| |
| /* |
| * Copyright (C) Igor Sysoev |
| */ |
| |
| #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 */ |
| }; |
| |
| |
| 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_int_t |
| ngx_http_empty_gif_handler(ngx_http_request_t *r) |
| { |
| ngx_int_t rc; |
| ngx_buf_t *b; |
| ngx_chain_t out; |
| |
| if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { |
| return NGX_HTTP_NOT_ALLOWED; |
| } |
| |
| rc = ngx_http_discard_body(r); |
| |
| if (rc != NGX_OK && rc != NGX_AGAIN) { |
| return rc; |
| } |
| |
| r->headers_out.content_type.len = sizeof("image/gif") - 1; |
| r->headers_out.content_type.data = (u_char *) "image/gif"; |
| |
| if (r->method == NGX_HTTP_HEAD) { |
| r->headers_out.status = NGX_HTTP_OK; |
| |
| rc = ngx_http_send_header(r); |
| |
| if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { |
| return rc; |
| } |
| } |
| |
| b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t)); |
| if (b == NULL) { |
| return NGX_HTTP_INTERNAL_SERVER_ERROR; |
| } |
| |
| out.buf = b; |
| out.next = NULL; |
| |
| b->pos = ngx_empty_gif; |
| b->last = ngx_empty_gif + sizeof(ngx_empty_gif); |
| b->memory = 1; |
| b->last_buf = 1; |
| |
| r->headers_out.status = NGX_HTTP_OK; |
| r->headers_out.content_length_n = sizeof(ngx_empty_gif); |
| r->headers_out.last_modified_time = 23349600; |
| |
| rc = ngx_http_send_header(r); |
| |
| if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { |
| return rc; |
| } |
| |
| return ngx_http_output_filter(r, &out);; |
| } |
| |
| |
| 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; |
| } |