[FEATURE] Download a file in Processing

src/analysis/CMakeLists.txt

@@ -37,6 +37,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmextractbyexpression.cpp
   processing/qgsalgorithmextractbyextent.cpp
   processing/qgsalgorithmextractbylocation.cpp
+  processing/qgsalgorithmfiledownloader.cpp
   processing/qgsalgorithmfixgeometries.cpp
   processing/qgsalgorithmjoinbyattribute.cpp
   processing/qgsalgorithmjoinwithlines.cpp

src/analysis/processing/qgsalgorithmextractbyattribute.cpp

@@ -66,7 +66,7 @@ void QgsExtractByAttributeAlgorithm::initAlgorithm( const QVariantMap & )
 
 QString QgsExtractByAttributeAlgorithm::shortHelpString() const
 {
-  return QObject::tr( "  This algorithm creates a new vector layer that only contains matching features from an input layer. "
+  return QObject::tr( "This algorithm creates a new vector layer that only contains matching features from an input layer. "
                       "The criteria for adding features to the resulting layer is defined based on the values "
                       "of an attribute from the input layer." );
 }

src/analysis/processing/qgsalgorithmfiledownloader.cpp

@@ -0,0 +1,132 @@
+/***************************************************************************
+                         qgsalgorithmfiledownloader.cpp
+                         ---------------------
+    begin                : October 2017
+    copyright            : (C) 2017 by Etienne Trimaille
+    email                : etienne at kartoza dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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 "qgsalgorithmfiledownloader.h"
+#include "qgsfiledownloader.h"
+#include <QEventLoop>
+#include <QFileInfo>
+#include <QTimer>
+#include <QUrl>
+
+///@cond PRIVATE
+
+QString QgsFileDownloaderAlgorithm::name() const
+{
+  return QStringLiteral( "filedownloader" );
+}
+
+QString QgsFileDownloaderAlgorithm::displayName() const
+{
+  return tr( "File downloader" );
+}
+
+QStringList QgsFileDownloaderAlgorithm::tags() const
+{
+  return tr( "file,downloader,internet,url" ).split( ',' );
+}
+
+QString QgsFileDownloaderAlgorithm::group() const
+{
+  return tr( "File tool" );
+}
+
+QString QgsFileDownloaderAlgorithm::shortHelpString() const
+{
+  return tr( "This algorithm downloads a URL on the file system." );
+}
+
+QgsFileDownloaderAlgorithm *QgsFileDownloaderAlgorithm::createInstance() const
+{
+  return new QgsFileDownloaderAlgorithm();
+}
+
+void QgsFileDownloaderAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterString( QStringLiteral( "URL" ), tr( "URL" ), QVariant(), false, false ) );
+  addParameter( new QgsProcessingParameterFileDestination( QStringLiteral( "OUTPUT" ),
+                tr( "File destination" ), QObject::tr( "*.*" ), QVariant(), true ) );
+  addOutput( new QgsProcessingOutputFile( QStringLiteral( "OUTPUT" ), tr( "File destination" ) ) );
+}
+
+QVariantMap QgsFileDownloaderAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
+{
+  mFeedback = feedback;
+  QString url = parameterAsString( parameters, QStringLiteral( "URL" ), context );
+  QString outputFile = parameterAsFileOutput( parameters, QStringLiteral( "OUTPUT" ), context );
+
+  QEventLoop loop;
+  QTimer timer;
+  QgsFileDownloader *downloader = new QgsFileDownloader( QUrl( url ), outputFile, QString(), true );
+  connect( mFeedback, &QgsFeedback::canceled, downloader, &QgsFileDownloader::cancelDownload );
+  connect( downloader, &QgsFileDownloader::downloadError, this, &QgsFileDownloaderAlgorithm::reportErrors );
+  connect( downloader, &QgsFileDownloader::downloadProgress, this, &QgsFileDownloaderAlgorithm::receiveProgressFromDownloader );
+  connect( downloader, &QgsFileDownloader::downloadExited, &loop, &QEventLoop::quit );
+  connect( &timer, &QTimer::timeout, this, &QgsFileDownloaderAlgorithm::sendProgressFeedback );
+  downloader->startDownload();
+  timer.start( 1000 );
+
+  loop.exec();
+
+  timer.stop();
+  if ( ! QFileInfo( outputFile ).exists() )
+    throw QgsProcessingException( tr( "Output file doesn't exist." ) );
+
+  QVariantMap outputs;
+  outputs.insert( QStringLiteral( "OUTPUT" ), outputFile );
+  return outputs;
+}
+
+void QgsFileDownloaderAlgorithm::reportErrors( QStringList errors )
+{
+  throw QgsProcessingException( errors.join( '\n' ) );
+}
+
+void QgsFileDownloaderAlgorithm::sendProgressFeedback()
+{
+  if ( ! mReceived.isEmpty() &&  ! mTotal.isEmpty() )
+    mFeedback->pushInfo( tr( "%1 of %2 downloaded." ).arg( mReceived ).arg( mTotal ) );
+}
+
+void QgsFileDownloaderAlgorithm::receiveProgressFromDownloader( qint64 bytesReceived, qint64 bytesTotal )
+{
+  if ( bytesTotal != 0 )
+  {
+    if ( mTotal.isEmpty() )
+      mTotal = humanSize( bytesTotal );
+
+    mReceived = humanSize( bytesReceived );
+    mFeedback->setProgress( ( bytesReceived * 100 ) / bytesTotal );
+  }
+}
+
+QString QgsFileDownloaderAlgorithm::humanSize( qint64 &bytes )
+{
+  QStringList list;
+  list << "KB" << "MB" << "GB" << "TB";
+
+  QStringListIterator i( list );
+  QString unit( "bytes" );
+
+  while ( bytes >= 1024.0 && i.hasNext() )
+  {
+    unit = i.next();
+    bytes /= 1024.0;
+  }
+  return QString( "%1 %2" ).arg( QString::number( bytes ) ).arg( unit );
+}
+
+///@endcond

