external_url_fetcher.h

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/*
 * Copyright 2010 Google Inc.
 *
 * Licensed 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 NET_INSTAWEB_HTTP_PUBLIC_EXTERNAL_URL_FETCHER_H_
#define NET_INSTAWEB_HTTP_PUBLIC_EXTERNAL_URL_FETCHER_H_

#include "net/instaweb/http/public/url_async_fetcher.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

class AsyncFetch;
class MessageHandler;
class RequestHeaders;


class ExternalUrlFetcher : public UrlAsyncFetcher {
 public:
  ExternalUrlFetcher() {}
  virtual ~ExternalUrlFetcher() {}

  virtual void Fetch(const GoogleString& url,
                     MessageHandler* message_handler,
                     AsyncFetch* fetch);

  static const char kDefaultUserAgent[];

  void set_binary(const GoogleString& binary);


 protected:
  virtual void AppendHeaders(const RequestHeaders& request_headers,
                             StringVector* escaped_headers);

  GoogleString binary_;

 private:
  virtual const char* GetFetchLabel() = 0;

  virtual GoogleString ConstructFetchCommand(
      const GoogleString& escaped_url,
      const char* user_agent,
      const StringVector& escaped_headers) = 0;

  
};

}  

#endif