed() {
n0, err := rf.ReadFrom(src)
n += n0
w.written += n0
return n, err
}
n0, err := io.CopyBuffer(writerOnly{w}, src, buf)
n += n0
return n, err
}
// debugServerConnections controls whether all server connections are wrapped
// with a verbose logging wrapper.
const debugServerConnections = false
// Create new connection from rwc.
func (srv *Server) newConn(rwc net.Conn) *conn {
c := &conn{
server: srv,
rwc: rwc,
}
if debugServerConnections {
c.rwc = newLoggingConn("server", c.rwc)
}
return c
}
type readResult struct {
_ incomparable
n int
err error
b byte // byte read, if n == 1
}
// connReader is the io.Reader wrapper used by *conn. It combines a
// selectively-activated io.LimitedReader (to bound request header
// read sizes) with support for selectively keeping an io.Reader.Read
// call blocked in a background goroutine to wait for activity and
// trigger a CloseNotifier channel.
type connReader struct {
conn *conn
mu sync.Mutex // guards following
hasByte bool
byteBuf [1]byte
cond *sync.Cond
inRead bool
aborted bool // set true before conn.rwc deadline is set to past
remain int64 // bytes remaining
}
func (cr *connReader) lock() {
cr.mu.Lock()
if cr.cond == nil {
cr.cond = sync.NewCond(&cr.mu)
}
}
func (cr *connReader) unlock() { cr.mu.Unlock() }
func (cr *connReader) startBackgroundRead() {
cr.lock()
defer cr.unlock()
if cr.inRead {
panic("invalid concurrent Body.Read call")
}
if cr.hasByte {
return
}
cr.inRead = true
cr.conn.rwc.SetReadDeadline(time.Time{})
go cr.backgroundRead()
}
func (cr *connReader) backgroundRead() {
n, err := cr.conn.rwc.Read(cr.byteBuf[:])
cr.lock()
if n == 1 {
cr.hasByte = true
// We were past the end of the previous request's body already
// (since we wouldn't be in a background read otherwise), so
// this is a pipelined HTTP request. Prior to Go 1.11 we used to
// send on the CloseNotify channel and cancel the context here,
// but the behavior was documented as only "may", and we only
// did that because that's how CloseNotify accidentally behaved
// in very early Go releases prior to context support. Once we
// added context support, people used a Handler's
// Request.Context() and passed it along. Having that context
// cancel on pipelined HTTP requests caused problems.
// Fortunately, almost nothing uses HTTP/1.x pipelining.
// Unfortunately, apt-get does, or sometimes does.
// New Go 1.11 behavior: don't fire CloseNotify or cancel
// contexts on pipelined requests. Shouldn't affect people, but
// fixes cases like Issue 23921. This does mean that a client
// closing their TCP connection after sending a pipelined
// request won't cancel the context, but we'll catch that on any
// write failure (in checkConnErrorWriter.Write).
// If the server never writes, yes, there are still contrived
// server & client behaviors where this fails to ever cancel the
// context, but that's kinda why HTTP/1.x pipelining died
// anyway.
}
if ne, ok := err.(net.Error); ok && cr.aborted && ne.Timeout() {
// Ignore this error. It's the expected error from
// another goroutine calling abortPendingRead.
} else if err != nil {
cr.handleReadError(err)
}
cr.aborted = false
cr.inRead = false
cr.unlock()
cr.cond.Broadcast()
}
func (cr *connReader) abortPendingRead() {
cr.lock()
defer cr.unlock()
if !cr.inRead {
return
}
cr.aborted = true
cr.conn.rwc.SetReadDeadline(aLongTimeAgo)
for cr.inRead {
cr.cond.Wait()
}
cr.conn.rwc.SetReadDeadline(time.Time{})
}
func (cr *connReader) setReadLimit(remain int64) { cr.remain = remain }
func (cr *connReader) setInfiniteReadLimit() { cr.remain = maxInt64 }
func (cr *connReader) hitReadLimit() bool { return cr.remain <= 0 }
// handleReadError is called whenever a Read from the client returns a
// non-nil error.
//
// The provided non-nil err is almost always io.EOF or a "use of
// closed network connection". In any case, the error is not
// particularly interesting, except perhaps for debugging during
// development. Any error means the connection is dead and we should
// down its context.
//
// It may be called from multiple goroutines.
func (cr *connReader) handleReadError(_ error) {
cr.conn.cancelCtx()
cr.closeNotify()
}
// may be called from multiple goroutines.
func (cr *connReader) closeNotify() {
res, _ := cr.conn.curReq.Load().(*response)
if res != nil && atomic.CompareAndSwapInt32(&res.didCloseNotify, 0, 1) {
res.closeNotifyCh <- true
}
}
func (cr *connReader) Read(p []byte) (n int, err error) {
cr.lock()
if cr.inRead {
cr.unlock()
if cr.conn.hijacked() {
panic("invalid Body.Read call. After hijacked, the original Request must not be used")
}
panic("invalid concurrent Body.Read call")
}
if cr.hitReadLimit() {
cr.unlock()
return 0, io.EOF
}
if len(p) == 0 {
cr.unlock()
return 0, nil
}
if int64(len(p)) > cr.remain {
p = p[:cr.remain]
}
if cr.hasByte {
p[0] = cr.byteBuf[0]
cr.hasByte = false
cr.unlock()
return 1, nil
}
cr.inRead = true
cr.unlock()
n, err = cr.conn.rwc.Read(p)
cr.lock()
cr.inRead = false
if err != nil {
cr.handleReadError(err)
}
cr.remain -= int64(n)
cr.unlock()
cr.cond.Broadcast()
return n, err
}
var (
bufioReaderPool sync.Pool
bufioWriter2kPool sync.Pool
bufioWriter4kPool sync.Pool
)
var copyBufPool = sync.Pool{
New: func() interface{} {
b := make([]byte, 32*1024)
return &b
},
}
func bufioWriterPool(size int) *sync.Pool {
switch size {
case 2 << 10:
return &bufioWriter2kPool
case 4 << 10:
return &bufioWriter4kPool
}
return nil
}
func newBufioReader(r io.Reader) *bufio.Reader {
if v := bufioReaderPool.Get(); v != nil {
br := v.(*bufio.Reader)
br.Reset(r)
return br
}
// Note: if this reader size is ever changed, update
// TestHandlerBodyClose's assumptions.
return bufio.NewReader(r)
}
func putBufioReader(br *bufio.Reader) {
br.Reset(nil)
bufioReaderPool.Put(br)
}
func newBufioWriterSize(w io.Writer, size int) *bufio.Writer {
pool := bufioWriterPool(size)
if pool != nil {
if v := pool.Get(); v != nil {
bw := v.(*bufio.Writer)
bw.Reset(w)
return bw
}
}
return bufio.NewWriterSize(w, size)
}
func putBufioWriter(bw *bufio.Writer) {
bw.Reset(nil)
if pool := bufioWriterPool(bw.Available()); pool != nil {
pool.Put(bw)
}
}
// DefaultMaxHeaderBytes is the maximum permitted size of the headers
// in an HTTP request.
// This can be overridden by setting Server.MaxHeaderBytes.
const DefaultMaxHeaderBytes = 1 << 20 // 1 MB
func (srv *Server) maxHeaderBytes() int {
if srv.MaxHeaderBytes > 0 {
return srv.MaxHeaderBytes
}
return DefaultMaxHeaderBytes
}
func (srv *Server) initialReadLimitSize() int64 {
return int64(srv.maxHeaderBytes()) + 4096 // bufio slop
}
// wrapper around io.ReadCloser which on first read, sends an
// HTTP/1.1 100 Continue header
type expectContinueReader struct {
resp *response
readCloser io.ReadCloser
closed atomicBool
sawEOF atomicBool
}
func (ecr *expectContinueReader) Read(p []byte) (n int, err error) {
if ecr.closed.isSet() {
return 0, ErrBodyReadAfterClose
}
w := ecr.resp
if !w.wroteContinue && w.canWriteContinue.isSet() && !w.conn.hijacked() {
w.wroteContinue = true
w.writeContinueMu.Lock()
if w.canWriteContinue.isSet() {
w.conn.bufw.WriteString("HTTP/1.1 100 Continue\r\n\r\n")
w.conn.bufw.Flush()
w.canWriteContinue.setFalse()
}
w.writeContinueMu.Unlock()
}
n, err = ecr.readCloser.Read(p)
if err == io.EOF {
ecr.sawEOF.setTrue()
}
return
}
func (ecr *expectContinueReader) Close() error {
ecr.closed.setTrue()
return ecr.readCloser.Close()
}
// TimeFormat is the time format to use when generating times in HTTP
// headers. It is like time.RFC1123 but hard-codes GMT as the time
// zone. The time being formatted must be in UTC for Format to
// generate the correct format.
//
// For parsing this time format, see ParseTime.
const TimeFormat = "Mon, 02 Jan 2006 15:04:05 GMT"
// appendTime is a non-allocating version of []byte(t.UTC().Format(TimeFormat))
func appendTime(b []byte, t time.Time) []byte {
const days = "SunMonTueWedThuFriSat"
const months = "JanFebMarAprMayJunJulAugSepOctNovDec"
t = t.UTC()
yy, mm, dd := t.Date()
hh, mn, ss := t.Clock()
day := days[3*t.Weekday():]
mon := months[3*(mm-1):]
return append(b,
day[0], day[1], day[2], ',', ' ',
byte('0'+dd/10), byte('0'+dd%10), ' ',
mon[0], mon[1], mon[2], ' ',
byte('0'+yy/1000), byte('0'+(yy/100)%10), byte('0'+(yy/10)%10), byte('0'+yy%10), ' ',
byte('0'+hh/10), byte('0'+hh%10), ':',
byte('0'+mn/10), byte('0'+mn%10), ':',
byte('0'+ss/10), byte('0'+ss%10), ' ',
'G', 'M', 'T')
}
var errTooLarge = errors.New("http: request too large")
// Read next request from connection.
func (c *conn) readRequest(ctx context.Context) (w *response, err error) {
if c.hijacked() {
return nil, ErrHijacked
}
var (
wholeReqDeadline time.Time // or zero if none
hdrDeadline time.Time // or zero if none
)
t0 := time.Now()
if d := c.server.readHeaderTimeout(); d > 0 {
hdrDeadline = t0.Add(d)
}
if d := c.server.ReadTimeout; d > 0 {
wholeReqDeadline = t0.Add(d)
}
c.rwc.SetReadDeadline(hdrDeadline)
if d := c.server.WriteTimeout; d > 0 {
defer func() {
c.rwc.SetWriteDeadline(time.Now().Add(d))
}()
}
c.r.setReadLimit(c.server.initialReadLimitSize())
if c.lastMethod == "POST" {
// RFC 7230 section 3 tolerance for old buggy clients.
peek, _ := c.bufr.Peek(4) // ReadRequest will get err below
c.bufr.Discard(numLeadingCRorLF(peek))
}
req, err := readRequest(c.bufr)
if err != nil {
if c.r.hitReadLimit() {
return nil, errTooLarge
}
return nil, err
}
if !http1ServerSupportsRequest(req) {
return nil, statusError{StatusHTTPVersionNotSupported, "unsupported protocol version"}
}
c.lastMethod = req.Method
c.r.setInfiniteReadLimit()
hosts, haveHost := req.Header["Host"]
isH2Upgrade := req.isH2Upgrade()
if req.ProtoAtLeast(1, 1) && (!haveHost || len(hosts) == 0) && !isH2Upgrade && req.Method != "CONNECT" {
return nil, badRequestError("missing required Host header")
}
if len(hosts) == 1 && !httpguts.ValidHostHeader(hosts[0]) {
return nil, badRequestError("malformed Host header")
}
for k, vv := range req.Header {
if !httpguts.ValidHeaderFieldName(k) {
return nil, badRequestError("invalid header name")
}
for _, v := range vv {
if !httpguts.ValidHeaderFieldValue(v) {
return nil, badRequestError("invalid header value")
}
}
}
delete(req.Header, "Host")
ctx, cancelCtx := context.WithCancel(ctx)
req.ctx = ctx
req.RemoteAddr = c.remoteAddr
req.TLS = c.tlsState
if body, ok := req.Body.(*body); ok {
body.doEarlyClose = true
}
// Adjust the read deadline if necessary.
