First steps to model/save restore in c++

Models now save to QVariantMap, using QgsXmlUtils to save to
an xml based format (with extension .model3)

Author: nyalldawson

python/core/processing/qgsprocessingmodelalgorithm.sip

@@ -139,6 +139,20 @@ class QgsProcessingModelAlgorithm : QgsProcessingAlgorithm
 .. seealso:: setOutputChildId()
 %End
 
+        QVariant toVariant() const;
+%Docstring
+ Saves this source to a QVariant.
+.. seealso:: loadVariant()
+ :rtype: QVariant
+%End
+
+        bool loadVariant( const QVariantMap &map );
+%Docstring
+ Loads this source from a QVariantMap.
+.. seealso:: toVariant()
+ :rtype: bool
+%End
+
     };
 
     class Component
@@ -192,6 +206,18 @@ Copies are protected to avoid slicing
 %End
 
 
+        void saveCommonProperties( QVariantMap &map ) const;
+%Docstring
+ Saves the component properties to a QVariantMap.
+.. seealso:: restoreCommonProperties()
+%End
+
+        void restoreCommonProperties( const QVariantMap &map );
+%Docstring
+ Restores the component properties from a QVariantMap.
+.. seealso:: saveCommonProperties()
+%End
+
     };
 
     class ModelParameter : QgsProcessingModelAlgorithm::Component
@@ -227,6 +253,20 @@ Copies are protected to avoid slicing
 .. seealso:: parameterName()
 %End
 
+        QVariant toVariant() const;
+%Docstring
+ Saves this parameter to a QVariant.
+.. seealso:: loadVariant()
+ :rtype: QVariant
+%End
+
+        bool loadVariant( const QVariantMap &map );
+%Docstring
+ Loads this parameter from a QVariantMap.
+.. seealso:: toVariant()
+ :rtype: bool
+%End
+
     };
 
 
@@ -273,6 +313,20 @@ Copies are protected to avoid slicing
 .. seealso:: outputName()
 %End
 
+        QVariant toVariant() const;
+%Docstring
+ Saves this output to a QVariant.
+.. seealso:: loadVariant()
+ :rtype: QVariant
+%End
+
+        bool loadVariant( const QVariantMap &map );
+%Docstring
+ Loads this output from a QVariantMap.
+.. seealso:: toVariant()
+ :rtype: bool
+%End
+
     };
 
     class ChildAlgorithm : QgsProcessingModelAlgorithm::Component
@@ -461,6 +515,20 @@ Copies are protected to avoid slicing
 .. seealso:: modelOutputs()
 %End
 
+        QVariant toVariant() const;
+%Docstring
+ Saves this child to a QVariant.
+.. seealso:: loadVariant()
+ :rtype: QVariant
+%End
+
+        bool loadVariant( const QVariant &child );
+%Docstring
+ Loads this child from a QVariant.
+.. seealso:: toVariant()
+ :rtype: bool
+%End
+
     };
 
     QgsProcessingModelAlgorithm( const QString &name = QString(), const QString &group = QString() );
@@ -484,6 +552,18 @@ Copies are protected to avoid slicing
      virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
                                   QgsProcessingContext &context, QgsProcessingFeedback *feedback ) const;
 
+    void setName( const QString &name );
+%Docstring
+ Sets the model ``name``.
+.. seealso:: name()
+%End
+
+    void setGroup( const QString &group );
+%Docstring
+ Sets the model ``group``.
+.. seealso:: group()
+%End
+
     QMap<QString, QgsProcessingModelAlgorithm::ChildAlgorithm> childAlgorithms() const;
 %Docstring
  Returns the map of child algorithms contained in the model. The keys
@@ -651,6 +731,20 @@ Copies are protected to avoid slicing
  :rtype: QgsProcessingModelAlgorithm.ModelParameter
 %End
 
