Mercurial > hg > nginx
view src/http/modules/ngx_http_empty_gif_module.c @ 7235:c2a0a838c40f
gRPC: special handling of "trailer only" responses.
The gRPC protocol makes a distinction between HEADERS frame with
the END_STREAM flag set, and a HEADERS frame followed by an empty
DATA frame with the END_STREAM flag. The latter is not permitted,
and results in errors not being propagated through nginx. Instead,
gRPC clients complain that "server closed the stream without sending
trailers" (seen in grpc-go) or "13: Received RST_STREAM with error
code 2" (seen in grpc-c).
To fix this, nginx now returns HEADERS with the END_STREAM flag if
the response length is known to be 0, and we are not expecting
any trailer headers to be added. And the response length is
explicitly set to 0 in the gRPC proxy if we see initial HEADERS frame
with the END_STREAM flag set.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sat, 17 Mar 2018 23:04:26 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static char *ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_empty_gif_commands[] = { { ngx_string("empty_gif"), NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS, ngx_http_empty_gif, 0, 0, NULL }, ngx_null_command }; /* the minimal single pixel transparent GIF, 43 bytes */ static u_char ngx_empty_gif[] = { 'G', 'I', 'F', '8', '9', 'a', /* header */ /* logical screen descriptor */ 0x01, 0x00, /* logical screen width */ 0x01, 0x00, /* logical screen height */ 0x80, /* global 1-bit color table */ 0x01, /* background color #1 */ 0x00, /* no aspect ratio */ /* global color table */ 0x00, 0x00, 0x00, /* #0: black */ 0xff, 0xff, 0xff, /* #1: white */ /* graphic control extension */ 0x21, /* extension introducer */ 0xf9, /* graphic control label */ 0x04, /* block size */ 0x01, /* transparent color is given, */ /* no disposal specified, */ /* user input is not expected */ 0x00, 0x00, /* delay time */ 0x01, /* transparent color #1 */ 0x00, /* block terminator */ /* image descriptor */ 0x2c, /* image separator */ 0x00, 0x00, /* image left position */ 0x00, 0x00, /* image top position */ 0x01, 0x00, /* image width */ 0x01, 0x00, /* image height */ 0x00, /* no local color table, no interlaced */ /* table based image data */ 0x02, /* LZW minimum code size, */ /* must be at least 2-bit */ 0x02, /* block size */ 0x4c, 0x01, /* compressed bytes 01_001_100, 0000000_1 */ /* 100: clear code */ /* 001: 1 */ /* 101: end of information code */ 0x00, /* block terminator */ 0x3B /* trailer */ }; static ngx_http_module_t ngx_http_empty_gif_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_empty_gif_module = { NGX_MODULE_V1, &ngx_http_empty_gif_module_ctx, /* module context */ ngx_http_empty_gif_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_str_t ngx_http_gif_type = ngx_string("image/gif"); static ngx_int_t ngx_http_empty_gif_handler(ngx_http_request_t *r) { ngx_http_complex_value_t cv; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } ngx_memzero(&cv, sizeof(ngx_http_complex_value_t)); cv.value.len = sizeof(ngx_empty_gif); cv.value.data = ngx_empty_gif; r->headers_out.last_modified_time = 23349600; return ngx_http_send_response(r, NGX_HTTP_OK, &ngx_http_gif_type, &cv); } static char * ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_empty_gif_handler; return NGX_CONF_OK; }