view src/http/modules/ngx_http_empty_gif_module.c @ 7355:b64adc956643

Rewrite: removed r->err_status special handling (ticket #1634). Trying to look into r->err_status in the "return" directive makes it behave differently than real errors generated in other parts of the code, and is an endless source of various problems. This behaviour was introduced in 726:7b71936d5299 (0.4.4) with the comment "fix: "return" always overrode "error_page" response code". It is not clear if there were any real cases this was expected to fix, but there are several cases which are broken due to this change, some previously fixed (4147:7f64de1cc2c0). In ticket #1634, the problem is that when r->err_status is set to a non-special status code, it is not possible to return a response by simply returning r->err_status. If this is the case, the only option is to return script's e->status instead. An example configuration: location / { error_page 404 =200 /err502; return 404; } location = /err502 { return 502; } After the change, such a configuration will properly return standard 502 error, much like it happens when a 502 error is generated by proxy_pass. This also fixes the following configuration to properly close connection as clearly requested by "return 444": location / { error_page 404 /close; return 404; } location = /close { return 444; } Previously, this required "error_page 404 = /close;" to work as intended.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 21 Sep 2018 15:59:33 +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;
}