JsonUriHandler.cxx

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// JsonUriHandler.cxx -- json interface to the property tree
//
// Written by Torsten Dreyer, started April 2014.
//
// Copyright (C) 2014  Torsten Dreyer
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 
#include "JsonUriHandler.hxx"
#include "jsonprops.hxx"
#include <Main/fg_props.hxx>
 
using std::string;
 
namespace flightgear {
namespace http {
 
bool JsonUriHandler::handleRequest( const HTTPRequest & request, HTTPResponse & response, Connection * connection )
{
  response.Header["Content-Type"] = "application/json; charset=UTF-8";
  response.Header["Access-Control-Allow-Origin"] = "*";
  response.Header["Access-Control-Allow-Methods"] = "OPTIONS, GET, POST";
  response.Header["Access-Control-Allow-Headers"] = "Origin, Accept, Content-Type, X-Requested-With, X-CSRF-Token";
 
  if( request.Method == "OPTIONS" ){
      return true; // OPTIONS only needs the headers
  }
 
  if( request.Method == "GET" ){
 
    // max recursion depth
    int  depth = atoi(request.RequestVariables.get("d").c_str());
    if( depth < 1 ) depth = 1; // at least one level 
 
    // pretty print (y) or compact print (default)
    bool indent = request.RequestVariables.get("i") == "y";
    bool timestamp = request.RequestVariables.get("t") == "y";
 
    SGPropertyNode_ptr node = getRequestedNode(request );
    if( !node.valid() ) {
      response.StatusCode = 404;
      response.Content = "{}";
      return true;
    } 
 
    response.Content = JSON::toJsonString( indent, node, depth, timestamp ? fgGetDouble("/sim/time/elapsed-sec") : -1.0 );
 
    return true;
  }
 
  if( request.Method == "POST" ) {
    SGPropertyNode_ptr node = getRequestedNode(request );
    if( !node.valid() ) {
      response.StatusCode = 404;
      response.Content = "{}";
      return true;
    } 
 
    SG_LOG(SG_NETWORK,SG_INFO, "JsonUriHandler: setting property from'" << request.Content << "'" );
    cJSON * json = cJSON_Parse( request.Content.c_str() );
    if( NULL != json ) {
      JSON::toProp( json, node );
      cJSON_Delete(json);
    }
 
    response.Content = "{}";
    return true;
  }
 
  SG_LOG(SG_NETWORK,SG_INFO, "JsonUriHandler: invalid request method '" << request.Method << "'" );
  response.Header["Allow"] = "OPTIONS, GET, POST";
  response.StatusCode = 405;
  response.Content = "{}";
  return true; 
 
}
 
SGPropertyNode_ptr JsonUriHandler::getRequestedNode(const HTTPRequest & request)
{
  SG_LOG(SG_NETWORK,SG_INFO, "JsonUriHandler: request is '" << request.Uri << "'" );
  string propertyPath = request.Uri;
  propertyPath = propertyPath.substr( getUri().size() );
 
  // skip trailing '/' - not very efficient but shouldn't happen too often
  while( !propertyPath.empty() && propertyPath[ propertyPath.length()-1 ] == '/' )
    propertyPath = propertyPath.substr(0,propertyPath.length()-1);
 
  SGPropertyNode_ptr reply = fgGetNode( string("/") + propertyPath );
  if( !reply.valid() ) {
    SG_LOG(SG_NETWORK,SG_WARN, "JsonUriHandler: requested node not found: '" << propertyPath << "'");
  }
  return reply;
}
 
 
} // namespace http
} // namespace flightgear