Add a QgsTask for fetching network content

Provides a simple method for fetching remote HTTP content in a QgsTask. Utilises QgsNetworkContentFetcher so Url redirects and progress reports are automatically handled. (cherry-picked from e2f09fa)
qgis · Apr 6, 2018 · d39d268 · d39d268
1 parent 61a650a
commit d39d268
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Showing 10 changed files with 354 additions and 8 deletions.
diff --git a/python/core/core_auto.sip b/python/core/core_auto.sip
@@ -329,6 +329,7 @@
 %Include qgsmessageoutput.sip
 %Include qgsnetworkaccessmanager.sip
 %Include qgsnetworkcontentfetcher.sip
+%Include qgsnetworkcontentfetchertask.sip
 %Include qgsofflineediting.sip
 %Include qgspluginlayer.sip
 %Include qgspointxy.sip

diff --git a/python/core/qgsnetworkcontentfetcher.sip.in b/python/core/qgsnetworkcontentfetcher.sip.in
@@ -11,7 +11,6 @@
 
 
 
-
 class QgsNetworkContentFetcher : QObject
 {
 %Docstring
@@ -20,6 +19,8 @@ and converting the content to standard formats. Url redirects are automatically
 handled.
 
 .. versionadded:: 2.5
+
+.. seealso:: :py:class:`QgsNetworkContentFetcherTask`
 %End
 
 %TypeHeaderCode
@@ -69,6 +70,13 @@ Returns the fetched content as a string
     void finished();
 %Docstring
 Emitted when content has loaded
+%End
+
+    void downloadProgress( qint64 bytesReceived, qint64 bytesTotal );
+%Docstring
+Emitted when data is received.
+
+.. versionadded:: 3.2
 %End
 
 };

diff --git a/python/core/qgsnetworkcontentfetchertask.sip.in b/python/core/qgsnetworkcontentfetchertask.sip.in
@@ -0,0 +1,81 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsnetworkcontentfetchertask.h                              *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+
+class QgsNetworkContentFetcherTask : QgsTask
+{
+%Docstring
+ Handles HTTP network content fetching in a background task.
+
+Provides a simple method for fetching remote HTTP content in a QgsTask.
+Url redirects are automatically handled.
+
+After constructing a QgsNetworkContentFetcherTask, callers should
+connect to the QgsNetworkContentFetcherTask.fetched signal. They can
+then safely access the network reply() from the connected slot
+without danger of the task being first removed by the QgsTaskManager.
+
+.. seealso:: :py:class:`QgsNetworkContentFetcher`
+
+.. versionadded:: 3.2
+%End
+
+%TypeHeaderCode
+#include "qgsnetworkcontentfetchertask.h"
+%End
+  public:
+
+    QgsNetworkContentFetcherTask( const QUrl &url );
+%Docstring
+Constructor for a QgsNetworkContentFetcherTask which fetches
+the specified ``url``.
+%End
+
+    QgsNetworkContentFetcherTask( const QNetworkRequest &request );
+%Docstring
+Constructor for a QgsNetworkContentFetcherTask which fetches
+the specified network ``request``.
+%End
+
+    ~QgsNetworkContentFetcherTask();
+
+    virtual bool run();
+
+
+    QNetworkReply *reply();
+%Docstring
+Returns the network reply. Ownership is not transferred.
+
+May return None if the request has not yet completed.
+%End
+
+  signals:
+
+    void fetched();
+%Docstring
+Emitted when the network content has been fetched, regardless
+of whether the fetch was successful or not.
+
+Users of QgsNetworkContentFetcherTask should connect to this signal,
+and from the associated slot they can then safely access the network reply()
+without danger of the task being first removed by the :py:class:`QgsTaskManager`.
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsnetworkcontentfetchertask.h                              *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -235,6 +235,7 @@ SET(QGIS_CORE_SRCS
   qgsnetworkaccessmanager.cpp
   qgsnetworkdiskcache.cpp
   qgsnetworkcontentfetcher.cpp
+  qgsnetworkcontentfetchertask.cpp
   qgsnetworkreplyparser.cpp
   qgsobjectcustomproperties.cpp
   qgsofflineediting.cpp
@@ -610,6 +611,7 @@ SET(QGIS_CORE_MOC_HDRS
   qgsnetworkaccessmanager.h
   qgsnetworkdiskcache.h
   qgsnetworkcontentfetcher.h
+  qgsnetworkcontentfetchertask.h
   qgsnetworkreplyparser.h
   qgsofflineediting.h
   qgsowsconnection.h

