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) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_DLOPEN_H_INCLUDED_
#define _NGX_DLOPEN_H_INCLUDED_


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


#define NGX_HAVE_DLOPEN  1


#define ngx_dlopen(path)           LoadLibrary((char *) path)
#define ngx_dlopen_n               "LoadLibrary()"

#define ngx_dlsym(handle, symbol)  (void *) GetProcAddress(handle, symbol)
#define ngx_dlsym_n                "GetProcAddress()"

#define ngx_dlclose(handle)        (FreeLibrary(handle) ? 0 : -1)
#define ngx_dlclose_n              "FreeLibrary()"


char *ngx_dlerror(void);


#endif /* _NGX_DLOPEN_H_INCLUDED_ */