webserver.h

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// Copyright 2012 Cloudera 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 IMPALA_UTIL_WEBSERVER_H
#define IMPALA_UTIL_WEBSERVER_H

#include <squeasel/squeasel.h>
#include <string>
#include <map>
#include <boost/function.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <rapidjson/document.h>

#include "common/status.h"
#include "util/network-util.h"

namespace impala {

class Webserver {
 public:
  typedef std::map<std::string, std::string> ArgumentMap;
  typedef boost::function<void (const ArgumentMap& args, rapidjson::Document* json)>
      UrlCallback;

  static const char* ENABLE_RAW_JSON_KEY;

  Webserver(const int port);

  Webserver();

  ~Webserver();

  Status Start();

  void Stop();

  //
  //
  void RegisterUrlCallback(const std::string& path, const std::string& template_filename,
      const UrlCallback& callback, bool is_on_nav_bar = true);

  const TNetworkAddress& http_address() { return http_address_; }

  bool IsSecure() const;

 private:
  class UrlHandler {
   public:
    UrlHandler(const UrlCallback& cb, const std::string& template_filename,
        bool is_on_nav_bar)
        : is_on_nav_bar_(is_on_nav_bar), template_callback_(cb),
          template_filename_(template_filename) { }

    bool is_on_nav_bar() const { return is_on_nav_bar_; }
    const UrlCallback& callback() const { return template_callback_; }
    const std::string& template_filename() const { return template_filename_; }

   private:
    bool is_on_nav_bar_;

    UrlCallback template_callback_;

    std::string template_filename_;
  };

  static int LogMessageCallbackStatic(const struct sq_connection* connection,
      const char* message);

  static int BeginRequestCallbackStatic(struct sq_connection* connection);

  int BeginRequestCallback(struct sq_connection* connection,
      struct sq_request_info* request_info);

  void RootHandler(const ArgumentMap& args, rapidjson::Document* document);

  void ErrorHandler(const ArgumentMap& args, rapidjson::Document* document);

  void BuildArgumentMap(const std::string& args, ArgumentMap* output);

  void GetCommonJson(rapidjson::Document* document);

  boost::shared_mutex url_handlers_lock_;

  typedef std::map<std::string, UrlHandler> UrlHandlerMap;
  UrlHandlerMap url_handlers_;

  TNetworkAddress http_address_;

  struct sq_context* context_;

  UrlHandler error_handler_;
};

}

#endif // IMPALA_UTIL_WEBSERVER_H