File downloader for identify dialog hyperlinks

fixes #14703

Include C++ and Python tests

Author: elpaso

python/gui/gui.sip

@@ -81,6 +81,7 @@
 %Include qgsfieldvalidator.sip
 %Include qgsfiledropedit.sip
 %Include qgsfilewidget.sip
+%Include qgsfiledownloader.sip
 %Include qgsfilterlineedit.sip
 %Include qgsfocuswatcher.sip
 %Include qgsformannotationitem.sip

python/gui/qgsfiledownloader.sip

@@ -0,0 +1,64 @@
+/***************************************************************************
+  qgsfiledownloader.sip
+  --------------------------------------
+  Date                 : November 2016
+  Copyright            : (C) 2016 by Alessandro Pasotti
+  Email                : elpaso at itopen dot it
+ ***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+/** \ingroup gui
+ * QgsFileDownloader is a utility class for downloading files.
+ *
+ * To use this class, it is necessary to pass the URL and an output file name as
+ * arguments to the constructor, the download will start immediately.
+ * The download is asynchronous and depending on the guiNotificationsEnabled
+ * parameter accepted by the constructor (default = true) the class will
+ * show a progress dialog and report all errors in a QMessageBox::warning dialog.
+ * If the guiNotificationsEnabled parameter is set to false, the class can still
+ * be used through the signals and slots mechanism.
+ * The object will destroy itself when the request completes, errors or is canceled.
+ */
+class QgsFileDownloader : public QObject
+{
+  %TypeHeaderCode
+  #include <qgsfiledownloader.h>
+  %End
+  public:
+    /**
+     * QgsFileDownloader
+     * @param url the download url
+     * @param outputFileName file name where the downloaded content will be stored
+     * @param guiNotificationsEnabled if false, the downloader will not display any progress bar or error message
+     */
+    QgsFileDownloader(QUrl url, QString outputFileName, bool guiNotificationsEnabled = true);
+
+    signals:
+      /** Emitted when the download has completed successfully  */
+      void downloadCompleted();
+      /** Emitted always when the downloader exits */
+      void downloadExited();
+      /** Emitted when the download was canceled by the user */
+      void downloadCanceled();
+      /** Emitted when an error makes the download fail */
+       void downloadError( QStringList errorMessages );
+      /** Emitted when data ready to be processed */
+      void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+
+    public slots:
+      /**
+       * Called when a download is canceled by the user
+       * this slot aborts the download and deletes the object
+       */
+      void onDownloadCanceled();
+
+    private:
+      ~QgsFileDownloader();
+
+};

src/app/qgsidentifyresultsdialog.cpp

@@ -38,6 +38,7 @@
 #include "qgswebview.h"
 #include "qgswebframe.h"
 #include "qgsstringutils.h"
+#include "qgsfiledownloader.h"
 
 #include <QCloseEvent>
 #include <QLabel>
@@ -55,6 +56,11 @@
 #include <QMessageBox>
 #include <QComboBox>
 #include <QTextDocument>
+#include <QNetworkRequest>
+#include <QNetworkReply>
+#include <QFileDialog>
+#include <QFileInfo>
+#include <QRegExp>
 