diff --git a/src/core/qgsnetworkcontentfetcher.cpp b/src/core/qgsnetworkcontentfetcher.cpp
@@ -55,6 +55,7 @@ void QgsNetworkContentFetcher::fetchContent( const QNetworkRequest &request )
 
   mReply = QgsNetworkAccessManager::instance()->get( request );
   connect( mReply, &QNetworkReply::finished, this, [ = ] { contentLoaded(); } );
+  connect( mReply, &QNetworkReply::downloadProgress, this, &QgsNetworkContentFetcher::downloadProgress );
 }
 
 QNetworkReply *QgsNetworkContentFetcher::reply()

diff --git a/src/core/qgsnetworkcontentfetcher.h b/src/core/qgsnetworkcontentfetcher.h
@@ -26,14 +26,14 @@
 #include "qgis_core.h"
 
 /**
-  \class QgsNetworkContentFetcher
-  \ingroup core
-  \brief HTTP network content fetcher. A simple method for fetching remote HTTP content
-  and converting the content to standard formats. Url redirects are automatically
-  handled.
-  \since 2.5
+ * \class QgsNetworkContentFetcher
+ * \ingroup core
+ * \brief HTTP network content fetcher. A simple method for fetching remote HTTP content
+ * and converting the content to standard formats. Url redirects are automatically
+ * handled.
+ * \since QGIS 2.5
+ * \see QgsNetworkContentFetcherTask
 */
-
 class CORE_EXPORT QgsNetworkContentFetcher : public QObject
 {
     Q_OBJECT
@@ -81,6 +81,12 @@ class CORE_EXPORT QgsNetworkContentFetcher : public QObject
      */
     void finished();
 
+    /**
+     * Emitted when data is received.
+     * \since QGIS 3.2
+     */
+    void downloadProgress( qint64 bytesReceived, qint64 bytesTotal );
+
   private:
 
     QNetworkReply *mReply = nullptr;