if !hdrDeadline.Equal(wholeReqDeadline) {
c.rwc.SetReadDeadline(wholeReqDeadline)
}
w = &response{
conn: c,
cancelCtx: cancelCtx,
req: req,
reqBody: req.Body,
handlerHeader: make(Header),
contentLength: -1,
closeNotifyCh: make(chan bool, 1),
// We populate these ahead of time so we're not
// reading from req.Header after their Handler starts
// and maybe mutates it (Issue 14940)
wants10KeepAlive: req.wantsHttp10KeepAlive(),
wantsClose: req.wantsClose(),
}
if isH2Upgrade {
w.closeAfterReply = true
}
w.cw.res = w
w.w = newBufioWriterSize(&w.cw, bufferBeforeChunkingSize)
return w, nil
}
// http1ServerSupportsRequest reports whether Go's HTTP/1.x server
// supports the given request.
func http1ServerSupportsRequest(req *Request) bool {
if req.ProtoMajor == 1 {
return true
}
// Accept "PRI * HTTP/2.0" upgrade requests, so Handlers can
// wire up their own HTTP/2 upgrades.
if req.ProtoMajor == 2 && req.ProtoMinor == 0 &&
req.Method == "PRI" && req.RequestURI == "*" {
return true
}
// Reject HTTP/0.x, and all other HTTP/2+ requests (which
// aren't encoded in ASCII anyway).
return false
}
func (w *response) Header() Header {
if w.cw.header == nil && w.wroteHeader && !w.cw.wroteHeader {
// Accessing the header between logically writing it
// and physically writing it means we need to allocate
// a clone to snapshot the logically written state.
w.cw.header = w.handlerHeader.Clone()
}
w.calledHeader = true
return w.handlerHeader
}
// maxPostHandlerReadBytes is the max number of Request.Body bytes not
// consumed by a handler that the server will read from the client
// in order to keep a connection alive. If there are more bytes than
// this then the server to be paranoid instead sends a "Connection:
// close" response.
//
// This number is approximately what a typical machine's TCP buffer
// size is anyway. (if we have the bytes on the machine, we might as
// well read them)
const maxPostHandlerReadBytes = 256 << 10
func checkWriteHeaderCode(code int) {
// Issue 22880: require valid WriteHeader status codes.
// For now we only enforce that it's three digits.
// In the future we might block things over 599 (600 and above aren't defined
// at https://httpwg.org/specs/rfc7231.html#status.codes)
// and we might block under 200 (once we have more mature 1xx support).
// But for now any three digits.
//
// We used to send "HTTP/1.1 000 0" on the wire in responses but there's
// no equivalent bogus thing we can realistically send in HTTP/2,
// so we'll consistently panic instead and help people find their bugs
// early. (We can't return an error from WriteHeader even if we wanted to.)
if code < 100 || code > 999 {
panic(fmt.Sprintf("invalid WriteHeader code %v", code))
}
}
// relevantCaller searches the call stack for the first function outside of net/http.
// The purpose of this function is to provide more helpful error messages.
func relevantCaller() runtime.Frame {
pc := make([]uintptr, 16)
n := runtime.Callers(1, pc)
frames := runtime.CallersFrames(pc[:n])
prefix1 := "net/http."
prefix2 := "net/http."
if runtime.Compiler == "gccgo" {
prefix2 = "http."
}
var frame runtime.Frame
for {
frame, more := frames.Next()
if !strings.HasPrefix(frame.Function, prefix1) && !strings.HasPrefix(frame.Function, prefix2) {
return frame
}
if !more {
break
}
}
return frame
}
func (w *response) WriteHeader(code int) {
if w.conn.hijacked() {
caller := relevantCaller()
w.conn.server.logf("http: response.WriteHeader on hijacked connection from %s (%s:%d)", caller.Function, path.Base(caller.File), caller.Line)
return
}
if w.wroteHeader {
caller := relevantCaller()
w.conn.server.logf("http: superfluous response.WriteHeader call from %s (%s:%d)", caller.Function, path.Base(caller.File), caller.Line)
return
}
checkWriteHeaderCode(code)
w.wroteHeader = true
w.status = code
if w.calledHeader && w.cw.header == nil {
w.cw.header = w.handlerHeader.Clone()
}
if cl := w.handlerHeader.get("Content-Length"); cl != "" {
v, err := strconv.ParseInt(cl, 10, 64)
if err == nil && v >= 0 {
w.contentLength = v
} else {
w.conn.server.logf("http: invalid Content-Length of %q", cl)
w.handlerHeader.Del("Content-Length")
}
}
}
// extraHeader is the set of headers sometimes added by chunkWriter.writeHeader.
// This type is used to avoid extra allocations from cloning and/or populating
// the response Header map and all its 1-element slices.
type extraHeader struct {
contentType string
connection string
transferEncoding string
date []byte // written if not nil
contentLength []byte // written if not nil
}
// Sorted the same as extraHeader.Write's loop.
var extraHeaderKeys = [][]byte{
[]byte("Content-Type"),
[]byte("Connection"),
[]byte("Transfer-Encoding"),
}
var (
headerContentLength = []byte("Content-Length: ")
headerDate = []byte("Date: ")
)
// Write writes the headers described in h to w.
//
// This method has a value receiver, despite the somewhat large size
// of h, because it prevents an allocation. The escape analysis isn't
// smart enough to realize this function doesn't mutate h.
func (h extraHeader) Write(w *bufio.Writer) {
if h.date != nil {
w.Write(headerDate)
w.Write(h.date)
w.Write(crlf)
}
if h.contentLength != nil {
w.Write(headerContentLength)
w.Write(h.contentLength)
w.Write(crlf)
}
for i, v := range []string{h.contentType, h.connection, h.transferEncoding} {
if v != "" {
w.Write(extraHeaderKeys[i])
w.Write(colonSpace)
w.WriteString(v)
w.Write(crlf)
}
}
}
// writeHeader finalizes the header sent to the client and writes it
// to cw.res.conn.bufw.
//
// p is not written by writeHeader, but is the first chunk of the body
// that will be written. It is sniffed for a Content-Type if none is
// set explicitly. It's also used to set the Content-Length, if the
// total body size was small and the handler has already finished
// running.
func (cw *chunkWriter) writeHeader(p []byte) {
if cw.wroteHeader {
return
}
cw.wroteHeader = true
w := cw.res
keepAlivesEnabled := w.conn.server.doKeepAlives()
isHEAD := w.req.Method == "HEAD"
// header is written out to w.conn.buf below. Depending on the
// state of the handler, we either own the map or not. If we
// don't own it, the exclude map is created lazily for
// WriteSubset to remove headers. The setHeader struct holds
// headers we need to add.
header := cw.header
owned := header != nil
if !owned {
header = w.handlerHeader
}
var excludeHeader map[string]bool
delHeader := func(key string) {
if owned {
header.Del(key)
return
}
if _, ok := header[key]; !ok {
return
}
if excludeHeader == nil {
excludeHeader = make(map[string]bool)
}
excludeHeader[key] = true
}
var setHeader extraHeader
// Don't write out the fake "Trailer:foo" keys. See TrailerPrefix.
trailers := false
for k := range cw.header {
if strings.HasPrefix(k, TrailerPrefix) {
if excludeHeader == nil {
excludeHeader = make(map[string]bool)
}
excludeHeader[k] = true
trailers = true
}
}
for _, v := range cw.header["Trailer"] {
trailers = true
foreachHeaderElement(v, cw.res.declareTrailer)
}
te := header.get("Transfer-Encoding")
hasTE := te != ""
// If the handler is done but never sent a Content-Length
// response header and this is our first (and last) write, set
// it, even to zero. This helps HTTP/1.0 clients keep their
// "keep-alive" connections alive.
// Exceptions: 304/204/1xx responses never get Content-Length, and if
// it was a HEAD request, we don't know the difference between
// 0 actual bytes and 0 bytes because the handler noticed it
// was a HEAD request and chose not to write anything. So for
// HEAD, the handler should either write the Content-Length or
// write non-zero bytes. If it's actually 0 bytes and the
// handler never looked at the Request.Method, we just don't
// send a Content-Length header.
// Further, we don't send an automatic Content-Length if they
// set a Transfer-Encoding, because they're generally incompatible.
if w.handlerDone.isSet() && !trailers && !hasTE && bodyAllowedForStatus(w.status) && header.get("Content-Length") == "" && (!isHEAD || len(p) > 0) {
w.contentLength = int64(len(p))
setHeader.contentLength = strconv.AppendInt(cw.res.clenBuf[:0], int64(len(p)), 10)
}
// If this was an HTTP/1.0 request with keep-alive and we sent a
// Content-Length back, we can make this a keep-alive response ...
if w.wants10KeepAlive && keepAlivesEnabled {
sentLength := header.get("Content-Length") != ""
if sentLength && header.get("Connection") == "keep-alive" {
w.closeAfterReply = false
}
}
// Check for an explicit (and valid) Content-Length header.
hasCL := w.contentLength != -1
if w.wants10KeepAlive && (isHEAD || hasCL || !bodyAllowedForStatus(w.status)) {
_, connectionHeaderSet := header["Connection"]
if !connectionHeaderSet {
setHeader.connection = "keep-alive"
}
} else if !w.req.ProtoAtLeast(1, 1) || w.wantsClose {
w.closeAfterReply = true
}
if header.get("Connection") == "close" || !keepAlivesEnabled {
w.closeAfterReply = true
}
// If the client wanted a 100-continue but we never sent it to
// them (or, more strictly: we never finished reading their
// request body), don't reuse this connection because it's now
// in an unknown state: we might be sending this response at
// the same time the client is now sending its request body
// after a timeout. (Some HTTP clients send Expect:
// 100-continue but knowing that some servers don't support
// it, the clients set a timer and send the body later anyway)
// If we haven't seen EOF, we can't skip over the unread body
// because we don't know if the next bytes on the wire will be
// the body-following-the-timer or the subsequent request.
// See Issue 11549.
if ecr, ok := w.req.Body.(*expectContinueReader); ok && !ecr.sawEOF.isSet() {
w.closeAfterReply = true
}
// Per RFC 2616, we should consume the request body before
// replying, if the handler hasn't already done so. But we
// don't want to do an unbounded amount of reading here for
// DoS reasons, so we only try up to a threshold.
