/*
* 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;
}