diff --git a/src/core/qgsnetworkcontentfetchertask.cpp b/src/core/qgsnetworkcontentfetchertask.cpp
@@ -0,0 +1,60 @@
+/***************************************************************************
+                       qgsnetworkcontentfetchertask.cpp
+                             -------------------
+    begin                : March 2018
+    copyright            : (C) 2018 by Nyall Dawson
+    email                : nyall dot dawson at gmail 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 "qgsnetworkcontentfetchertask.h"
+#include "qgsnetworkcontentfetcher.h"
+
+QgsNetworkContentFetcherTask::QgsNetworkContentFetcherTask( const QUrl &url )
+  : QgsNetworkContentFetcherTask( QNetworkRequest( url ) )
+{
+}
+
+QgsNetworkContentFetcherTask::QgsNetworkContentFetcherTask( const QNetworkRequest &request )
+  : QgsTask( tr( "Fetching %1" ).arg( request.url().toString() ) )
+  , mRequest( request )
+{
+}
+
+QgsNetworkContentFetcherTask::~QgsNetworkContentFetcherTask()
+{
+  if ( mFetcher )
+    mFetcher->deleteLater();
+}
+
+bool QgsNetworkContentFetcherTask::run()
+{
+  mFetcher = new QgsNetworkContentFetcher();
+  QEventLoop loop;
+  connect( mFetcher, &QgsNetworkContentFetcher::finished, &loop, &QEventLoop::quit );
+  connect( mFetcher, &QgsNetworkContentFetcher::downloadProgress, this, [ = ]( qint64 bytesReceived, qint64 bytesTotal )
+  {
+    if ( bytesTotal > 0 )
+    {
+      setProgress( ( bytesReceived * 100 ) / bytesTotal );
+    }
+  } );
+  mFetcher->fetchContent( mRequest );
+  loop.exec();
+  emit fetched();
+  return true;
+}
+
+QNetworkReply *QgsNetworkContentFetcherTask::reply()
+{
+  return mFetcher ? mFetcher->reply() : nullptr;
+}
diff --git a/src/core/qgsnetworkcontentfetchertask.h b/src/core/qgsnetworkcontentfetchertask.h
@@ -0,0 +1,95 @@
+/***************************************************************************
+                       qgsnetworkcontentfetchertask.h
+                             -------------------
+    begin                : March, 2018
+    copyright            : (C) 2018 by Nyall Dawson
+    email                : nyall dot dawson at gmail 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 QGSNETWORKCONTENTFETCHERTASK_H
+#define QGSNETWORKCONTENTFETCHERTASK_H
+
+#include "qgstaskmanager.h"
+#include "qgis_core.h"
+#include <QNetworkRequest>
+
+class QgsNetworkContentFetcher;
+class QNetworkReply;
+
+/**
+ * \class QgsNetworkContentFetcherTask
+ * \ingroup core
+ * \brief Handles HTTP network content fetching in a background task.
+ *
+ * Provides a simple method for fetching remote HTTP content in a QgsTask.
+ * Url redirects are automatically handled.
+ *
+ * After constructing a QgsNetworkContentFetcherTask, callers should
+ * connect to the QgsNetworkContentFetcherTask::fetched signal. They can
+ * then safely access the network reply() from the connected slot
+ * without danger of the task being first removed by the QgsTaskManager.
+ *
+ * \see QgsNetworkContentFetcher
+ *
+ * \since QGIS 3.2
+*/
+class CORE_EXPORT QgsNetworkContentFetcherTask : public QgsTask
+{
+    Q_OBJECT
+
+  public:
+
+    /**
+     * Constructor for a QgsNetworkContentFetcherTask which fetches
+     * the specified \a url.
+     */
+    QgsNetworkContentFetcherTask( const QUrl &url );
+
+    /**
+     * Constructor for a QgsNetworkContentFetcherTask which fetches
+     * the specified network \a request.
+     */
+    QgsNetworkContentFetcherTask( const QNetworkRequest &request );
+
+    ~QgsNetworkContentFetcherTask();
+
+    bool run() override;
+
+    /**
+     * Returns the network reply. Ownership is not transferred.
+     *
+     * May return nullptr if the request has not yet completed.
+     */
+    QNetworkReply *reply();
+
+  signals:
+
+    /**
+     * Emitted when the network content has been fetched, regardless
+     * of whether the fetch was successful or not.
+     *
+     * Users of QgsNetworkContentFetcherTask should connect to this signal,
+     * and from the associated slot they can then safely access the network reply()
+     * without danger of the task being first removed by the QgsTaskManager.
+     */
+    void fetched();
+
+  private:
+
+    QNetworkRequest mRequest;
+    QgsNetworkContentFetcher *mFetcher = nullptr;
+
+};
+
+#endif //QGSNETWORKCONTENTFETCHERTASK_H
diff --git a/tests/src/python/CMakeLists.txt b/tests/src/python/CMakeLists.txt
@@ -112,6 +112,7 @@ ADD_PYTHON_TEST(PyQgsMargins test_qgsmargins.py)
 ADD_PYTHON_TEST(PyQgsMemoryProvider test_provider_memory.py)
 ADD_PYTHON_TEST(PyQgsMultiEditToolButton test_qgsmultiedittoolbutton.py)
 ADD_PYTHON_TEST(PyQgsNetworkContentFetcher test_qgsnetworkcontentfetcher.py)
+ADD_PYTHON_TEST(PyQgsNetworkContentFetcherTask test_qgsnetworkcontentfetchertask.py)
 ADD_PYTHON_TEST(PyQgsNullSymbolRenderer test_qgsnullsymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsNewGeoPackageLayerDialog test_qgsnewgeopackagelayerdialog.py)
 ADD_PYTHON_TEST(PyQgsNoApplication test_qgsnoapplication.py)