// TODO(bradfitz): where does RFC 2616 say that? See Issue 15527
// about HTTP/1.x Handlers concurrently reading and writing, like
// HTTP/2 handlers can do. Maybe this code should be relaxed?
if w.req.ContentLength != 0 && !w.closeAfterReply {
var discard, tooBig bool
switch bdy := w.req.Body.(type) {
case *expectContinueReader:
if bdy.resp.wroteContinue {
discard = true
}
case *body:
bdy.mu.Lock()
switch {
case bdy.closed:
if !bdy.sawEOF {
// Body was closed in handler with non-EOF error.
w.closeAfterReply = true
}
case bdy.unreadDataSizeLocked() >= maxPostHandlerReadBytes:
tooBig = true
default:
discard = true
}
bdy.mu.Unlock()
default:
discard = true
}
if discard {
_, err := io.CopyN(io.Discard, w.reqBody, maxPostHandlerReadBytes+1)
switch err {
case nil:
// There must be even more data left over.
tooBig = true
case ErrBodyReadAfterClose:
// Body was already consumed and closed.
case io.EOF:
// The remaining body was just consumed, close it.
err = w.reqBody.Close()
if err != nil {
w.closeAfterReply = true
}
default:
// Some other kind of error occurred, like a read timeout, or
// corrupt chunked encoding. In any case, whatever remains
// on the wire must not be parsed as another HTTP request.
w.closeAfterReply = true
}
}
if tooBig {
w.requestTooLarge()
delHeader("Connection")
setHeader.connection = "close"
}
}
code := w.status
if bodyAllowedForStatus(code) {
// If no content type, apply sniffing algorithm to body.
_, haveType := header["Content-Type"]
// If the Content-Encoding was set and is non-blank,
// we shouldn't sniff the body. See Issue 31753.
ce := header.Get("Content-Encoding")
hasCE := len(ce) > 0
if !hasCE && !haveType && !hasTE && len(p) > 0 {
setHeader.contentType = DetectContentType(p)
}
} else {
for _, k := range suppressedHeaders(code) {
delHeader(k)
}
}
if !header.has("Date") {
setHeader.date = appendTime(cw.res.dateBuf[:0], time.Now())
}
if hasCL && hasTE && te != "identity" {
// TODO: return an error if WriteHeader gets a return parameter
// For now just ignore the Content-Length.
w.conn.server.logf("http: WriteHeader called with both Transfer-Encoding of %q and a Content-Length of %d",
te, w.contentLength)
delHeader("Content-Length")
hasCL = false
}
if w.req.Method == "HEAD" || !bodyAllowedForStatus(code) {
// do nothing
} else if code == StatusNoContent {
delHeader("Transfer-Encoding")
} else if hasCL {
delHeader("Transfer-Encoding")
} else if w.req.ProtoAtLeast(1, 1) {
// HTTP/1.1 or greater: Transfer-Encoding has been set to identity, and no
// content-length has been provided. The connection must be closed after the
// reply is written, and no chunking is to be done. This is the setup
// recommended in the Server-Sent Events candidate recommendation 11,
// section 8.
if hasTE && te == "identity" {
cw.chunking = false
w.closeAfterReply = true
} else {
// HTTP/1.1 or greater: use chunked transfer encoding
// to avoid closing the connection at EOF.
cw.chunking = true
setHeader.transferEncoding = "chunked"
if hasTE && te == "chunked" {
// We will send the chunked Transfer-Encoding header later.
delHeader("Transfer-Encoding")
}
}
} else {
// HTTP version < 1.1: cannot do chunked transfer
// encoding and we don't know the Content-Length so
// signal EOF by closing connection.
w.closeAfterReply = true
delHeader("Transfer-Encoding") // in case already set
}
// Cannot use Content-Length with non-identity Transfer-Encoding.
if cw.chunking {
delHeader("Content-Length")
}
if !w.req.ProtoAtLeast(1, 0) {
return
}
// Only override the Connection header if it is not a successful
// protocol switch response and if KeepAlives are not enabled.
// See https://golang.org/issue/36381.
delConnectionHeader := w.closeAfterReply &&
(!keepAlivesEnabled || !hasToken(cw.header.get("Connection"), "close")) &&
!isProtocolSwitchResponse(w.status, header)
if delConnectionHeader {
delHeader("Connection")
if w.req.ProtoAtLeast(1, 1) {
setHeader.connection = "close"
}
}
writeStatusLine(w.conn.bufw, w.req.ProtoAtLeast(1, 1), code, w.statusBuf[:])
cw.header.WriteSubset(w.conn.bufw, excludeHeader)
setHeader.Write(w.conn.bufw)
w.conn.bufw.Write(crlf)
}
// foreachHeaderElement splits v according to the "#rule" construction
// in RFC 7230 section 7 and calls fn for each non-empty element.
func foreachHeaderElement(v string, fn func(string)) {
v = textproto.TrimString(v)
if v == "" {
return
}
if !strings.Contains(v, ",") {
fn(v)
return
}
for _, f := range strings.Split(v, ",") {
if f = textproto.TrimString(f); f != "" {
fn(f)
}
}
}
// writeStatusLine writes an HTTP/1.x Status-Line (RFC 7230 Section 3.1.2)
// to bw. is11 is whether the HTTP request is HTTP/1.1. false means HTTP/1.0.
// code is the response status code.
// scratch is an optional scratch buffer. If it has at least capacity 3, it's used.
func writeStatusLine(bw *bufio.Writer, is11 bool, code int, scratch []byte) {
if is11 {
bw.WriteString("HTTP/1.1 ")
} else {
bw.WriteString("HTTP/1.0 ")
}
if text, ok := statusText[code]; ok {
bw.Write(strconv.AppendInt(scratch[:0], int64(code), 10))
bw.WriteByte(' ')
bw.WriteString(text)
bw.WriteString("\r\n")
} else {
// don't worry about performance
fmt.Fprintf(bw, "%03d status code %d\r\n", code, code)
}
}
// bodyAllowed reports whether a Write is allowed for this response type.
// It's illegal to call this before the header has been flushed.
func (w *response) bodyAllowed() bool {
if !w.wroteHeader {
panic("")
}
return bodyAllowedForStatus(w.status)
}
// The Life Of A Write is like this:
//
// Handler starts. No header has been sent. The handler can either
// write a header, or just start writing. Writing before sending a header
// sends an implicitly empty 200 OK header.
//
// If the handler didn't declare a Content-Length up front, we either
// go into chunking mode or, if the handler finishes running before
// the chunking buffer size, we compute a Content-Length and send that
// in the header instead.
//
// Likewise, if the handler didn't set a Content-Type, we sniff that
// from the initial chunk of output.
//
// The Writers are wired together like:
//
// 1. *response (the ResponseWriter) ->
// 2. (*response).w, a *bufio.Writer of bufferBeforeChunkingSize bytes ->
// 3. chunkWriter.Writer (whose writeHeader finalizes Content-Length/Type)
// and which writes the chunk headers, if needed ->
// 4. conn.bufw, a *bufio.Writer of default (4kB) bytes, writing to ->
// 5. checkConnErrorWriter{c}, which notes any non-nil error on Write
// and populates c.werr with it if so, but otherwise writes to ->
// 6. the rwc, the net.Conn.
//
// TODO(bradfitz): short-circuit some of the buffering when the
// initial header contains both a Content-Type and Content-Length.
// Also short-circuit in (1) when the header's been sent and not in
// chunking mode, writing directly to (4) instead, if (2) has no
// buffered data. More generally, we could short-circuit from (1) to
// (3) even in chunking mode if the write size from (1) is over some
// threshold and nothing is in (2). The answer might be mostly making
// bufferBeforeChunkingSize smaller and having bufio's fast-paths deal
// with this instead.
func (w *response) Write(data []byte) (n int, err error) {
return w.write(len(data), data, "")
}
func (w *response) WriteString(data string) (n int, err error) {
return w.write(len(data), nil, data)
}
// either dataB or dataS is non-zero.
func (w *response) write(lenData int, dataB []byte, dataS string) (n int, err error) {
if w.conn.hijacked() {
if lenData > 0 {
caller := relevantCaller()
w.conn.server.logf("http: response.Write on hijacked connection from %s (%s:%d)", caller.Function, path.Base(caller.File), caller.Line)
}
return 0, ErrHijacked
}
if w.canWriteContinue.isSet() {
// Body reader wants to write 100 Continue but hasn't yet.
// Tell it not to. The store must be done while holding the lock
// because the lock makes sure that there is not an active write
// this very moment.
w.writeContinueMu.Lock()
w.canWriteContinue.setFalse()
w.writeContinueMu.Unlock()
}
if !w.wroteHeader {
w.WriteHeader(StatusOK)
}
if lenData == 0 {
return 0, nil
}
if !w.bodyAllowed() {
return 0, ErrBodyNotAllowed
}
w.written += int64(lenData) // ignoring errors, for errorKludge
if w.contentLength != -1 && w.written > w.contentLength {
return 0, ErrContentLength
}
if dataB != nil {
return w.w.Write(dataB)
} else {
return w.w.WriteString(dataS)
}
}
func (w *response) finishRequest() {
w.handlerDone.setTrue()
if !w.wroteHeader {
w.WriteHeader(StatusOK)
}
w.w.Flush()
putBufioWriter(w.w)
w.cw.close()
w.conn.bufw.Flush()
w.conn.r.abortPendingRead()
// Close the body (regardless of w.closeAfterReply) so we can
// re-use its bufio.Reader later safely.
w.reqBody.Close()
if w.req.MultipartForm != nil {
w.req.MultipartForm.RemoveAll()
}
}
// shouldReuseConnection reports whether the underlying TCP connection can be reused.
// It must only be called after the handler is done executing.
func (w *response) shouldReuseConnection() bool {
if w.closeAfterReply {
// The request or something set while executing the
// handler indicated we shouldn't reuse this
// connection.
return false
}
if w.req.Method != "HEAD" && w.contentLength != -1 && w.bodyAllowed() && w.contentLength != w.written {
// Did not write enough. Avoid getting out of sync.
return false
}
// There was some error writing to the underlying connection
// during the request, so don't re-use this conn.
if w.conn.werr != nil {
return false
}
if w.closedRequestBodyEarly() {
return false
}
return true
}
func (w *response) closedRequestBodyEarly() bool {
body, ok := w.req.Body.(*body)
return ok && body.didEarlyClose()
}
func (w *response) Flush() {
if !w.wroteHeader {
w.WriteHeader(StatusOK)
}
w.w.Flush()
w.cw.flush()
}
func (c *conn) finalFlush() {
if c.bufr != nil {
// Steal the bufio.Reader (~4KB worth of memory) and its associated
// reader for a future connection.
putBufioReader(c.bufr)
c.bufr = nil
}
if c.bufw != nil {
c.bufw.Flush()
// Steal the bufio.Writer (~4KB worth of memory) and its associated
// writer for a future connection.
putBufioWriter(c.bufw)
c.bufw = nil
}
}
// Close the connection.
func (c *conn) close() {
c.finalFlush()
c.rwc.Close()
}
// rstAvoidanceDelay is the amount of time we sleep after closing the
// write side of a TCP connection before closing the entire socket.
// By sleeping, we increase the chances that the client sees our FIN
// and processes its final data before they process the subsequent RST
// from closing a connection with known unread data.
// This RST seems to occur mostly on BSD systems. (And Windows?)
// This timeout is somewhat arbitrary (~latency around the planet).
const rstAvoidanceDelay = 500 * time.Millisecond
type closeWriter interface {
CloseWrite() error
}
var _ closeWriter = (*net.TCPConn)(nil)
// closeWrite flushes any outstanding data and sends a FIN packet (if
// client is connected via TCP), signalling that we're done. We then
// pause for a bit, hoping the client processes it before any
// subsequent RST.
//
// See https://golang.org/issue/3595
func (c *conn) closeWriteAndWait() {
c.finalFlush()
if tcp, ok := c.rwc.(closeWriter); ok {
tcp.CloseWrite()
}
time.Sleep(rstAvoidanceDelay)
}
// validNextProto reports whether the proto is a valid ALPN protocol name.
