ENH: Re-factor WebChannelTransport initialization

Since only one web channel can be installed per page, this commit introduces
initializeWebChannelTransport() function allowing both base and derived class
to customize the WebChannelTransport initialization callback code.

Instead of systematically re-installing a QWebChannel, this commit
also ensure that the object `window.slicerPython` is set.

List of DataStore changes:

$ git shortlog e6278c076..8053b0283 --no-merges
Jean-Christophe Fillion-Robin (1):
      ENH: Refactor WebChannelTransport initialization

git-svn-id: http://svn.slicer.org/Slicer4/trunk@27941 3bd1e089-480b-0410-8dfb-8563597acbee

Author: jcfr

Applications/SlicerApp/Testing/Python/WebEngine.py

@@ -152,16 +152,18 @@ def test_WebEngine1(self):
     webWidget.show()
     self.delayDisplay('Showing widget')
 
-    webWidget.connect("evalResult(QString,QString)", self.onEvalResult)
-
     webWidget.evalJS("""
         const paragraph = document.createElement('p');
         paragraph.innerText = 'Hello from Slicer!';
         document.body.appendChild(paragraph);
     """)
-
     self.delayDisplay('Slicer should be saying hello!')
 
+    #
+    # Test javascript evaluation + use of "evalResult()" signal
+    #
+    webWidget.connect("evalResult(QString,QString)", self.onEvalResult)
+
     self.delayDisplay('Slicer setting a javascript value')
 
     webWidget.evalJS("const valueFromSlicer = 42;")
@@ -189,16 +191,12 @@ def test_WebEngine1(self):
     slicer.app.settings().setValue("WebEngine/AllowPythonExecution", ctk.ctkMessageBox.AcceptRole)
 
     webWidget.evalJS(r"""
-        new QWebChannel(qt.webChannelTransport, channel => {
-            const slicerPython = channel.objects.slicerPython;
-
-            let pythonCode = "dialog = qt.QInputDialog(slicer.util.mainWindow())\n";
-            pythonCode += "dialog.setLabelText('hello')\n";
-            pythonCode += "dialog.open()\n";
-            pythonCode += "qt.QTimer.singleShot(1000, dialog.close)\n";
+        let pythonCode = "dialog = qt.QInputDialog(slicer.util.mainWindow())\n";
+        pythonCode += "dialog.setLabelText('hello')\n";
+        pythonCode += "dialog.open()\n";
+        pythonCode += "qt.QTimer.singleShot(1000, dialog.close)\n";
 
-            slicerPython.evalPython(pythonCode);
-        });
+        window.slicerPython.evalPython(pythonCode);
     """)
 
     self.delayDisplay('Test access to python via js', msec=500)
@@ -207,9 +205,7 @@ def test_WebEngine1(self):
       del slicer.modules.slicerPythonValueFromJS
 
     webWidget.evalJS("""
-        new QWebChannel(qt.webChannelTransport, channel => {
-            out = channel.objects.slicerPython.evalPython("slicer.modules.slicerPythonValueFromJS = 42");
-        });
+        window.slicerPython.evalPython("slicer.modules.slicerPythonValueFromJS = 42");
     """)
 
     iteration = 0

Base/QTGUI/qSlicerExtensionsInstallWidget.cxx

@@ -152,18 +152,16 @@ void qSlicerExtensionsInstallWidgetPrivate::setFailurePage(const QStringList& er
 }
 
 // --------------------------------------------------------------------------
-void qSlicerExtensionsInstallWidgetPrivate::updateWebChannelScript(QByteArray& webChannelScript)
+void qSlicerExtensionsInstallWidgetPrivate::initializeWebChannelTransport(QByteArray& webChannelScript)
 {
 #if (QT_VERSION < QT_VERSION_CHECK(5, 6, 0))
   Q_UNUSED(webChannelScript);
 #else
+  this->Superclass::initializeWebChannelTransport(webChannelScript);
   webChannelScript.append(
-      "\n"
-      "new QWebChannel(qt.webChannelTransport, function(channel) {"
-      " window.extensions_manager_model = channel.objects.extensions_manager_model;"
+      " window.extensions_manager_model = channel.objects.extensions_manager_model;\n"
       // See ExtensionInstallWidgetWebChannelProxy
-      " window.extensions_install_widget = channel.objects.extensions_install_widget;"
-      "});"
+      " window.extensions_install_widget = channel.objects.extensions_install_widget;\n"
       );
 #endif
 }

