def chooseOutputFile(self):
        # get last used dir
        settings = QgsSettings()
        lastUsedDir = settings.value(self.lastUsedVectorDirSettingsKey, ".")

        # get selected filter
        selectedFilter = self.cboFileFormat.currentData()

        # ask for a filename
        filename, filter = QFileDialog.getSaveFileName(self, self.tr("Choose where to save the file"), lastUsedDir,
                                                       selectedFilter)
        if filename == "":
            return

        filterString = QgsVectorFileWriter.filterForDriver(selectedFilter)
        ext = filterString[filterString.find('.'):]
        ext = ext[:ext.find(' ')]

        if not filename.lower().endswith(ext):
            filename += ext

        # store the last used dir
        settings.setValue(self.lastUsedVectorDirSettingsKey, QFileInfo(filename).filePath())

        self.editOutputFile.setText(filename)

def main():
    datestamp = datetime.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
    if QT5:
        ini_out_dir = QStandardPaths.writableLocation(QStandardPaths.DesktopLocation)
    else:
        ini_out_dir = QDesktopServices.storageLocation(QDesktopServices.DesktopLocation)
    ini_name = 'org.qgis.{0}-settings_{1}.ini'.format(QGIS_APP_NAME, datestamp)
    ini_out = QDir(ini_out_dir).absoluteFilePath(ini_name)

    if not os.path.exists(ini_out_dir):
        print('INI output directory does not exist: {0}'.format(ini_out_dir))
        return

    if not os.access(ini_out_dir, os.W_OK | os.X_OK):
        print('INI output directory is not writeable: {0}'.format(ini_out_dir))
        return

    # QGIS settings
    if HAS_QGSSETTINGS:
        qgis_settings = QgsSettings()
    else:
        qgis_settings = QSettings()

    # Output INI settings
    ini_settings = QSettings(ini_out, QSettings.IniFormat)

    qgis_keys = qgis_settings.allKeys()
    for k in qgis_keys:
        ini_settings.setValue(k, qgis_settings.value(k))

    ini_settings.sync()

    print("Settings output to: {0}".format(QDir.toNativeSeparators(ini_out)))

    def saveToPostGIS(self):
        dlg = PostgisTableSelector(self, self.parameter.name().lower())
        dlg.exec_()
        if dlg.connection:
            self.use_temporary = False
            settings = QgsSettings()
            mySettings = '/PostgreSQL/connections/' + dlg.connection
            dbname = settings.value(mySettings + '/database')
            user = settings.value(mySettings + '/username')
            host = settings.value(mySettings + '/host')
            port = settings.value(mySettings + '/port')
            password = settings.value(mySettings + '/password')
            uri = QgsDataSourceUri()
            uri.setConnection(host, str(port), dbname, user, password)
            uri.setDataSource(dlg.schema, dlg.table,
                              "the_geom" if isinstance(self.parameter, QgsProcessingParameterFeatureSink) and self.parameter.hasGeometry() else None)

            connInfo = uri.connectionInfo()
            (success, user, passwd) = QgsCredentials.instance().get(connInfo, None, None)
            if success:
                QgsCredentials.instance().put(connInfo, user, passwd)
            self.leText.setText("postgis:" + uri.uri())

            self.skipOutputChanged.emit(False)
            self.destinationChanged.emit()

    def execute(self):
        settings = QgsSettings()
        lastDir = settings.value('Processing/lastModelsDir', '')
        filename, selected_filter = QFileDialog.getOpenFileName(self.toolbox,
                                                                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())

                ModelerAlgorithm.fromFile(filename)
            except WrongModelException:
                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()

 def execute(self):
     settings = QgsSettings()
     lastDir = settings.value('Processing/lastScriptsDir', '')
     filenames, selected_filter = QFileDialog.getOpenFileNames(self.toolbox,
                                                               self.tr('Script files', 'AddScriptFromFileAction'), lastDir,
                                                               self.tr('Script files (*.py *.PY)', 'AddScriptFromFileAction'))
     if filenames:
         validAlgs = 0
         wrongAlgs = []
         for filename in filenames:
             try:
                 settings.setValue('Processing/lastScriptsDir',
                                   QFileInfo(filename).absoluteDir().absolutePath())
                 script = ScriptAlgorithm(filename)
                 destFilename = os.path.join(ScriptUtils.scriptsFolders()[0], os.path.basename(filename))
                 with open(destFilename, 'w') as f:
                     f.write(script.script)
                 validAlgs += 1
             except WrongScriptException:
                 wrongAlgs.append(os.path.basename(filename))
         if validAlgs:
             QgsApplication.processingRegistry().providerById('script').refreshAlgorithms()
         if wrongAlgs:
             QMessageBox.warning(self.toolbox,
                                 self.tr('Error reading scripts', 'AddScriptFromFileAction'),
                                 self.tr('The following files do not contain a valid script:\n-', 'AddScriptFromFileAction') +
                                 "\n-".join(wrongAlgs))

