nginx 0.7.65 *) Security: now nginx/Windows ignores trailing spaces in URI. Thanks to Dan Crowley, Core Security Technologies. *) Security: now nginx/Windows ignores short files names. Thanks to Dan Crowley, Core Security Technologies. *) Change: now the "009" status code is written to an access log for proxied HTTP/0.9 responses. *) Change: now the default buffer size of the "large_client_header_buffers" directive is 8K. Thanks to Andrew Cholakian. *) Change: now default SSL ciphers are "HIGH:!ADH:!MD5". *) Change: now SSLv2 protocol is disabled by default. *) Change: now $host variable value is always low case. *) Feature: the conf/fastcgi.conf for simple FastCGI configurations. *) Feature: now URI part is not required a "proxy_pass" directive if variables are used. *) Feature: the $ssl_session_id variable. *) Bugfix: if a proxied or FastCGI request was internally redirected to another proxied or FastCGI location, then $upstream_response_time variable may have abnormally large value; the bug had appeared in 0.7.63. *) Bugfix: if the "expires modified" set date in the past, then a negative number was set in the "Cache-Control" response header line. Thanks to Alex Kapranoff. *) Bugfix: nginx closed a connection if a cached response had an empty body. Thanks to Piotr Sikora. *) Bugfix: nginx cached a 304 response if there was the "If-None-Match" header line in a proxied request. Thanks to Tim Dettrick and David Kostal. *) Bugfix: nginx did not treat a comma as separator in the "Cache-Control" backend response header line. *) Bugfix: cached HTTP/0.9 responses were handled incorrectly. *) Bugfix: nginx sent gzipped responses to clients those do not support gzip, if "gzip_static on" and "gzip_vary off"; the bug had appeared in 0.8.16. *) Bugfix: nginx always added "Content-Encoding: gzip" response header line in 304 responses sent by ngx_http_gzip_static_module. *) Bugfix: the "!-x" operator did not work. Thanks to Maxim Dounin. *) Bugfix: a segmentation fault might occur in a worker process, if limit_rate was used in HTTPS server. Thanks to Maxim Dounin. *) Bugfix: a segmentation fault might occur in a worker process while $limit_rate logging. Thanks to Maxim Dounin. *) Bugfix: nginx did not support dates in 2038 year on 32-bit platforms; *) Bugfix: nginx/Windows tried to delete a temporary file twice if the file should replace an already existent file. *) Bugfix: nginx/Windows tried to rename a temporary file twice if the file should replace an already existent file. *) Bugfix: nginx/Windows might not create temporary file, a cache file, or "proxy/fastcgi_store"d file if a worker had no enough access rights for top level directories. *) Bugfix: in UTF-8 encoding support by "try_files" directive in nginx/Windows. *) Bugfix: UTF-8 encoding usage in the ngx_http_autoindex_module. Thanks to Maxim Dounin. *) Bugfix: the ngx_http_autoindex_module did not show the trailing slash in links to a directory; the bug had appeared in 0.7.15. *) Bugfix: nginx did not close a log file set by the --error-log-path configuration option; the bug had appeared in 0.7.53. *) Bugfix: "addition_types" directive was incorrectly named "addtion_types". *) Bugfix: invalid request line in $request variable was written in access_log only if error_log was set to "info" or "debug" level.

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>



static ngx_int_t ngx_http_not_modified_filter_init(ngx_conf_t *cf);


static ngx_http_module_t  ngx_http_not_modified_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_not_modified_filter_init,     /* 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_not_modified_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_not_modified_filter_module_ctx, /* module context */
    NULL,                                  /* 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_http_output_header_filter_pt  ngx_http_next_header_filter;


static ngx_int_t
ngx_http_not_modified_header_filter(ngx_http_request_t *r)
{
    time_t                     ims;
    ngx_http_core_loc_conf_t  *clcf;

    if (r->headers_out.status != NGX_HTTP_OK
        || r != r->main
        || r->headers_in.if_modified_since == NULL
        || r->headers_out.last_modified_time == -1)
    {
        return ngx_http_next_header_filter(r);
    }

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    if (clcf->if_modified_since == NGX_HTTP_IMS_OFF) {
        return ngx_http_next_header_filter(r);
    }

    ims = ngx_http_parse_time(r->headers_in.if_modified_since->value.data,
                              r->headers_in.if_modified_since->value.len);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http ims:%d lm:%d", ims, r->headers_out.last_modified_time);

    if (ims != r->headers_out.last_modified_time) {

        if (clcf->if_modified_since == NGX_HTTP_IMS_EXACT
            || ims < r->headers_out.last_modified_time)
        {
            return ngx_http_next_header_filter(r);
        }
    }

    r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
    r->headers_out.status_line.len = 0;
    r->headers_out.content_type.len = 0;
    ngx_http_clear_content_length(r);
    ngx_http_clear_accept_ranges(r);

    if (r->headers_out.content_encoding) {
        r->headers_out.content_encoding->hash = 0;
        r->headers_out.content_encoding = NULL;
    }

    return ngx_http_next_header_filter(r);
}


static ngx_int_t
ngx_http_not_modified_filter_init(ngx_conf_t *cf)
{
    ngx_http_next_header_filter = ngx_http_top_header_filter;
    ngx_http_top_header_filter = ngx_http_not_modified_header_filter;

    return NGX_OK;
}