+    bool toFile( const QString &path ) const;
+%Docstring
+ Writes the model to a file, at the specified ``path``.
+.. seealso:: fromFile()
+ :rtype: bool
+%End
+
+    bool fromFile( const QString &path );
+%Docstring
+ Reads the model from a file, at the specified ``path``.
+.. seealso:: toFile()
+ :rtype: bool
+%End
+
 };
 
 

python/plugins/processing/modeler/AddModelFromFileAction.py

@@ -56,22 +56,16 @@ def execute(self):
                                                                 self.tr('Open model', 'AddModelFromFileAction'), lastDir,
                                                                 self.tr('Processing model files (*.model *.MODEL)', 'AddModelFromFileAction'))
         if filename:
-            try:
-                settings.setValue('Processing/lastModelsDir',
-                                  QFileInfo(filename).absoluteDir().absolutePath())
+            settings.setValue('Processing/lastModelsDir',
+                              QFileInfo(filename).absoluteDir().absolutePath())
 
-                ModelerAlgorithm.fromFile(filename)
-            except WrongModelException:
+            alg = ModelerAlgorithm()
+            if not alg.fromFile(filename):
                 QMessageBox.warning(
                     self.toolbox,
                     self.tr('Error reading model', 'AddModelFromFileAction'),
                     self.tr('The selected file does not contain a valid model', 'AddModelFromFileAction'))
                 return
-            except:
-                QMessageBox.warning(self.toolbox,
-                                    self.tr('Error reading model', 'AddModelFromFileAction'),
-                                    self.tr('Cannot read file', 'AddModelFromFileAction'))
-                return
             destFilename = os.path.join(ModelerUtils.modelsFolders()[0], os.path.basename(filename))
             shutil.copyfile(filename, destFilename)
             QgsApplication.processingRegistry().providerById('model').refreshAlgorithms()

python/plugins/processing/modeler/ModelerAlgorithm.py

@@ -365,15 +365,6 @@ def _import(name):
             model._name = model.modeler_name
         return model
 
-    @staticmethod
-    def fromFile(filename):
-        with open(filename) as f:
-            s = f.read()
-        alg = ModelerAlgorithm.fromJson(s)
-        if alg:
-            alg.descriptionFile = filename
-        return alg
-
     def toPython(self):
         s = ['##%s=name' % self.name()]
         for param in list(self.parameterComponents().values()):

python/plugins/processing/modeler/ModelerAlgorithmProvider.py

@@ -27,10 +27,13 @@
 
 import os
 
+from qgis.PyQt.QtXml import QDomDocument
+
 from qgis.core import (QgsApplication,
                        QgsProcessingProvider,
                        QgsMessageLog,
-                       QgsProcessingUtils)
+                       QgsProcessingUtils,
+                       QgsXmlUtils)
 
 from processing.core.ProcessingConfig import ProcessingConfig, Setting
 from processing.modeler.ModelerUtils import ModelerUtils
@@ -98,13 +101,15 @@ def loadFromFolder(self, folder):
             return
         for path, subdirs, files in os.walk(folder):
             for descriptionFile in files:
-                if descriptionFile.endswith('model'):
+                if descriptionFile.endswith('model3'):
                     try:
                         fullpath = os.path.join(path, descriptionFile)
-                        alg = ModelerAlgorithm.fromFile(fullpath)
-                        if alg.name():
-                            alg.descriptionFile = fullpath
-                            self.algs.append(alg)
+
+                        alg = ModelerAlgorithm()
+                        if alg.fromFile(fullpath):
+                            if alg.name():
+                                alg.descriptionFile = fullpath
+                                self.algs.append(alg)
                         else:
                             QgsMessageLog.logMessage(self.tr('Could not load model {0}', 'ModelerAlgorithmProvider').format(descriptionFile),
                                                      self.tr('Processing'), QgsMessageLog.CRITICAL)

