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nginx / nginx / 055c4600306f0ad53e8679c7f60af644e6df3026 / . / src / http / modules / ngx_http_empty_gif_module.c
blob: 04114dc3f415d160088807eb331a7d9f6712524e [file] [log] [blame]
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]1
2/*
3 * Copyright (C) Igor Sysoev
Maxim Konovalovf8d59e32012-01-18 15:07:43 +0000[diff] [blame]4 * Copyright (C) Nginx, Inc.
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]5 */
6
7#include <ngx_config.h>
8#include <ngx_core.h>
9#include <ngx_http.h>
10
11
12static char *ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd,
13 void *conf);
14
15static ngx_command_t ngx_http_empty_gif_commands[] = {
16
17 { ngx_string("empty_gif"),
18 NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
19 ngx_http_empty_gif,
20 0,
21 0,
22 NULL },
23
24 ngx_null_command
25};
26
27
28/* the minimal single pixel transparent GIF, 43 bytes */
29
30static u_char ngx_empty_gif[] = {
31
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]32 'G', 'I', 'F', '8', '9', 'a', /* header */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]33
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]34 /* logical screen descriptor */
35 0x01, 0x00, /* logical screen width */
36 0x01, 0x00, /* logical screen height */
37 0x80, /* global 1-bit color table */
38 0x01, /* background color #1 */
39 0x00, /* no aspect ratio */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]40
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]41 /* global color table */
42 0x00, 0x00, 0x00, /* #0: black */
43 0xff, 0xff, 0xff, /* #1: white */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]44
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]45 /* graphic control extension */
46 0x21, /* extension introducer */
47 0xf9, /* graphic control label */
48 0x04, /* block size */
49 0x01, /* transparent color is given, */
50 /* no disposal specified, */
51 /* user input is not expected */
52 0x00, 0x00, /* delay time */
53 0x01, /* transparent color #1 */
54 0x00, /* block terminator */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]55
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]56 /* image descriptor */
57 0x2c, /* image separator */
58 0x00, 0x00, /* image left position */
59 0x00, 0x00, /* image top position */
60 0x01, 0x00, /* image width */
61 0x01, 0x00, /* image height */
62 0x00, /* no local color table, no interlaced */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]63
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]64 /* table based image data */
65 0x02, /* LZW minimum code size, */
66 /* must be at least 2-bit */
67 0x02, /* block size */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]68 0x4c, 0x01, /* compressed bytes 01_001_100, 0000000_1 */
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]69 /* 100: clear code */
70 /* 001: 1 */
71 /* 101: end of information code */
72 0x00, /* block terminator */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]73
Igor Sysoevc31a9bb2005-11-26 10:11:11 +0000[diff] [blame]74 0x3B /* trailer */
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]75};
76
77
Igor Sysoev8f125582006-07-28 15:16:17 +0000[diff] [blame]78static ngx_http_module_t ngx_http_empty_gif_module_ctx = {
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]79 NULL, /* preconfiguration */
80 NULL, /* postconfiguration */
81
82 NULL, /* create main configuration */
83 NULL, /* init main configuration */
84
85 NULL, /* create server configuration */
86 NULL, /* merge server configuration */
87
88 NULL, /* create location configuration */
89 NULL /* merge location configuration */
90};
91
92
93ngx_module_t ngx_http_empty_gif_module = {
94 NGX_MODULE_V1,
95 &ngx_http_empty_gif_module_ctx, /* module context */
96 ngx_http_empty_gif_commands, /* module directives */
97 NGX_HTTP_MODULE, /* module type */
98 NULL, /* init master */
99 NULL, /* init module */
100 NULL, /* init process */
101 NULL, /* init thread */
102 NULL, /* exit thread */
103 NULL, /* exit process */
104 NULL, /* exit master */
105 NGX_MODULE_V1_PADDING
106};
107
108
Igor Sysoev082d9962010-06-18 15:17:07 +0000[diff] [blame]109static ngx_str_t ngx_http_gif_type = ngx_string("image/gif");
110
111
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]112static ngx_int_t
113ngx_http_empty_gif_handler(ngx_http_request_t *r)
114{
Igor Sysoev082d9962010-06-18 15:17:07 +0000[diff] [blame]115 ngx_http_complex_value_t cv;
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]116
Igor Sysoevac72bd12006-05-04 15:32:46 +0000[diff] [blame]117 if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) {
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]118 return NGX_HTTP_NOT_ALLOWED;
119 }
120
Igor Sysoev082d9962010-06-18 15:17:07 +0000[diff] [blame]121 ngx_memzero(&cv, sizeof(ngx_http_complex_value_t));
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]122
Igor Sysoev082d9962010-06-18 15:17:07 +0000[diff] [blame]123 cv.value.len = sizeof(ngx_empty_gif);
124 cv.value.data = ngx_empty_gif;
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]125 r->headers_out.last_modified_time = 23349600;
126
Igor Sysoev082d9962010-06-18 15:17:07 +0000[diff] [blame]127 return ngx_http_send_response(r, NGX_HTTP_OK, &ngx_http_gif_type, &cv);
Igor Sysoev0e5dc5c2005-11-15 13:30:52 +0000[diff] [blame]128}
129
130
131static char *
132ngx_http_empty_gif(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
133{
134 ngx_http_core_loc_conf_t *clcf;
135
136 clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
137 clcf->handler = ngx_http_empty_gif_handler;
138
139 return NGX_CONF_OK;
140}