// Everything is valid except the empty string and built-in protocol types,
// so that those can't be overridden with alternate implementations.
func validNextProto(proto string) bool {
switch proto {
case "", "http/1.1", "http/1.0":
return false
}
return true
}
const (
runHooks = true
skipHooks = false
)
func (c *conn) setState(nc net.Conn, state ConnState, runHook bool) {
srv := c.server
switch state {
case StateNew:
srv.trackConn(c, true)
case StateHijacked, StateClosed:
srv.trackConn(c, false)
}
if state > 0xff || state < 0 {
panic("internal error")
}
packedState := uint64(time.Now().Unix()<<8) | uint64(state)
atomic.StoreUint64(&c.curState.atomic, packedState)
if !runHook {
return
}
if hook := srv.ConnState; hook != nil {
hook(nc, state)
}
}
func (c *conn) getState() (state ConnState, unixSec int64) {
packedState := atomic.LoadUint64(&c.curState.atomic)
return ConnState(packedState & 0xff), int64(packedState >> 8)
}
// badRequestError is a literal string (used by in the server in HTML,
// unescaped) to tell the user why their request was bad. It should
// be plain text without user info or other embedded errors.
func badRequestError(e string) error { return statusError{StatusBadRequest, e} }
// statusError is an error used to respond to a request with an HTTP status.
// The text should be plain text without user info or other embedded errors.
type statusError struct {
code int
text string
}
func (e statusError) Error() string { return StatusText(e.code) + ": " + e.text }
// ErrAbortHandler is a sentinel panic value to abort a handler.
// While any panic from ServeHTTP aborts the response to the client,
// panicking with ErrAbortHandler also suppresses logging of a stack
// trace to the server's error log.
var ErrAbortHandler = errors.New("net/http: abort Handler")
// isCommonNetReadError reports whether err is a common error
// encountered during reading a request off the network when the
// client has gone away or had its read fail somehow. This is used to
// determine which logs are interesting enough to log about.
func isCommonNetReadError(err error) bool {
if err == io.EOF {
return true
}
if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
return true
}
if oe, ok := err.(*net.OpError); ok && oe.Op == "read" {
return true
}
return false
}
// Serve a new connection.
func (c *conn) serve(ctx context.Context) {
c.remoteAddr = c.rwc.RemoteAddr().String()
ctx = context.WithValue(ctx, LocalAddrContextKey, c.rwc.LocalAddr())
defer func() {
if err := recover(); err != nil && err != ErrAbortHandler {
const size = 64 << 10
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
c.server.logf("http: panic serving %v: %v\n%s", c.remoteAddr, err, buf)
}
if !c.hijacked() {
c.close()
c.setState(c.rwc, StateClosed, runHooks)
}
}()
if tlsConn, ok := c.rwc.(*tls.Conn); ok {
if d := c.server.ReadTimeout; d > 0 {
c.rwc.SetReadDeadline(time.Now().Add(d))
}
if d := c.server.WriteTimeout; d > 0 {
c.rwc.SetWriteDeadline(time.Now().Add(d))
}
if err := tlsConn.HandshakeContext(ctx); err != nil {
// If the handshake failed due to the client not speaking
// TLS, assume they're speaking plaintext HTTP and write a
// 400 response on the TLS conn's underlying net.Conn.
if re, ok := err.(tls.RecordHeaderError); ok && re.Conn != nil && tlsRecordHeaderLooksLikeHTTP(re.RecordHeader) {
io.WriteString(re.Conn, "HTTP/1.0 400 Bad Request\r\n\r\nClient sent an HTTP request to an HTTPS server.\n")
re.Conn.Close()
return
}
c.server.logf("http: TLS handshake error from %s: %v", c.rwc.RemoteAddr(), err)
return
}
c.tlsState = new(tls.ConnectionState)
*c.tlsState = tlsConn.ConnectionState()
if proto := c.tlsState.NegotiatedProtocol; validNextProto(proto) {
if fn := c.server.TLSNextProto[proto]; fn != nil {
h := initALPNRequest{ctx, tlsConn, serverHandler{c.server}}
// Mark freshly created HTTP/2 as active and prevent any server state hooks
// from being run on these connections. This prevents closeIdleConns from
// closing such connections. See issue https://golang.org/issue/39776.
c.setState(c.rwc, StateActive, skipHooks)
fn(c.server, tlsConn, h)
}
return
}
}
// HTTP/1.x from here on.
ctx, cancelCtx := context.WithCancel(ctx)
c.cancelCtx = cancelCtx
defer cancelCtx()
c.r = &connReader{conn: c}
c.bufr = newBufioReader(c.r)
c.bufw = newBufioWriterSize(checkConnErrorWriter{c}, 4<<10)
for {
w, err := c.readRequest(ctx)
if c.r.remain != c.server.initialReadLimitSize() {
// If we read any bytes off the wire, we're active.
c.setState(c.rwc, StateActive, runHooks)
}
if err != nil {
const errorHeaders = "\r\nContent-Type: text/plain; charset=utf-8\r\nConnection: close\r\n\r\n"
switch {
case err == errTooLarge:
// Their HTTP client may or may not be
// able to read this if we're
// responding to them and hanging up
// while they're still writing their
// request. Undefined behavior.
const publicErr = "431 Request Header Fields Too Large"
fmt.Fprintf(c.rwc, "HTTP/1.1 "+publicErr+errorHeaders+publicErr)
c.closeWriteAndWait()
return
case isUnsupportedTEError(err):
// Respond as per RFC 7230 Section 3.3.1 which says,
// A server that receives a request message with a
// transfer coding it does not understand SHOULD
// respond with 501 (Unimplemented).
code := StatusNotImplemented
// We purposefully aren't echoing back the transfer-encoding's value,
// so as to mitigate the risk of cross side scripting by an attacker.
fmt.Fprintf(c.rwc, "HTTP/1.1 %d %s%sUnsupported transfer encoding", code, StatusText(code), errorHeaders)
return
case isCommonNetReadError(err):
return // don't reply
default:
if v, ok := err.(statusError); ok {
fmt.Fprintf(c.rwc, "HTTP/1.1 %d %s: %s%s%d %s: %s", v.code, StatusText(v.code), v.text, errorHeaders, v.code, StatusText(v.code), v.text)
return
}
publicErr := "400 Bad Request"
fmt.Fprintf(c.rwc, "HTTP/1.1 "+publicErr+errorHeaders+publicErr)
return
}
}
// Expect 100 Continue support
req := w.req
if req.expectsContinue() {
if req.ProtoAtLeast(1, 1) && req.ContentLength != 0 {
// Wrap the Body reader with one that replies on the connection
req.Body = &expectContinueReader{readCloser: req.Body, resp: w}
w.canWriteContinue.setTrue()
}
} else if req.Header.get("Expect") != "" {
w.sendExpectationFailed()
return
}
c.curReq.Store(w)
if requestBodyRemains(req.Body) {
registerOnHitEOF(req.Body, w.conn.r.startBackgroundRead)
} else {
w.conn.r.startBackgroundRead()
}
// HTTP cannot have multiple simultaneous active requests.[*]
// Until the server replies to this request, it can't read another,
// so we might as well run the handler in this goroutine.
// [*] Not strictly true: HTTP pipelining. We could let them all process
// in parallel even if their responses need to be serialized.
// But we're not going to implement HTTP pipelining because it
// was never deployed in the wild and the answer is HTTP/2.
serverHandler{c.server}.ServeHTTP(w, w.req)
w.cancelCtx()
if c.hijacked() {
return
}
w.finishRequest()
if !w.shouldReuseConnection() {
if w.requestBodyLimitHit || w.closedRequestBodyEarly() {
c.closeWriteAndWait()
}
return
}
c.setState(c.rwc, StateIdle, runHooks)
c.curReq.Store((*response)(nil))
if !w.conn.server.doKeepAlives() {
// We're in shutdown mode. We might've replied
// to the user without "Connection: close" and
// they might think they can send another
// request, but such is life with HTTP/1.1.
return
}
if d := c.server.idleTimeout(); d != 0 {
c.rwc.SetReadDeadline(time.Now().Add(d))
if _, err := c.bufr.Peek(4); err != nil {
return
}
}
c.rwc.SetReadDeadline(time.Time{})
}
}
func (w *response) sendExpectationFailed() {
// TODO(bradfitz): let ServeHTTP handlers handle
// requests with non-standard expectation[s]? Seems
// theoretical at best, and doesn't fit into the
// current ServeHTTP model anyway. We'd need to
// make the ResponseWriter an optional
// "ExpectReplier" interface or something.
//
// For now we'll just obey RFC 7231 5.1.1 which says
// "A server that receives an Expect field-value other
// than 100-continue MAY respond with a 417 (Expectation
// Failed) status code to indicate that the unexpected
// expectation cannot be met."
w.Header().Set("Connection", "close")
w.WriteHeader(StatusExpectationFailed)
w.finishRequest()
}
// Hijack implements the Hijacker.Hijack method. Our response is both a ResponseWriter
// and a Hijacker.
func (w *response) Hijack() (rwc net.Conn, buf *bufio.ReadWriter, err error) {
if w.handlerDone.isSet() {
panic("net/http: Hijack called after ServeHTTP finished")
}
if w.wroteHeader {
w.cw.flush()
}
c := w.conn
c.mu.Lock()
defer c.mu.Unlock()
// Release the bufioWriter that writes to the chunk writer, it is not
// used after a connection has been hijacked.
rwc, buf, err = c.hijackLocked()
if err == nil {
putBufioWriter(w.w)
w.w = nil
}
return rwc, buf, err
}
func (w *response) CloseNotify() <-chan bool {
if w.handlerDone.isSet() {
panic("net/http: CloseNotify called after ServeHTTP finished")
}
return w.closeNotifyCh
}
func registerOnHitEOF(rc io.ReadCloser, fn func()) {
switch v := rc.(type) {
case *expectContinueReader:
registerOnHitEOF(v.readCloser, fn)
case *body:
v.registerOnHitEOF(fn)
default:
panic("unexpected type " + fmt.Sprintf("%T", rc))
}
}
// requestBodyRemains reports whether future calls to Read
// on rc might yield more data.
func requestBodyRemains(rc io.ReadCloser) bool {
if rc == NoBody {
return false
}
switch v := rc.(type) {
case *expectContinueReader:
return requestBodyRemains(v.readCloser)
case *body:
return v.bodyRemains()
default:
panic("unexpected type " + fmt.Sprintf("%T", rc))
}
}
// The HandlerFunc type is an adapter to allow the use of
// ordinary functions as HTTP handlers. If f is a function
// with the appropriate signature, HandlerFunc(f) is a
// Handler that calls f.
type HandlerFunc func(ResponseWriter, *Request)
// ServeHTTP calls f(w, r).
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
f(w, r)
}
// Helper handlers
// Error replies to the request with the specified error message and HTTP code.
// It does not otherwise end the request; the caller should ensure no further
// writes are done to w.
// The error message should be plain text.
func Error(w ResponseWriter, error string, code int) {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.Header().Set("X-Content-Type-Options", "nosniff")
w.WriteHeader(code)
fmt.Fprintln(w, error)
}
// NotFound replies to the request with an HTTP 404 not found error.
func NotFound(w ResponseWriter, r *Request) { Error(w, "404 page not found", StatusNotFound) }
// NotFoundHandler returns a simple request handler
// that replies to each request with a ``404 page not found'' reply.
func NotFoundHandler() Handler { return HandlerFunc(NotFound) }
// StripPrefix returns a handler that serves HTTP requests by removing the
// given prefix from the request URL's Path (and RawPath if set) and invoking
// the handler h. StripPrefix handles a request for a path that doesn't begin
// with prefix by replying with an HTTP 404 not found error. The prefix must
// match exactly: if the prefix in the request contains escaped characters
// the reply is also an HTTP 404 not found error.
func StripPrefix(prefix string, h Handler) Handler {
if prefix == "" {
return h
}
return HandlerFunc(func(w ResponseWriter, r *Request) {
p := strings.TrimPrefix(r.URL.Path, prefix)
rp := strings.TrimPrefix(r.URL.RawPath, prefix)
if len(p) < len(r.URL.Path) && (r.URL.RawPath == "" || len(rp) < len(r.URL.RawPath)) {
r2 := new(Request)
*r2 = *r
r2.URL = new(url.URL)
*r2.URL = *r.URL
r2.URL.Path = p
r2.URL.RawPath = rp
h.ServeHTTP(w, r2)
} else {
NotFound(w, r)
}
})
}
// Redirect replies to the request with a redirect to url,
// which may be a path relative to the request path.