src/analysis/processing/qgsalgorithmfiledownloader.h

@@ -0,0 +1,62 @@
+/***************************************************************************
+                         qgsalgorithmfiledownloader.h
+                         ---------------------
+    begin                : October 2017
+    copyright            : (C) 2017 by Etienne Trimaille
+    email                : etienne at kartoza dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSALGORITHMFILEDOWNLOADER_H
+#define QGSALGORITHMFILEDOWNLOADER_H
+
+#define SIP_NO_FILE
+
+#include "qgis.h"
+#include "qgsprocessingalgorithm.h"
+
+class QgsProcessingFeedback;
+
+///@cond PRIVATE
+
+/**
+ * Native file downloader algorithm.
+ */
+class QgsFileDownloaderAlgorithm : public QgsProcessingAlgorithm, public QObject
+{
+  public:
+    QgsFileDownloaderAlgorithm() = default;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QString name() const override;
+    QString displayName() const override;
+    virtual QStringList tags() const override;
+    QString group() const override;
+    QString shortHelpString() const override;
+    QgsFileDownloaderAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                          QgsProcessingContext &context, QgsProcessingFeedback * ) override;
+
+  private:
+    QString mTotal;
+    QString mReceived;
+    QgsProcessingFeedback *mFeedback = nullptr;
+    void reportErrors( QStringList errors );
+    void receiveProgressFromDownloader( qint64 bytesReceived, qint64 bytesTotal );
+    static QString humanSize( qint64 &bytes );
+    void sendProgressFeedback();
+};
+
+///@endcond PRIVATE
+
+#endif // QGSALGORITHMFILEDOWNLOADER_H

src/analysis/processing/qgsnativealgorithms.cpp

@@ -32,6 +32,7 @@
 #include "qgsalgorithmextractbyexpression.h"
 #include "qgsalgorithmextractbyextent.h"
 #include "qgsalgorithmextractbylocation.h"
+#include "qgsalgorithmfiledownloader.h"
 #include "qgsalgorithmfixgeometries.h"
 #include "qgsalgorithmjoinbyattribute.h"
 #include "qgsalgorithmjoinwithlines.h"
@@ -92,6 +93,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
   addAlgorithm( new QgsCollectAlgorithm() );
   addAlgorithm( new QgsExtractByAttributeAlgorithm() );
   addAlgorithm( new QgsExtractByExpressionAlgorithm() );
+  addAlgorithm( new QgsFileDownloaderAlgorithm() );
   addAlgorithm( new QgsMultipartToSinglepartAlgorithm() );
   addAlgorithm( new QgsSubdivideAlgorithm() );
   addAlgorithm( new QgsTransformAlgorithm() );