pagespeed/apache/header_util.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */


#ifndef PAGESPEED_APACHE_HEADER_UTIL_H_
#define PAGESPEED_APACHE_HEADER_UTIL_H_

#include <cstddef>

#include "pagespeed/kernel/base/callback.h"
#include "pagespeed/kernel/base/string_util.h"

struct request_rec;

namespace net_instaweb {

class RequestHeaders;
class ResponseHeaders;

// Defines a predicate function used to select which request-headers
// to copy.  The callback sets the bool* arg (.second) to true if
// it wants to include the header.
//
// The StringPiece is the name of the header.
typedef Callback2<StringPiece, bool*> HeaderPredicateFn;

// Converts Apache header structure into RequestHeaders, selecting
// only those for which the predicate sets its bool* argument to true.
// If the predicate is NULL, then all the headers are transferred.
//
// The predicate should be created with NewPermanentCallback and stored
// in a scoped_ptr<Callback2>, so that it is deleted after this function
// completes.
void ApacheRequestToRequestHeaders(const request_rec& request,
                                   RequestHeaders* request_headers,
                                   HeaderPredicateFn* predicate);

// Fully converts apache request header structure into RequestHeaders.
inline void ApacheRequestToRequestHeaders(const request_rec& request,
                                          RequestHeaders* request_headers) {
  return ApacheRequestToRequestHeaders(request, request_headers, NULL);
}

// Converts Apache header structure (request.headers_out) into ResponseHeaders
// headers. If err_headers is not NULL then request.err_headers_out is copied
// into it. In the event that headers == err_headers, the headers from
// request.err_headers_out will be appended to the list of headers, but no
// merging occurs.
void ApacheRequestToResponseHeaders(const request_rec& request,
                                    ResponseHeaders* headers,
                                    ResponseHeaders* err_headers);

// Converts the ResponseHeaders to the output headers.  This function
// does not alter the status code or the major/minor version of the
// Apache request.
void ResponseHeadersToApacheRequest(const ResponseHeaders& response_headers,
                                    request_rec* request);

// Converts ResponseHeaders into Apache request err_headers.  This
// function does not alter the status code or the major/minor version
// of the Apache request.
void ErrorHeadersToApacheRequest(const ResponseHeaders& err_response_headers,
                                 request_rec* request);

// Remove downstream filters that might corrupt our caching headers.
void DisableDownstreamHeaderFilters(request_rec* request);

// Debug utility for printing Apache headers to stdout
void PrintHeaders(request_rec* request);

// Get request->headers_out as a string, intended for tests.
GoogleString HeadersOutToString(request_rec* request);

// Get request->subprocess_env as a string, intended for tests.
GoogleString SubprocessEnvToString(request_rec* request);

// Updates headers related to caching (but not Cache-Control).
void DisableCachingRelatedHeaders(request_rec* request);

// Updates caching headers to ensure the resulting response is not cached.
// Removes any max-age specification, and adds max-age=0, no-cache.
void DisableCacheControlHeader(request_rec* request);

}  // namespace net_instaweb

#endif  // PAGESPEED_APACHE_HEADER_UTIL_H_