//
// The provided code should be in the 3xx range and is usually
// StatusMovedPermanently, StatusFound or StatusSeeOther.
//
// If the Content-Type header has not been set, Redirect sets it
// to "text/html; charset=utf-8" and writes a small HTML body.
// Setting the Content-Type header to any value, including nil,
// disables that behavior.
func Redirect(w ResponseWriter, r *Request, url string, code int) {
if u, err := urlpkg.Parse(url); err == nil {
// If url was relative, make its path absolute by
// combining with request path.
// The client would probably do this for us,
// but doing it ourselves is more reliable.
// See RFC 7231, section 7.1.2
if u.Scheme == "" && u.Host == "" {
oldpath := r.URL.Path
if oldpath == "" { // should not happen, but avoid a crash if it does
oldpath = "/"
}
// no leading http://server
if url == "" || url[0] != '/' {
// make relative path absolute
olddir, _ := path.Split(oldpath)
url = olddir + url
}
var query string
if i := strings.Index(url, "?"); i != -1 {
url, query = url[:i], url[i:]
}
// clean up but preserve trailing slash
trailing := strings.HasSuffix(url, "/")
url = path.Clean(url)
if trailing && !strings.HasSuffix(url, "/") {
url += "/"
}
url += query
}
}
h := w.Header()
// RFC 7231 notes that a short HTML body is usually included in
// the response because older user agents may not understand 301/307.
// Do it only if the request didn't already have a Content-Type header.
_, hadCT := h["Content-Type"]
h.Set("Location", hexEscapeNonASCII(url))
if !hadCT && (r.Method == "GET" || r.Method == "HEAD") {
h.Set("Content-Type", "text/html; charset=utf-8")
}
w.WriteHeader(code)
// Shouldn't send the body for POST or HEAD; that leaves GET.
if !hadCT && r.Method == "GET" {
body := "<a href=\"" + htmlEscape(url) + "\">" + statusText[code] + "</a>.\n"
fmt.Fprintln(w, body)
}
}
var htmlReplacer = strings.NewReplacer(
"&", "&",
"<", "<",
">", ">",
// """ is shorter than """.
`"`, """,
// "'" is shorter than "'" and apos was not in HTML until HTML5.
"'", "'",
)
func htmlEscape(s string) string {
return htmlReplacer.Replace(s)
}
// Redirect to a fixed URL
type redirectHandler struct {
url string
code int
}
func (rh *redirectHandler) ServeHTTP(w ResponseWriter, r *Request) {
Redirect(w, r, rh.url, rh.code)
}
// RedirectHandler returns a request handler that redirects
// each request it receives to the given url using the given
// status code.
//
// The provided code should be in the 3xx range and is usually
// StatusMovedPermanently, StatusFound or StatusSeeOther.
func RedirectHandler(url string, code int) Handler {
return &redirectHandler{url, code}
}
// ServeMux is an HTTP request multiplexer.
// It matches the URL of each incoming request against a list of registered
// patterns and calls the handler for the pattern that
// most closely matches the URL.
//
// Patterns name fixed, rooted paths, like "/favicon.ico",
// or rooted subtrees, like "/images/" (note the trailing slash).
// Longer patterns take precedence over shorter ones, so that
// if there are handlers registered for both "/images/"
// and "/images/thumbnails/", the latter handler will be
// called for paths beginning "/images/thumbnails/" and the
// former will receive requests for any other paths in the
// "/images/" subtree.
//
// Note that since a pattern ending in a slash names a rooted subtree,
// the pattern "/" matches all paths not matched by other registered
// patterns, not just the URL with Path == "/".
//
// If a subtree has been registered and a request is received naming the
// subtree root without its trailing slash, ServeMux redirects that
// request to the subtree root (adding the trailing slash). This behavior can
// be overridden with a separate registration for the path without
// the trailing slash. For example, registering "/images/" causes ServeMux
// to redirect a request for "/images" to "/images/", unless "/images" has
// been registered separately.
//
// Patterns may optionally begin with a host name, restricting matches to
// URLs on that host only. Host-specific patterns take precedence over
// general patterns, so that a handler might register for the two patterns
// "/codesearch" and "codesearch.google.com/" without also taking over
// requests for "http://www.google.com/".
//
// ServeMux also takes care of sanitizing the URL request path and the Host
// header, stripping the port number and redirecting any request containing . or
// .. elements or repeated slashes to an equivalent, cleaner URL.
type ServeMux struct {
mu sync.RWMutex
m map[string]muxEntry
es []muxEntry // slice of entries sorted from longest to shortest.
hosts bool // whether any patterns contain hostnames
}
type muxEntry struct {
h Handler
pattern string
}
// NewServeMux allocates and returns a new ServeMux.
func NewServeMux() *ServeMux { return new(ServeMux) }
// DefaultServeMux is the default ServeMux used by Serve.
var DefaultServeMux = &defaultServeMux
var defaultServeMux ServeMux
// cleanPath returns the canonical path for p, eliminating . and .. elements.
func cleanPath(p string) string {
if p == "" {
return "/"
}
if p[0] != '/' {
p = "/" + p
}
np := path.Clean(p)
// path.Clean removes trailing slash except for root;
// put the trailing slash back if necessary.
if p[len(p)-1] == '/' && np != "/" {
// Fast path for common case of p being the string we want:
if len(p) == len(np)+1 && strings.HasPrefix(p, np) {
np = p
} else {
np += "/"
}
}
return np
}
// stripHostPort returns h without any trailing ":<port>".
func stripHostPort(h string) string {
// If no port on host, return unchanged
if strings.IndexByte(h, ':') == -1 {
return h
}
host, _, err := net.SplitHostPort(h)
if err != nil {
return h // on error, return unchanged
}
return host
}
// Find a handler on a handler map given a path string.
// Most-specific (longest) pattern wins.
func (mux *ServeMux) match(path string) (h Handler, pattern string) {
// Check for exact match first.
v, ok := mux.m[path]
if ok {
return v.h, v.pattern
}
// Check for longest valid match. mux.es contains all patterns
// that end in / sorted from longest to shortest.
for _, e := range mux.es {
if strings.HasPrefix(path, e.pattern) {
return e.h, e.pattern
}
}
return nil, ""
}
// redirectToPathSlash determines if the given path needs appending "/" to it.
// This occurs when a handler for path + "/" was already registered, but
// not for path itself. If the path needs appending to, it creates a new
// URL, setting the path to u.Path + "/" and returning true to indicate so.
func (mux *ServeMux) redirectToPathSlash(host, path string, u *url.URL) (*url.URL, bool) {
mux.mu.RLock()
shouldRedirect := mux.shouldRedirectRLocked(host, path)
mux.mu.RUnlock()
if !shouldRedirect {
return u, false
}
path = path + "/"
u = &url.URL{Path: path, RawQuery: u.RawQuery}
return u, true
}
// shouldRedirectRLocked reports whether the given path and host should be redirected to
// path+"/". This should happen if a handler is registered for path+"/" but
// not path -- see comments at ServeMux.
func (mux *ServeMux) shouldRedirectRLocked(host, path string) bool {
p := []string{path, host + path}
for _, c := range p {
if _, exist := mux.m[c]; exist {
return false
}
}
n := len(path)
if n == 0 {
return false
}
for _, c := range p {
if _, exist := mux.m[c+"/"]; exist {
return path[n-1] != '/'
}
}
return false
}
// Handler returns the handler to use for the given request,
// consulting r.Method, r.Host, and r.URL.Path. It always returns
// a non-nil handler. If the path is not in its canonical form, the
// handler will be an internally-generated handler that redirects
// to the canonical path. If the host contains a port, it is ignored
// when matching handlers.
//
// The path and host are used unchanged for CONNECT requests.
//
// Handler also returns the registered pattern that matches the
// request or, in the case of internally-generated redirects,
// the pattern that will match after following the redirect.
//
// If there is no registered handler that applies to the request,
// Handler returns a ``page not found'' handler and an empty pattern.
func (mux *ServeMux) Handler(r *Request) (h Handler, pattern string) {
// CONNECT requests are not canonicalized.
if r.Method == "CONNECT" {
// If r.URL.Path is /tree and its handler is not registered,
// the /tree -> /tree/ redirect applies to CONNECT requests
// but the path canonicalization does not.
if u, ok := mux.redirectToPathSlash(r.URL.Host, r.URL.Path, r.URL); ok {
return RedirectHandler(u.String(), StatusMovedPermanently), u.Path
}
return mux.handler(r.Host, r.URL.Path)
}
// All other requests have any port stripped and path cleaned
// before passing to mux.handler.
host := stripHostPort(r.Host)
path := cleanPath(r.URL.Path)
// If the given path is /tree and its handler is not registered,
// redirect for /tree/.
if u, ok := mux.redirectToPathSlash(host, path, r.URL); ok {
return RedirectHandler(u.String(), StatusMovedPermanently), u.Path
}
if path != r.URL.Path {
_, pattern = mux.handler(host, path)
u := &url.URL{Path: path, RawQuery: r.URL.RawQuery}
return RedirectHandler(u.String(), StatusMovedPermanently), pattern
}
return mux.handler(host, r.URL.Path)
}
// handler is the main implementation of Handler.
// The path is known to be in canonical form, except for CONNECT methods.
func (mux *ServeMux) handler(host, path string) (h Handler, pattern string) {
mux.mu.RLock()
defer mux.mu.RUnlock()
// Host-specific pattern takes precedence over generic ones
if mux.hosts {
h, pattern = mux.match(host + path)
}
if h == nil {
h, pattern = mux.match(path)
}
if h == nil {
h, pattern = NotFoundHandler(), ""
}
return
}
// ServeHTTP dispatches the request to the handler whose
// pattern most closely matches the request URL.
func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
if r.RequestURI == "*" {
if r.ProtoAtLeast(1, 1) {
w.Header().Set("Connection", "close")
}
w.WriteHeader(StatusBadRequest)
return
}
h, _ := mux.Handler(r)
h.ServeHTTP(w, r)
}
// Handle registers the handler for the given pattern.
// If a handler already exists for pattern, Handle panics.
func (mux *ServeMux) Handle(pattern string, handler Handler) {
mux.mu.Lock()
defer mux.mu.Unlock()
if pattern == "" {
panic("http: invalid pattern")
}
if handler == nil {
panic("http: nil handler")
}
if _, exist := mux.m[pattern]; exist {
panic("http: multiple registrations for " + pattern)
}
if mux.m == nil {
mux.m = make(map[string]muxEntry)
}
e := muxEntry{h: handler, pattern: pattern}
mux.m[pattern] = e
if pattern[len(pattern)-1] == '/' {
mux.es = appendSorted(mux.es, e)
}
if pattern[0] != '/' {
mux.hosts = true
}
}
func appendSorted(es []muxEntry, e muxEntry) []muxEntry {
n := len(es)
i := sort.Search(n, func(i int) bool {
return len(es[i].pattern) < len(e.pattern)
})
if i == n {
return append(es, e)
}
// we now know that i points at where we want to insert
es = append(es, muxEntry{}) // try to grow the slice in place, any entry works.
copy(es[i+1:], es[i:]) // Move shorter entries down
es[i] = e
return es
}
// HandleFunc registers the handler function for the given pattern.
func (mux *ServeMux) HandleFunc(pattern string, handler func(ResponseWriter, *Request)) {
if handler == nil {
panic("http: nil handler")
}
mux.Handle(pattern, HandlerFunc(handler))
}
// Handle registers the handler for the given pattern
// in the DefaultServeMux.
