Upstream: avoid closing client connection in edge case. If proxy_cache is enabled, and proxy_no_cache tests true, it was previously possible for the client connection to be closed after a 304. The fix is to recheck r->header_only after the final cacheability is determined, and end the request if no longer cacheable. Example configuration: proxy_cache foo; proxy_cache_bypass 1; proxy_no_cache 1; If a client sends If-None-Match, and the upstream server returns 200 with a matching ETag, no body should be returned to the client. At the start of ngx_http_upstream_send_response proxy_no_cache is not yet tested, thus cacheable is still 1 and downstream_error is set. However, by the time the downstream_error check is done in process_request, proxy_no_cache has been tested and cacheable is set to 0. The client connection is then closed, regardless of keepalive.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


int ngx_file_type(char *file, ngx_file_info_t *sb)
{
    sb->dwFileAttributes = GetFileAttributes(file);

    if (sb->dwFileAttributes == INVALID_FILE_ATTRIBUTES) {
        return -1;
    }

    return 0;
}

/*
int ngx_stat(char *file, ngx_stat_t *sb)
{
    *sb = GetFileAttributes(file);

    if (*sb == INVALID_FILE_ATTRIBUTES) {
        return -1;
    }

    return 0;
}
*/