Base/QTGUI/qSlicerExtensionsInstallWidget_p.h

@@ -66,8 +66,8 @@ class qSlicerExtensionsInstallWidgetPrivate : public qSlicerWebWidgetPrivate
 
   void setFailurePage(const QStringList &errors);
 
-  virtual void updateWebChannelScript(QByteArray& webChannelScript);
   virtual void initializeWebChannel(QWebChannel* webChannel);
+  virtual void initializeWebChannelTransport(QByteArray& webChannelScript);
   void registerExtensionsManagerModel(qSlicerExtensionsManagerModel* oldModel, qSlicerExtensionsManagerModel* newModel);
 
   qSlicerExtensionsManagerModel * ExtensionsManagerModel;

Base/QTGUI/qSlicerWebWidget.cxx

@@ -212,6 +212,29 @@ void qSlicerWebWidgetPrivate::onAppAboutToQuit()
 #endif
 }
 
+// --------------------------------------------------------------------------
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+void qSlicerWebWidgetPrivate::updateWebChannelScript(QByteArray& webChannelScript)
+{
+  webChannelScript.append(
+        "\n"
+        "new QWebChannel(qt.webChannelTransport, function(channel) {\n"
+        );
+  this->initializeWebChannelTransport(webChannelScript);
+  webChannelScript.append(
+        "});\n"
+        );
+}
+#endif
+
+// --------------------------------------------------------------------------
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+void qSlicerWebWidgetPrivate::initializeWebChannelTransport(QByteArray& webChannelScript)
+{
+  webChannelScript.append(" window.slicerPython = channel.objects.slicerPython;\n");
+}
+#endif
+
 // --------------------------------------------------------------------------
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
 void qSlicerWebWidgetPrivate::initializeWebEngineProfile(QWebEngineProfile* profile)

Base/QTGUI/qSlicerWebWidget_p.h

@@ -114,8 +114,21 @@ class Q_SLICER_BASE_QTGUI_EXPORT qSlicerWebWidgetPrivate: public QObject, Ui_qSl
   /// script content.
   virtual void initializeWebEngineProfile(QWebEngineProfile* profile);
 
+  /// \brief Append additional script content to ``qwebchannel_appended.js``.
+  ///
+  /// The default implementation instantiates a ``QWebChannel`` JS object and
+  /// call initializeWebChannelTransport() to provide derived classes with an
+  /// opportunity to further customize the WebChannelTransport initialization
+  /// callback code.
+  ///
   /// \sa initializeWebEngineProfile(QWebEngineProfile*)
-  virtual void updateWebChannelScript(QByteArray& /* webChannelScript */){}
+  virtual void updateWebChannelScript(QByteArray& /* webChannelScript */);
+
+  /// \brief Append additional script content to the WebChannelTransport initialization
+  /// callback associated with the default QWebChannel.
+  ///
+  /// \sa updateWebChannelScript()
+  virtual void initializeWebChannelTransport(QByteArray& /* webChannelScript */);
 
   virtual void initializeWebChannel(QWebChannel* /* webChannel */);
 

SuperBuild.cmake

@@ -301,7 +301,7 @@ list_conditional_append(Slicer_BUILD_OtsuThresholdImageFilter Slicer_REMOTE_DEPE
 
 Slicer_Remote_Add(DataStore
   GIT_REPOSITORY "${EP_GIT_PROTOCOL}://github.com/Slicer/Slicer-DataStore"
-  GIT_TAG "e6278c07610d0a8719bfa65b24f2aa7c28332d68"
+  GIT_TAG "8053b0283583d93b223c43bbf4678cb9adf7b0c7"
   OPTION_NAME Slicer_BUILD_DataStore
   LABELS REMOTE_MODULE
   )