// The documentation for ServeMux explains how patterns are matched.
func Handle(pattern string, handler Handler) { DefaultServeMux.Handle(pattern, handler) }
// HandleFunc registers the handler function for the given pattern
// in the DefaultServeMux.
// The documentation for ServeMux explains how patterns are matched.
func HandleFunc(pattern string, handler func(ResponseWriter, *Request)) {
DefaultServeMux.HandleFunc(pattern, handler)
}
// Serve accepts incoming HTTP connections on the listener l,
// creating a new service goroutine for each. The service goroutines
// read requests and then call handler to reply to them.
//
// The handler is typically nil, in which case the DefaultServeMux is used.
//
// HTTP/2 support is only enabled if the Listener returns *tls.Conn
// connections and they were configured with "h2" in the TLS
// Config.NextProtos.
//
// Serve always returns a non-nil error.
func Serve(l net.Listener, handler Handler) error {
srv := &Server{Handler: handler}
return srv.Serve(l)
}
// ServeTLS accepts incoming HTTPS connections on the listener l,
// creating a new service goroutine for each. The service goroutines
// read requests and then call handler to reply to them.
//
// The handler is typically nil, in which case the DefaultServeMux is used.
//
// Additionally, files containing a certificate and matching private key
// for the server must be provided. If the certificate is signed by a
// certificate authority, the certFile should be the concatenation
// of the server's certificate, any intermediates, and the CA's certificate.
//
// ServeTLS always returns a non-nil error.
func ServeTLS(l net.Listener, handler Handler, certFile, keyFile string) error {
srv := &Server{Handler: handler}
return srv.ServeTLS(l, certFile, keyFile)
}
// A Server defines parameters for running an HTTP server.
// The zero value for Server is a valid configuration.
type Server struct {
// Addr optionally specifies the TCP address for the server to listen on,
// in the form "host:port". If empty, ":http" (port 80) is used.
// The service names are defined in RFC 6335 and assigned by IANA.
// See net.Dial for details of the address format.
Addr string
Handler Handler // handler to invoke, http.DefaultServeMux if nil
// TLSConfig optionally provides a TLS configuration for use
// by ServeTLS and ListenAndServeTLS. Note that this value is
// cloned by ServeTLS and ListenAndServeTLS, so it's not
// possible to modify the configuration with methods like
// tls.Config.SetSessionTicketKeys. To use
// SetSessionTicketKeys, use Server.Serve with a TLS Listener
// instead.
TLSConfig *tls.Config
// ReadTimeout is the maximum duration for reading the entire
// request, including the body. A zero or negative value means
// there will be no timeout.
//
// Because ReadTimeout does not let Handlers make per-request
// decisions on each request body's acceptable deadline or
// upload rate, most users will prefer to use
// ReadHeaderTimeout. It is valid to use them both.
ReadTimeout time.Duration
// ReadHeaderTimeout is the amount of time allowed to read
// request headers. The connection's read deadline is reset
// after reading the headers and the Handler can decide what
// is considered too slow for the body. If ReadHeaderTimeout
// is zero, the value of ReadTimeout is used. If both are
// zero, there is no timeout.
ReadHeaderTimeout time.Duration
// WriteTimeout is the maximum duration before timing out
// writes of the response. It is reset whenever a new
// request's header is read. Like ReadTimeout, it does not
// let Handlers make decisions on a per-request basis.
// A zero or negative value means there will be no timeout.
WriteTimeout time.Duration
// IdleTimeout is the maximum amount of time to wait for the
// next request when keep-alives are enabled. If IdleTimeout
// is zero, the value of ReadTimeout is used. If both are
// zero, there is no timeout.
IdleTimeout time.Duration
// MaxHeaderBytes controls the maximum number of bytes the
// server will read parsing the request header's keys and
// values, including the request line. It does not limit the
// size of the request body.
// If zero, DefaultMaxHeaderBytes is used.
MaxHeaderBytes int
// TLSNextProto optionally specifies a function to take over
// ownership of the provided TLS connection when an ALPN
// protocol upgrade has occurred. The map key is the protocol
// name negotiated. The Handler argument should be used to
// handle HTTP requests and will initialize the Request's TLS
// and RemoteAddr if not already set. The connection is
// automatically closed when the function returns.
// If TLSNextProto is not nil, HTTP/2 support is not enabled
// automatically.
TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
// ConnState specifies an optional callback function that is
// called when a client connection changes state. See the
// ConnState type and associated constants for details.
ConnState func(net.Conn, ConnState)
// ErrorLog specifies an optional logger for errors accepting
// connections, unexpected behavior from handlers, and
// underlying FileSystem errors.
// If nil, logging is done via the log package's standard logger.
ErrorLog *log.Logger
// BaseContext optionally specifies a function that returns
// the base context for incoming requests on this server.
// The provided Listener is the specific Listener that's
// about to start accepting requests.
// If BaseContext is nil, the default is context.Background().
// If non-nil, it must return a non-nil context.
BaseContext func(net.Listener) context.Context
// ConnContext optionally specifies a function that modifies
// the context used for a new connection c. The provided ctx
// is derived from the base context and has a ServerContextKey
// value.
ConnContext func(ctx context.Context, c net.Conn) context.Context
inShutdown atomicBool // true when server is in shutdown
disableKeepAlives int32 // accessed atomically.
nextProtoOnce sync.Once // guards setupHTTP2_* init
nextProtoErr error // result of http2.ConfigureServer if used
mu sync.Mutex
listeners map[*net.Listener]struct{}
activeConn map[*conn]struct{}
doneChan chan struct{}
onShutdown []func()
}
func (s *Server) getDoneChan() <-chan struct{} {
s.mu.Lock()
defer s.mu.Unlock()
return s.getDoneChanLocked()
}
func (s *Server) getDoneChanLocked() chan struct{} {
if s.doneChan == nil {
s.doneChan = make(chan struct{})
}
return s.doneChan
}
func (s *Server) closeDoneChanLocked() {
ch := s.getDoneChanLocked()
select {
case <-ch:
// Already closed. Don't close again.
default:
// Safe to close here. We're the only closer, guarded
// by s.mu.
close(ch)
}
}
// Close immediately closes all active net.Listeners and any
// connections in state StateNew, StateActive, or StateIdle. For a
// graceful shutdown, use Shutdown.
//
// Close does not attempt to close (and does not even know about)
// any hijacked connections, such as WebSockets.
//
// Close returns any error returned from closing the Server's
// underlying Listener(s).
func (srv *Server) Close() error {
srv.inShutdown.setTrue()
srv.mu.Lock()
defer srv.mu.Unlock()
srv.closeDoneChanLocked()
err := srv.closeListenersLocked()
for c := range srv.activeConn {
c.rwc.Close()
delete(srv.activeConn, c)
}
return err
}
// shutdownPollIntervalMax is the max polling interval when checking
// quiescence during Server.Shutdown. Polling starts with a small
// interval and backs off to the max.
// Ideally we could find a solution that doesn't involve polling,
// but which also doesn't have a high runtime cost (and doesn't
// involve any contentious mutexes), but that is left as an
// exercise for the reader.
const shutdownPollIntervalMax = 500 * time.Millisecond
// Shutdown gracefully shuts down the server without interrupting any
// active connections. Shutdown works by first closing all open
// listeners, then closing all idle connections, and then waiting
// indefinitely for connections to return to idle and then shut down.
// If the provided context expires before the shutdown is complete,
// Shutdown returns the context's error, otherwise it returns any
// error returned from closing the Server's underlying Listener(s).
//
// When Shutdown is called, Serve, ListenAndServe, and
// ListenAndServeTLS immediately return ErrServerClosed. Make sure the
// program doesn't exit and waits instead for Shutdown to return.
//
// Shutdown does not attempt to close nor wait for hijacked
// connections such as WebSockets. The caller of Shutdown should
// separately notify such long-lived connections of shutdown and wait
// for them to close, if desired. See RegisterOnShutdown for a way to
// register shutdown notification functions.
//
// Once Shutdown has been called on a server, it may not be reused;
// future calls to methods such as Serve will return ErrServerClosed.
func (srv *Server) Shutdown(ctx context.Context) error {
srv.inShutdown.setTrue()
srv.mu.Lock()
lnerr := srv.closeListenersLocked()
srv.closeDoneChanLocked()
for _, f := range srv.onShutdown {
go f()
}
srv.mu.Unlock()
pollIntervalBase := time.Millisecond
nextPollInterval := func() time.Duration {
// Add 10% jitter.
interval := pollIntervalBase + time.Duration(rand.Intn(int(pollIntervalBase/10)))
// Double and clamp for next time.
pollIntervalBase *= 2
if pollIntervalBase > shutdownPollIntervalMax {
pollIntervalBase = shutdownPollIntervalMax
}
return interval
}
timer := time.NewTimer(nextPollInterval())
defer timer.Stop()
for {
if srv.closeIdleConns() && srv.numListeners() == 0 {
return lnerr
}
select {
case <-ctx.Done():
return ctx.Err()
case <-timer.C:
timer.Reset(nextPollInterval())
}
}
}
// RegisterOnShutdown registers a function to call on Shutdown.
// This can be used to gracefully shutdown connections that have
// undergone ALPN protocol upgrade or that have been hijacked.
// This function should start protocol-specific graceful shutdown,
// but should not wait for shutdown to complete.
func (srv *Server) RegisterOnShutdown(f func()) {
srv.mu.Lock()
srv.onShutdown = append(srv.onShutdown, f)
srv.mu.Unlock()
}
func (s *Server) numListeners() int {
s.mu.Lock()
defer s.mu.Unlock()
return len(s.listeners)
}
// closeIdleConns closes all idle connections and reports whether the
// server is quiescent.
func (s *Server) closeIdleConns() bool {
s.mu.Lock()
defer s.mu.Unlock()
quiescent := true
for c := range s.activeConn {
st, unixSec := c.getState()
// Issue 22682: treat StateNew connections as if
// they're idle if we haven't read the first request's
// header in over 5 seconds.
if st == StateNew && unixSec < time.Now().Unix()-5 {
st = StateIdle
}
if st != StateIdle || unixSec == 0 {
// Assume unixSec == 0 means it's a very new
// connection, without state set yet.
quiescent = false
continue
}
c.rwc.Close()
delete(s.activeConn, c)
}
return quiescent
}
func (s *Server) closeListenersLocked() error {
var err error
for ln := range s.listeners {
if cerr := (*ln).Close(); cerr != nil && err == nil {
err = cerr
}
}
return err
}
// A ConnState represents the state of a client connection to a server.
// It's used by the optional Server.ConnState hook.
type ConnState int
const (
// StateNew represents a new connection that is expected to
// send a request immediately. Connections begin at this
// state and then transition to either StateActive or
// StateClosed.
StateNew ConnState = iota
// StateActive represents a connection that has read 1 or more
// bytes of a request. The Server.ConnState hook for
// StateActive fires before the request has entered a handler
// and doesn't fire again until the request has been
// handled. After the request is handled, the state
// transitions to StateClosed, StateHijacked, or StateIdle.
