BridgeHttpClient.h

/*
  Copyright (c) 2016, 2021 Imre Horvath. All rights reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifndef _BRIDGE_HTTP_CLIENT_H_
#define _BRIDGE_HTTP_CLIENT_H_

#include <Process.h>

class BridgeHttpClient : public Process {

public:
  /*
   * Constructor
   */
  BridgeHttpClient();

  /*
   * Synchronous methods
   */
  void get(const char* url);
  void get(const String& url) {get(url.c_str());}
  void post(const char* url, const char* data);
  void post(const String& url, const char* data) {post(url.c_str(), data);}
  void post(const char* url, const String& data) {post(url, data.c_str());}
  void post(const String& url, const String& data) {post(url.c_str(), data.c_str());}
  void put(const char* url, const char* data);
  void put(const String& url, const char* data) {put(url.c_str(), data);}
  void put(const char* url, const String& data) {put(url, data.c_str());}
  void put(const String& url, const String& data) {put(url.c_str(), data.c_str());}
  void del(const char* url);
  void del(const String& url) {del(url.c_str());}

  /*
   * Asynchronous methods
   */
  void getAsync(const char* url);
  void getAsync(const String& url) {getAsync(url.c_str());}
  void postAsync(const char* url, const char* data);
  void postAsync(const String& url, const char* data) {postAsync(url.c_str(), data);}
  void postAsync(const char* url, const String& data) {postAsync(url, data.c_str());}
  void postAsync(const String& url, const String& data) {postAsync(url.c_str(), data.c_str());}
  void putAsync(const char* url, const char* data);
  void putAsync(const String& url, const char* data) {putAsync(url.c_str(), data);}
  void putAsync(const char* url, const String& data) {putAsync(url, data.c_str());}
  void putAsync(const String& url, const String& data) {putAsync(url.c_str(), data.c_str());}
  void delAsync(const char* url);
  void delAsync(const String& url) {delAsync(url.c_str());}

  /*
   * Method to check, if the async request is still running or has finished.
   */
  bool finished();

  /*
   * Call this method after the request has finished,
   * to get the HTTP response code from the server.
   *
   * Returns the response code eg. 200
   */
  unsigned int getResponseCode();

  /*
   * Call this method after the request has finished,
   * to get the response headers received from the server.
   *
   * Returns a String object with all the response headers included.
   */
  String getResponseHeaders();

  /*
   * Call this method before issuing the requests,
   * to allows "insecure" SSL.
   *
   * Useful in the following case for example:
   * Certificate cannot be authenticated with known CA certificates.
   */
  void enableInsecure();

  /*
   * Call this method before issuing the request,
   * to add an extra header to the request.
   *
   * Returns 0 if the header fits into the array of headers. -1 otherwise.
   */
  int addHeader(const char* header);
  int addHeader(const String& header) {addHeader(header.c_str());}

  /*
   * Call this method before issuing the request,
   * to include basic authorization into the request.
   */
  void basicAuth(const char* user, const char* passwd);
  void basicAuth(const String& user, const char* passwd) {basicAuth(user.c_str(), passwd);}
  void basicAuth(const char* user, const String& passwd) {basicAuth(user, passwd.c_str());}
  void basicAuth(const String& user, const String& passwd) {basicAuth(user.c_str(), passwd.c_str());}

  /*
   * Call this method between the different request calls on the same client,
   * to clear/setup the request headers for the next call.
   */
  void clearHeaders();

  /*
   * Call this method between the different request calls on the same client,
   * to clear the previously set basic authorization for the subsequent call.
   */
  void clearAuth();

  /*
   * Call this method after the request has finished,
   * to get a particular response header value.
   *
   * Returns true and sets the value parameter if found,
   * otherwise return false and doesn't set value parameter at all.
   */
  bool getResponseHeaderValue(const String& header, String& value);

  /*
   * Reset client request settings.
   * Clears the request headers, basic auth. settings and the insecure-enabled flag.
   */
  void startRequest();

private:
  String _tempFileName;

  bool _isInsecureEnabled;

  const char* _user;
  const char* _passwd;

  // The library supports up to 16 user addable request headers
  static const unsigned maxNumberOfExtraHeaders = 16;
  const char* _extraHeaders[maxNumberOfExtraHeaders];
  int _extraHeaderIdx;

  String _cachedRespHeaders;

  /*
   * Sends the actual request via cURL on the Linux side
   */
  void request(const char* verb, const char* url, const char* data, bool async=false);

  /*
   * Clears the cached response headers between subsequent requests
   */
  void clearCachedRespHeaders();
};

#endif