 //graph
 #include <qwt_plot.h>
@@ -68,13 +74,63 @@ QgsIdentifyResultsWebView::QgsIdentifyResultsWebView( QWidget *parent ) : QgsWeb
   setSizePolicy( QSizePolicy::MinimumExpanding, QSizePolicy::Minimum );
   page()->setNetworkAccessManager( QgsNetworkAccessManager::instance() );
   // page()->setLinkDelegationPolicy( QWebPage::DelegateAllLinks );
+  page()->setForwardUnsupportedContent( true );
   page()->setLinkDelegationPolicy( QWebPage::DontDelegateLinks );
   settings()->setAttribute( QWebSettings::LocalContentCanAccessRemoteUrls, true );
   settings()->setAttribute( QWebSettings::JavascriptCanOpenWindows, true );
   settings()->setAttribute( QWebSettings::PluginsEnabled, true );
 #ifdef QGISDEBUG
   settings()->setAttribute( QWebSettings::DeveloperExtrasEnabled, true );
 #endif
+  connect( page(), SIGNAL( downloadRequested( QNetworkRequest ) ), this, SLOT( downloadRequested( QNetworkRequest ) ) );
+  connect( page(), SIGNAL( unsupportedContent( QNetworkReply* ) ), this, SLOT( unsupportedContent( QNetworkReply* ) ) );
+}
+
+
+void QgsIdentifyResultsWebView::downloadRequested( const QNetworkRequest &request )
+{
+  qDebug() << "Download Requested: " << request.url();
+  handleDownload( request.url() );
+}
+
+void QgsIdentifyResultsWebView::unsupportedContent( QNetworkReply * reply )
+{
+  qDebug() << "Unsupported Content: " << reply->url();
+  handleDownload( reply->url() );
+}
+
+void QgsIdentifyResultsWebView::handleDownload( QUrl url )
+{
+  qDebug() << "Downloading: " << url;
+  if ( ! url.isValid() )
+  {
+    QMessageBox::warning( this, tr( "Invalid URL" ), tr( "The download URL is not valid: %1" ).arg( url.toString( ) ) );
+  }
+  else
+  {
+    const QString DOWNLOADER_LAST_DIR_KEY( "Qgis/fileDownloaderLastDir" );
+    QSettings settings;
+    // Try to get some information from the URL
+    QFileInfo info( url.toString( ) );
+    QString savePath = settings.value( DOWNLOADER_LAST_DIR_KEY ).toString( );
+    QString fileName = info.fileName().replace( QRegExp( "[^A-z0-9\\-_\\.]" ), "_" );
+    if ( ! savePath.isEmpty() && ! fileName.isEmpty( ) )
+    {
+      savePath = QDir::cleanPath( savePath + QDir::separator() + fileName );
+    }
+    QString targetFile = QFileDialog::getSaveFileName( this,
+                         tr( "Save as" ),
+                         savePath,
+                         info.suffix( ).isEmpty() ? QString( ) : "*." +  info.suffix( )
+                                                     );
+    if ( ! targetFile.isEmpty() )
+    {
+      settings.setValue( DOWNLOADER_LAST_DIR_KEY, QFileInfo( targetFile ).dir().absolutePath( ) );
+      // Start the download
+      qDebug() << "Start the download: " << url;
+      new QgsFileDownloader( url, targetFile );
+    }
+  }
 }
 
 void QgsIdentifyResultsWebView::print()

src/app/qgsidentifyresultsdialog.h

@@ -31,6 +31,9 @@
 
 #include <QWidget>
 #include <QList>
+#include <QNetworkRequest>
+#include <QNetworkReply>
+#include <QUrl>
 
 class QCloseEvent;
 class QTreeWidgetItem;
@@ -57,9 +60,13 @@ class APP_EXPORT QgsIdentifyResultsWebView : public QgsWebView
     QSize sizeHint() const override;
   public slots:
     void print();
+    void downloadRequested( const QNetworkRequest &request );
+    void unsupportedContent( QNetworkReply *reply );
   protected:
     void contextMenuEvent( QContextMenuEvent* ) override;
     QgsWebView *createWindow( QWebPage::WebWindowType type ) override;
+  private:
+    void handleDownload( QUrl url );
 };
 
 class APP_EXPORT QgsIdentifyResultsFeatureItem: public QTreeWidgetItem

src/gui/CMakeLists.txt

@@ -307,6 +307,7 @@ SET(QGIS_GUI_SRCS
   qgsuserinputdockwidget.cpp
   qgsvariableeditorwidget.cpp
   qgsvertexmarker.cpp
+  qgsfiledownloader.cpp
 )
 
 IF (WITH_QTWEBKIT)
@@ -454,6 +455,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsunitselectionwidget.h
   qgsuserinputdockwidget.h
   qgsvariableeditorwidget.h
+  qgsfiledownloader.h
 
   raster/qgsmultibandcolorrendererwidget.h
   raster/qgspalettedrendererwidget.h
@@ -648,6 +650,7 @@ SET(QGIS_GUI_HDRS
   qgsuserinputdockwidget.h
   qgsvectorlayertools.h
   qgsvertexmarker.h
+  qgsfiledownloader.h
 
   attributetable/qgsfeaturemodel.h