// For HTTP/2, StateActive fires on the transition from zero
// to one active request, and only transitions away once all
// active requests are complete. That means that ConnState
// cannot be used to do per-request work; ConnState only notes
// the overall state of the connection.
StateActive
// StateIdle represents a connection that has finished
// handling a request and is in the keep-alive state, waiting
// for a new request. Connections transition from StateIdle
// to either StateActive or StateClosed.
StateIdle
// StateHijacked represents a hijacked connection.
// This is a terminal state. It does not transition to StateClosed.
StateHijacked
// StateClosed represents a closed connection.
// This is a terminal state. Hijacked connections do not
// transition to StateClosed.
StateClosed
)
var stateName = map[ConnState]string{
StateNew: "new",
StateActive: "active",
StateIdle: "idle",
StateHijacked: "hijacked",
StateClosed: "closed",
}
func (c ConnState) String() string {
return stateName[c]
}
// serverHandler delegates to either the server's Handler or
// DefaultServeMux and also handles "OPTIONS *" requests.
type serverHandler struct {
srv *Server
}
func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
handler := sh.srv.Handler
if handler == nil {
handler = DefaultServeMux
}
if req.RequestURI == "*" && req.Method == "OPTIONS" {
handler = globalOptionsHandler{}
}
if req.URL != nil && strings.Contains(req.URL.RawQuery, ";") {
var allowQuerySemicolonsInUse int32
req = req.WithContext(context.WithValue(req.Context(), silenceSemWarnContextKey, func() {
atomic.StoreInt32(&allowQuerySemicolonsInUse, 1)
}))
defer func() {
if atomic.LoadInt32(&allowQuerySemicolonsInUse) == 0 {
sh.srv.logf("http: URL query contains semicolon, which is no longer a supported separator; parts of the query may be stripped when parsed; see golang.org/issue/25192")
}
}()
}
handler.ServeHTTP(rw, req)
}
var silenceSemWarnContextKey = &contextKey{"silence-semicolons"}
// AllowQuerySemicolons returns a handler that serves requests by converting any
// unescaped semicolons in the URL query to ampersands, and invoking the handler h.
//
// This restores the pre-Go 1.17 behavior of splitting query parameters on both
// semicolons and ampersands. (See golang.org/issue/25192). Note that this
// behavior doesn't match that of many proxies, and the mismatch can lead to
// security issues.
//
// AllowQuerySemicolons should be invoked before Request.ParseForm is called.
func AllowQuerySemicolons(h Handler) Handler {
return HandlerFunc(func(w ResponseWriter, r *Request) {
if silenceSemicolonsWarning, ok := r.Context().Value(silenceSemWarnContextKey).(func()); ok {
silenceSemicolonsWarning()
}
if strings.Contains(r.URL.RawQuery, ";") {
r2 := new(Request)
*r2 = *r
r2.URL = new(url.URL)
*r2.URL = *r.URL
r2.URL.RawQuery = strings.ReplaceAll(r.URL.RawQuery, ";", "&")
h.ServeHTTP(w, r2)
} else {
h.ServeHTTP(w, r)
}
})
}
// ListenAndServe listens on the TCP network address srv.Addr and then
// calls Serve to handle requests on incoming connections.
// Accepted connections are configured to enable TCP keep-alives.
//
// If srv.Addr is blank, ":http" is used.
//
// ListenAndServe always returns a non-nil error. After Shutdown or Close,
// the returned error is ErrServerClosed.
func (srv *Server) ListenAndServe() error {
if srv.shuttingDown() {
return ErrServerClosed
}
addr := srv.Addr
if addr == "" {
addr = ":http"
}
ln, err := net.Listen("tcp", addr)
if err != nil {
return err
}
return srv.Serve(ln)
}
var testHookServerServe func(*Server, net.Listener) // used if non-nil
// shouldDoServeHTTP2 reports whether Server.Serve should configure
// automatic HTTP/2. (which sets up the srv.TLSNextProto map)
func (srv *Server) shouldConfigureHTTP2ForServe() bool {
if srv.TLSConfig == nil {
// Compatibility with Go 1.6:
// If there's no TLSConfig, it's possible that the user just
// didn't set it on the http.Server, but did pass it to
// tls.NewListener and passed that listener to Serve.
// So we should configure HTTP/2 (to set up srv.TLSNextProto)
// in case the listener returns an "h2" *tls.Conn.
return true
}
// The user specified a TLSConfig on their http.Server.
// In this, case, only configure HTTP/2 if their tls.Config
// explicitly mentions "h2". Otherwise http2.ConfigureServer
// would modify the tls.Config to add it, but they probably already
// passed this tls.Config to tls.NewListener. And if they did,
// it's too late anyway to fix it. It would only be potentially racy.
// See Issue 15908.
return strSliceContains(srv.TLSConfig.NextProtos, http2NextProtoTLS)
}
// ErrServerClosed is returned by the Server's Serve, ServeTLS, ListenAndServe,
// and ListenAndServeTLS methods after a call to Shutdown or Close.
var ErrServerClosed = errors.New("http: Server closed")
// Serve accepts incoming connections on the Listener l, creating a
// new service goroutine for each. The service goroutines read requests and
// then call srv.Handler to reply to them.
//
// HTTP/2 support is only enabled if the Listener returns *tls.Conn
// connections and they were configured with "h2" in the TLS
// Config.NextProtos.
//
// Serve always returns a non-nil error and closes l.
// After Shutdown or Close, the returned error is ErrServerClosed.
func (srv *Server) Serve(l net.Listener) error {
if fn := testHookServerServe; fn != nil {
fn(srv, l) // call hook with unwrapped listener
}
origListener := l
l = &onceCloseListener{Listener: l}
defer l.Close()
if err := srv.setupHTTP2_Serve(); err != nil {
return err
}
if !srv.trackListener(&l, true) {
return ErrServerClosed
}
defer srv.trackListener(&l, false)
baseCtx := context.Background()
if srv.BaseContext != nil {
baseCtx = srv.BaseContext(origListener)
if baseCtx == nil {
panic("BaseContext returned a nil context")
}
}
var tempDelay time.Duration // how long to sleep on accept failure
ctx := context.WithValue(baseCtx, ServerContextKey, srv)
for {
rw, err := l.Accept()
if err != nil {
select {
case <-srv.getDoneChan():
return ErrServerClosed
default:
}
if ne, ok := err.(net.Error); ok && ne.Temporary() {
if tempDelay == 0 {
tempDelay = 5 * time.Millisecond
} else {
tempDelay *= 2
}
if max := 1 * time.Second; tempDelay > max {
tempDelay = max
}
srv.logf("http: Accept error: %v; retrying in %v", err, tempDelay)
time.Sleep(tempDelay)
continue
}
return err
}
connCtx := ctx
if cc := srv.ConnContext; cc != nil {
connCtx = cc(connCtx, rw)
if connCtx == nil {
panic("ConnContext returned nil")
}
}
tempDelay = 0
c := srv.newConn(rw)
c.setState(c.rwc, StateNew, runHooks) // before Serve can return
go c.serve(connCtx)
}
}
// ServeTLS accepts incoming connections on the Listener l, creating a
// new service goroutine for each. The service goroutines perform TLS
// setup and then read requests, calling srv.Handler to reply to them.
//
// Files containing a certificate and matching private key for the
// server must be provided if neither the Server's
// TLSConfig.Certificates nor TLSConfig.GetCertificate are populated.
// If the certificate is signed by a certificate authority, the
// certFile should be the concatenation of the server's certificate,
// any intermediates, and the CA's certificate.
//
// ServeTLS always returns a non-nil error. After Shutdown or Close, the
// returned error is ErrServerClosed.
func (srv *Server) ServeTLS(l net.Listener, certFile, keyFile string) error {
// Setup HTTP/2 before srv.Serve, to initialize srv.TLSConfig
// before we clone it and create the TLS Listener.
if err := srv.setupHTTP2_ServeTLS(); err != nil {
return err
}
config := cloneTLSConfig(srv.TLSConfig)
if !strSliceContains(config.NextProtos, "http/1.1") {
config.NextProtos = append(config.NextProtos, "http/1.1")
}
configHasCert := len(config.Certificates) > 0 || config.GetCertificate != nil
if !configHasCert || certFile != "" || keyFile != "" {
var err error
config.Certificates = make([]tls.Certificate, 1)
config.Certificates[0], err = tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
return err
}
}
tlsListener := tls.NewListener(l, config)
return srv.Serve(tlsListener)
}
// trackListener adds or removes a net.Listener to the set of tracked
// listeners.
//
// We store a pointer to interface in the map set, in case the
// net.Listener is not comparable. This is safe because we only call
// trackListener via Serve and can track+defer untrack the same
// pointer to local variable there. We never need to compare a
// Listener from another caller.
//
// It reports whether the server is still up (not Shutdown or Closed).
func (s *Server) trackListener(ln *net.Listener, add bool) bool {
s.mu.Lock()
defer s.mu.Unlock()
if s.listeners == nil {
s.listeners = make(map[*net.Listener]struct{})
}
if add {
if s.shuttingDown() {
return false
}
s.listeners[ln] = struct{}{}
} else {
delete(s.listeners, ln)
}
return true
}
func (s *Server) trackConn(c *conn, add bool) {
s.mu.Lock()
defer s.mu.Unlock()
if s.activeConn == nil {
s.activeConn = make(map[*conn]struct{})
}
if add {
s.activeConn[c] = struct{}{}
} else {
delete(s.activeConn, c)
}
}
func (s *Server) idleTimeout() time.Duration {
if s.IdleTimeout != 0 {
return s.IdleTimeout
}
return s.ReadTimeout
}
func (s *Server) readHeaderTimeout() time.Duration {
if s.ReadHeaderTimeout != 0 {
return s.ReadHeaderTimeout
}
return s.ReadTimeout
}
func (s *Server) doKeepAlives() bool {
return atomic.LoadInt32(&s.disableKeepAlives) == 0 && !s.shuttingDown()
}
func (s *Server) shuttingDown() bool {
return s.inShutdown.isSet()
}
// SetKeepAlivesEnabled controls whether HTTP keep-alives are enabled.
// By default, keep-alives are always enabled. Only very
// resource-constrained environments or servers in the process of
// shutting down should disable them.
func (srv *Server) SetKeepAlivesEnabled(v bool) {
if v {
atomic.StoreInt32(&srv.disableKeepAlives, 0)
return
}
atomic.StoreInt32(&srv.disableKeepAlives, 1)
// Close idle HTTP/1 conns:
srv.closeIdleConns()
// TODO: Issue 26303: close HTTP/2 conns as soon as they become idle.
}
func (s *Server) logf(format string, args ...interface{}) {
if s.ErrorLog != nil {
s.ErrorLog.Printf(format, args...)
} else {
log.Printf(format, args...)
}
}
// logf prints to the ErrorLog of the *Server associated with request r
// via ServerContextKey. If there's no associated server, or if ErrorLog
// is nil, logging is done via the log package's standard logger.
func logf(r *Request, format string, args ...interface{}) {
s, _ := r.Context().Value(ServerContextKey).(*Server)
if s != nil && s.ErrorLog != nil {
s.ErrorLog.Printf(format, args...)
} else {
log.Printf(format, args...)
}
}
// ListenAndServe listens on the TCP network address addr and then calls
// Serve with handler to handle requests on incoming connections.
// Accepted connections are configured to enable TCP keep-alives.
//
// The handler is typically nil, in which case the DefaultServeMux is used.