python/plugins/processing/modeler/ModelerDialog.py

@@ -42,7 +42,8 @@
                        QgsSettings,
                        QgsMessageLog,
                        QgsProcessingUtils,
-                       QgsProcessingModelAlgorithm)
+                       QgsProcessingModelAlgorithm,
+                       QgsXmlUtils)
 from qgis.gui import QgsMessageBar
 from processing.gui.HelpEditionDialog import HelpEditionDialog
 from processing.gui.AlgorithmDialog import AlgorithmDialog
@@ -52,6 +53,7 @@
 from processing.modeler.ModelerUtils import ModelerUtils
 from processing.modeler.ModelerScene import ModelerScene
 from processing.modeler.WrongModelException import WrongModelException
+from qgis.PyQt.QtXml import QDomDocument
 
 pluginPath = os.path.split(os.path.dirname(__file__))[0]
 WIDGET, BASE = uic.loadUiType(
@@ -435,25 +437,21 @@ def saveModel(self, saveAs):
                 self, self.tr('Warning'), self.tr('Please enter group and model names before saving')
             )
             return
-        self.model._name = str(self.textName.text())
-        self.model._group = str(self.textGroup.text())
+        self.model.setName(str(self.textName.text()))
+        self.model.setGroup(str(self.textGroup.text()))
         if self.model.descriptionFile is not None and not saveAs:
             filename = self.model.descriptionFile
         else:
             filename, filter = QFileDialog.getSaveFileName(self,
                                                            self.tr('Save Model'),
                                                            ModelerUtils.modelsFolders()[0],
-                                                           self.tr('Processing models (*.model)'))
+                                                           self.tr('Processing models (*.model3)'))
             if filename:
-                if not filename.endswith('.model'):
-                    filename += '.model'
+                if not filename.endswith('.model3'):
+                    filename += '.model3'
                 self.model.descriptionFile = filename
         if filename:
-            text = self.model.toJson()
-            try:
-                with codecs.open(filename, 'w', encoding='utf-8') as fout:
-                    fout.write(text)
-            except:
+            if not self.model.toFile(filename):
                 if saveAs:
                     QMessageBox.warning(self, self.tr('I/O error'),
                                         self.tr('Unable to save edits. Reason:\n {0}').format(str(sys.exc_info()[1])))
@@ -475,28 +473,22 @@ def openModel(self):
                                                                 ModelerUtils.modelsFolders()[0],
                                                                 self.tr('Processing models (*.model *.MODEL)'))
         if filename:
-            try:
-                alg = ModelerAlgorithm.fromFile(filename)
+            alg = ModelerAlgorithm()
+            if alg.fromFile(filename):
                 self.model = alg
-                self.textGroup.setText(alg._group)
-                self.textName.setText(alg._name)
+                self.textGroup.setText(alg.group())
+                self.textName.setText(alg.name())
                 self.repaintModel()
 
                 self.view.centerOn(0, 0)
                 self.hasChanged = False
-            except WrongModelException as e:
-                QgsMessageLog.logMessage(self.tr('Could not load model {0}\n{1}').format(filename, e.msg),
+            else:
+                QgsMessageLog.logMessage(self.tr('Could not load model {0}').format(filename),
                                          self.tr('Processing'),
                                          QgsMessageLog.CRITICAL)
                 QMessageBox.critical(self, self.tr('Could not open model'),
                                      self.tr('The selected model could not be loaded.\n'
                                              'See the log for more information.'))
-            except Exception as e:
-                QgsMessageLog.logMessage(self.tr('Could not load model {0}\n{1}').format(filename, e.args[0]),
-                                         self.tr('Processing'), QgsMessageLog.CRITICAL)
-                QMessageBox.critical(self, self.tr('Could not open model'),
-                                     self.tr('The selected model could not be loaded.\n'
-                                             'See the log for more information.'))
 
     def repaintModel(self, controls=True):
         self.scene = ModelerScene(self, dialog=self)