qgsremotedatasourcebuilder.cpp

/***************************************************************************
                              qgsremotedatasourcebuilder.cpp
                              ------------------------------
  begin                : July, 2008
  copyright            : (C) 2008 by Marco Hugentobler
  email                : marco dot hugentobler at karto dot baug dot ethz dot ch
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/

#include "qgsremotedatasourcebuilder.h"
#include "qgsftptransaction.h"
#include "qgshttptransaction.h"
#include "qgslogger.h"
#include "qgsrasterlayer.h"
#include "qgsvectorlayer.h"
#include <QDomElement>
#include <QFile>
#include <QTemporaryFile>

QgsRemoteDataSourceBuilder::QgsRemoteDataSourceBuilder(): QgsMSLayerBuilder()
{

}

QgsRemoteDataSourceBuilder::~QgsRemoteDataSourceBuilder()
{

}

QgsMapLayer* QgsRemoteDataSourceBuilder::createMapLayer( const QDomElement& elem, const QString& layerName, QList<QTemporaryFile*>& filesToRemove, QList<QgsMapLayer*>& layersToRemove, bool allowCaching ) const
{
  QgsDebugMsg( "entering." );
  QgsMapLayer* theLayer = 0;
  if ( elem.tagName() == "RemoteRDS" )
  {
    theLayer = rasterLayerFromRemoteRDS( elem, layerName, filesToRemove, layersToRemove, allowCaching );
  }
  else if ( elem.tagName() == "RemoteVDS" )
  {
    theLayer = vectorLayerFromRemoteVDS( elem, layerName, filesToRemove, layersToRemove, allowCaching );
  }
  else
  {
    return 0;
  }
  return theLayer;
}

QgsRasterLayer* QgsRemoteDataSourceBuilder::rasterLayerFromRemoteRDS( const QDomElement& remoteRDSElem,
    const QString& layerName,
    QList<QTemporaryFile*> &filesToRemove,
    QList<QgsMapLayer*> &layersToRemove,
    bool allowCaching ) const
{
  Q_UNUSED( layerName );
  Q_UNUSED( allowCaching );
  QgsDebugMsg( "entering." );

  //load file with QgsHttpTransaction or QgsFtpTransaction
  QByteArray fileContents;
  QString uri = remoteRDSElem.text();

  QgsRasterLayer* rl = 0;
  if ( loadData( uri, fileContents ) != 0 )
  {
    return 0;
  }

  QTemporaryFile* tmpFile = new QTemporaryFile();
  if ( tmpFile->open() )
  {
    tmpFile->write( fileContents );
    tmpFile->flush();
  }
  else
  {
    QgsDebugMsg( "Error, creation of temp file failed" );
    delete tmpFile;
    return 0;
  }

  //create rasterlayer
  rl = new QgsRasterLayer( tmpFile->fileName(), layerNameFromUri( tmpFile->fileName() ) );
  layersToRemove.push_back( rl );
  filesToRemove.push_back( tmpFile );
  clearRasterSymbology( rl );
  return rl;
}

QgsVectorLayer* QgsRemoteDataSourceBuilder::vectorLayerFromRemoteVDS( const QDomElement& remoteVDSElem,
    const QString& layerName,
    QList<QTemporaryFile*>& filesToRemove,
    QList<QgsMapLayer*>& layersToRemove,
    bool allowCaching ) const
{
  Q_UNUSED( layerName );
  Q_UNUSED( allowCaching );
  QString providerString;
  QString formatString = remoteVDSElem.attribute( "format" );
  if ( formatString.compare( "gml", Qt::CaseInsensitive ) == 0 )
  {
    providerString = "WFS";
  }
  else
  {
    providerString = formatString;
  }

  //load file with QgsHttpTransaction
  QByteArray fileContents;
  QString uri = remoteVDSElem.text();

  QgsVectorLayer* vl = 0;

  if ( loadData( uri, fileContents ) != 0 )
  {
    return 0;
  }

  //store content into temporary file
  QTemporaryFile* tmpFile = new QTemporaryFile();
  if ( tmpFile->open() )
  {
    tmpFile->write( fileContents );
    tmpFile->flush();
  }
  else
  {
    delete tmpFile;
    return 0;
  }

  //create vector layer

  //SOS has a special datasource key...
  if ( formatString.compare( "SOS", Qt::CaseInsensitive ) == 0 )
  {
    QString url = "url=" + tmpFile->fileName() + " method=FILE xml=";
    vl =  new QgsVectorLayer( url, layerNameFromUri( tmpFile->fileName() ), providerString );
  }
  else
  {
    vl =  new QgsVectorLayer( tmpFile->fileName(), layerNameFromUri( tmpFile->fileName() ), providerString );
  }

  if ( !( vl->isValid() ) )
  {
    QgsDebugMsg( "vl is not valid" );
  }

  layersToRemove.push_back( vl );
  filesToRemove.push_back( tmpFile );
  return vl;
}

int QgsRemoteDataSourceBuilder::loadData( const QString& url, QByteArray& data ) const
{
  if ( url.startsWith( "http", Qt::CaseInsensitive ) )
  {
    QgsHttpTransaction http( url );
    if ( !http.getSynchronously( data ) )
    {
      QgsDebugMsg( "Error, loading from http failed" );
      return 1; //no success
    }
  }
  else if ( url.startsWith( "ftp", Qt::CaseInsensitive ) )
  {
    QgsFtpTransaction ftp;
    if ( ftp.get( url, data ) != 0 )
    {
      return 1;
    }
  }
  return 0;
}