//
// ListenAndServe always returns a non-nil error.
func ListenAndServe(addr string, handler Handler) error {
server := &Server{Addr: addr, Handler: handler}
return server.ListenAndServe()
}
// ListenAndServeTLS acts identically to ListenAndServe, except that it
// expects HTTPS connections. Additionally, files containing a certificate and
// matching private key for the server must be provided. If the certificate
// is signed by a certificate authority, the certFile should be the concatenation
// of the server's certificate, any intermediates, and the CA's certificate.
func ListenAndServeTLS(addr, certFile, keyFile string, handler Handler) error {
server := &Server{Addr: addr, Handler: handler}
return server.ListenAndServeTLS(certFile, keyFile)
}
// ListenAndServeTLS listens on the TCP network address srv.Addr and
// then calls ServeTLS to handle requests on incoming TLS connections.
// Accepted connections are configured to enable TCP keep-alives.
//
// Filenames containing a certificate and matching private key for the
// server must be provided if neither the Server's TLSConfig.Certificates
// nor TLSConfig.GetCertificate are populated. If the certificate is
// signed by a certificate authority, the certFile should be the
// concatenation of the server's certificate, any intermediates, and
// the CA's certificate.
//
// If srv.Addr is blank, ":https" is used.
//
// ListenAndServeTLS always returns a non-nil error. After Shutdown or
// Close, the returned error is ErrServerClosed.
func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error {
if srv.shuttingDown() {
return ErrServerClosed
}
addr := srv.Addr
if addr == "" {
addr = ":https"
}
ln, err := net.Listen("tcp", addr)
if err != nil {
return err
}
defer ln.Close()
return srv.ServeTLS(ln, certFile, keyFile)
}
// setupHTTP2_ServeTLS conditionally configures HTTP/2 on
// srv and reports whether there was an error setting it up. If it is
// not configured for policy reasons, nil is returned.
func (srv *Server) setupHTTP2_ServeTLS() error {
srv.nextProtoOnce.Do(srv.onceSetNextProtoDefaults)
return srv.nextProtoErr
}
// setupHTTP2_Serve is called from (*Server).Serve and conditionally
// configures HTTP/2 on srv using a more conservative policy than
// setupHTTP2_ServeTLS because Serve is called after tls.Listen,
// and may be called concurrently. See shouldConfigureHTTP2ForServe.
//
// The tests named TestTransportAutomaticHTTP2* and
// TestConcurrentServerServe in server_test.go demonstrate some
// of the supported use cases and motivations.
func (srv *Server) setupHTTP2_Serve() error {
srv.nextProtoOnce.Do(srv.onceSetNextProtoDefaults_Serve)
return srv.nextProtoErr
}
func (srv *Server) onceSetNextProtoDefaults_Serve() {
if srv.shouldConfigureHTTP2ForServe() {
srv.onceSetNextProtoDefaults()
}
}
// onceSetNextProtoDefaults configures HTTP/2, if the user hasn't
// configured otherwise. (by setting srv.TLSNextProto non-nil)
// It must only be called via srv.nextProtoOnce (use srv.setupHTTP2_*).
func (srv *Server) onceSetNextProtoDefaults() {
if omitBundledHTTP2 || strings.Contains(os.Getenv("GODEBUG"), "http2server=0") {
return
}
// Enable HTTP/2 by default if the user hasn't otherwise
// configured their TLSNextProto map.
if srv.TLSNextProto == nil {
conf := &http2Server{
NewWriteScheduler: func() http2WriteScheduler { return http2NewPriorityWriteScheduler(nil) },
}
srv.nextProtoErr = http2ConfigureServer(srv, conf)
}
}
// TimeoutHandler returns a Handler that runs h with the given time limit.
//
// The new Handler calls h.ServeHTTP to handle each request, but if a
// call runs for longer than its time limit, the handler responds with
// a 503 Service Unavailable error and the given message in its body.
// (If msg is empty, a suitable default message will be sent.)
// After such a timeout, writes by h to its ResponseWriter will return
// ErrHandlerTimeout.
//
// TimeoutHandler supports the Pusher interface but does not support
// the Hijacker or Flusher interfaces.
func TimeoutHandler(h Handler, dt time.Duration, msg string) Handler {
return &timeoutHandler{
handler: h,
body: msg,
dt: dt,
}
}
// ErrHandlerTimeout is returned on ResponseWriter Write calls
// in handlers which have timed out.
var ErrHandlerTimeout = errors.New("http: Handler timeout")
type timeoutHandler struct {
handler Handler
body string
dt time.Duration
// When set, no context will be created and this context will
// be used instead.
testContext context.Context
}
func (h *timeoutHandler) errorBody() string {
if h.body != "" {
return h.body
}
return "<html><head><title>Timeout</title></head><body><h1>Timeout</h1></body></html>"
}
func (h *timeoutHandler) ServeHTTP(w ResponseWriter, r *Request) {
ctx := h.testContext
if ctx == nil {
var cancelCtx context.CancelFunc
ctx, cancelCtx = context.WithTimeout(r.Context(), h.dt)
defer cancelCtx()
}
r = r.WithContext(ctx)
done := make(chan struct{})
tw := &timeoutWriter{
w: w,
h: make(Header),
req: r,
}
panicChan := make(chan interface{}, 1)
go func() {
defer func() {
if p := recover(); p != nil {
panicChan <- p
}
}()
h.handler.ServeHTTP(tw, r)
close(done)
}()
select {
case p := <-panicChan:
panic(p)
case <-done:
tw.mu.Lock()
defer tw.mu.Unlock()
dst := w.Header()
for k, vv := range tw.h {
dst[k] = vv
}
if !tw.wroteHeader {
tw.code = StatusOK
}
w.WriteHeader(tw.code)
w.Write(tw.wbuf.Bytes())
case <-ctx.Done():
tw.mu.Lock()
defer tw.mu.Unlock()
w.WriteHeader(StatusServiceUnavailable)
io.WriteString(w, h.errorBody())
tw.timedOut = true
}
}
type timeoutWriter struct {
w ResponseWriter
h Header
wbuf bytes.Buffer
req *Request
mu sync.Mutex
timedOut bool
wroteHeader bool
code int
}
var _ Pusher = (*timeoutWriter)(nil)
// Push implements the Pusher interface.
func (tw *timeoutWriter) Push(target string, opts *PushOptions) error {
if pusher, ok := tw.w.(Pusher); ok {
return pusher.Push(target, opts)
}
return ErrNotSupported
}
func (tw *timeoutWriter) Header() Header { return tw.h }
func (tw *timeoutWriter) Write(p []byte) (int, error) {
tw.mu.Lock()
defer tw.mu.Unlock()
if tw.timedOut {
return 0, ErrHandlerTimeout
}
if !tw.wroteHeader {
tw.writeHeaderLocked(StatusOK)
}
return tw.wbuf.Write(p)
}
func (tw *timeoutWriter) writeHeaderLocked(code int) {
checkWriteHeaderCode(code)
switch {
case tw.timedOut:
return
case tw.wroteHeader:
if tw.req != nil {
caller := relevantCaller()
logf(tw.req, "http: superfluous response.WriteHeader call from %s (%s:%d)", caller.Function, path.Base(caller.File), caller.Line)
}
default:
tw.wroteHeader = true
tw.code = code
}
}
func (tw *timeoutWriter) WriteHeader(code int) {
tw.mu.Lock()
defer tw.mu.Unlock()
tw.writeHeaderLocked(code)
}
// onceCloseListener wraps a net.Listener, protecting it from
// multiple Close calls.
type onceCloseListener struct {
net.Listener
once sync.Once
closeErr error
}
func (oc *onceCloseListener) Close() error {
oc.once.Do(oc.close)
return oc.closeErr
}
func (oc *onceCloseListener) close() { oc.closeErr = oc.Listener.Close() }
// globalOptionsHandler responds to "OPTIONS *" requests.
type globalOptionsHandler struct{}
func (globalOptionsHandler) ServeHTTP(w ResponseWriter, r *Request) {
w.Header().Set("Content-Length", "0")
if r.ContentLength != 0 {
// Read up to 4KB of OPTIONS body (as mentioned in the
// spec as being reserved for future use), but anything
// over that is considered a waste of server resources
// (or an attack) and we abort and close the connection,
// courtesy of MaxBytesReader's EOF behavior.
mb := MaxBytesReader(w, r.Body, 4<<10)
io.Copy(io.Discard, mb)
}
}
// initALPNRequest is an HTTP handler that initializes certain
// uninitialized fields in its *Request. Such partially-initialized
// Requests come from ALPN protocol handlers.
type initALPNRequest struct {
ctx context.Context
c *tls.Conn
h serverHandler
}
// BaseContext is an exported but unadvertised http.Handler method
// recognized by x/net/http2 to pass down a context; the TLSNextProto
// API predates context support so we shoehorn through the only
// interface we have available.
func (h initALPNRequest) BaseContext() context.Context { return h.ctx }
func (h initALPNRequest) ServeHTTP(rw ResponseWriter, req *Request) {
if req.TLS == nil {
req.TLS = &tls.ConnectionState{}
*req.TLS = h.c.ConnectionState()
}
if req.Body == nil {
req.Body = NoBody
}
if req.RemoteAddr == "" {
req.RemoteAddr = h.c.RemoteAddr().String()
}
h.h.ServeHTTP(rw, req)
}
// loggingConn is used for debugging.
type loggingConn struct {
name string
net.Conn
}
var (
uniqNameMu sync.Mutex
uniqNameNext = make(map[string]int)
)
func newLoggingConn(baseName string, c net.Conn) net.Conn {
uniqNameMu.Lock()
defer uniqNameMu.Unlock()
uniqNameNext[baseName]++
return &loggingConn{
name: fmt.Sprintf("%s-%d", baseName, uniqNameNext[baseName]),
Conn: c,
}
}
func (c *loggingConn) Write(p []byte) (n int, err error) {
log.Printf("%s.Write(%d) = ....", c.name, len(p))
n, err = c.Conn.Write(p)
log.Printf("%s.Write(%d) = %d, %v", c.name, len(p), n, err)
return
}
func (c *loggingConn) Read(p []byte) (n int, err error) {
log.Printf("%s.Read(%d) = ....", c.name, len(p))
n, err = c.Conn.Read(p)
log.Printf("%s.Read(%d) = %d, %v", c.name, len(p), n, err)
return
}
func (c *loggingConn) Close() (err error) {
log.Printf("%s.Close() = ...", c.name)
err = c.Conn.Close()
log.Printf("%s.Close() = %v", c.name, err)
return
}
// checkConnErrorWriter writes to c.rwc and records any write errors to c.werr.
// It only contains one field (and a pointer field at that), so it
// fits in an interface value without an extra allocation.
type checkConnErrorWriter struct {
c *conn
}
func (w checkConnErrorWriter) Write(p []byte) (n int, err error) {
n, err = w.c.rwc.Write(p)
if err != nil && w.c.werr == nil {
w.c.werr = err
w.c.cancelCtx()
}
return
}
func numLeadingCRorLF(v []byte) (n int) {
for _, b := range v {
if b == '\r' || b == '\n' {
n++
continue
}
break
}
return
}
func strSliceContains(ss []string, s string) bool {
for _, v := range ss {
if v == s {
return true
}
}
return false
}
// tlsRecordHeaderLooksLikeHTTP reports whether a TLS record header
// looks like it might've been a misdirected plaintext HTTP request.
func tlsRecordHeaderLooksLikeHTTP(hdr [5]byte) bool {
switch string(hdr[:]) {
case "GET /", "HEAD ", "POST ", "PUT /", "OPTIO":
return true
}
return false
}
|