def createContext():
    """
    Creates a default processing context
    """
    context = QgsProcessingContext()
    context.setProject(QgsProject.instance())

    invalid_features_method = ProcessingConfig.getSetting(ProcessingConfig.FILTER_INVALID_GEOMETRIES)
    if invalid_features_method is None:
        invalid_features_method = QgsFeatureRequest.GeometryAbortOnInvalid
    context.setInvalidGeometryCheck(invalid_features_method)

    def raise_error(f):
        raise GeoAlgorithmExecutionException(QCoreApplication.translate("FeatureIterator",
                                                                        'Features with invalid geometries found. Please fix these geometries or specify the "Ignore invalid input features" flag'))

    context.setInvalidGeometryCallback(raise_error)

    def raise_transform_error(f):
        raise GeoAlgorithmExecutionException(QCoreApplication.translate("FeatureIterator",
                                                                        'Encountered a transform error when reprojecting feature with id {}.'.format(f.id())))
    context.setTransformErrorCallback(raise_transform_error)

    settings = QgsSettings()
    context.setDefaultEncoding(settings.value("/Processing/encoding", "System"))

    return context

def loadShortHelp():
    h = {}
    path = os.path.dirname(__file__)
    for f in os.listdir(path):
        if f.endswith("yaml"):
            filename = os.path.join(path, f)
            with codecs.open(filename, encoding='utf-8') as stream:
                with warnings.catch_warnings():
                    warnings.filterwarnings("ignore", category=DeprecationWarning)
                    for k, v in yaml.load(stream, Loader=yaml.SafeLoader).items():
                        if v is None:
                            continue
                        h[k] = QCoreApplication.translate("{}Algorithm".format(f[:-5].upper()), v)

    version = ".".join(Qgis.QGIS_VERSION.split(".")[0:2])
    overrideLocale = QgsSettings().value('locale/overrideFlag', False, bool)
    if not overrideLocale:
        locale = QLocale.system().name()[:2]
    else:
        locale = QgsSettings().value('locale/userLocale', '')
    locale = locale.split("_")[0]

    def replace(s):
        if s is not None:
            return s.replace("{qgisdocs}", "https://docs.qgis.org/%s/%s/docs" % (version, locale))
        else:
            return None

    h = {k: replace(v) for k, v in list(h.items())}

    return h

    def saveToGeopackage(self):
        file_filter = self.tr('GeoPackage files (*.gpkg);;All files (*.*)', 'OutputFile')

        settings = QgsSettings()
        if settings.contains('/Processing/LastOutputPath'):
            path = settings.value('/Processing/LastOutputPath')
        else:
            path = ProcessingConfig.getSetting(ProcessingConfig.OUTPUT_FOLDER)

        filename, filter = QFileDialog.getSaveFileName(self, self.tr("Save to GeoPackage"), path,
                                                       file_filter, options=QFileDialog.DontConfirmOverwrite)

        if not filename:
            return

        layer_name, ok = QInputDialog.getText(self, self.tr('Save to GeoPackage'), self.tr('Layer name'), text=self.parameter.name().lower())
        if ok:
            self.use_temporary = False
            if not filename.lower().endswith('.gpkg'):
                filename += '.gpkg'
            settings.setValue('/Processing/LastOutputPath',
                              os.path.dirname(filename))

            uri = QgsDataSourceUri()
            uri.setDatabase(filename)
            uri.setDataSource('', layer_name,
                              'geom' if isinstance(self.parameter, QgsProcessingParameterFeatureSink) and self.parameter.hasGeometry() else None)
            self.leText.setText("ogr:" + uri.uri())

            self.skipOutputChanged.emit(False)
            self.destinationChanged.emit()

    def showFileSelectionDialog(self):
        settings = QgsSettings()
        text = str(self.text.text())
        if os.path.isdir(text):
            path = text
        elif os.path.isdir(os.path.dirname(text)):
            path = os.path.dirname(text)
        elif settings.contains('/Processing/LastInputPath'):
            path = str(settings.value('/Processing/LastInputPath'))
        else:
            path = ''

        ret, selected_filter = QFileDialog.getOpenFileNames(self, self.tr('Select Files'), path,
                                                            getFileFilter(self.param))
        if ret:
            files = list(ret)
            settings.setValue('/Processing/LastInputPath',
                              os.path.dirname(str(files[0])))
            for i, filename in enumerate(files):
                files[i] = dataobjects.getRasterSublayer(filename, self.param)
            if len(files) == 1:
                self.text.setText(files[0])
                self.textEditingFinished()
            else:
                if isinstance(self.param, QgsProcessingParameterMultipleLayers):
                    self.text.setText(';'.join(str(f) for f in files))
                else:
                    rowdif = len(files) - (self._table().rowCount() - self.row)
                    for i in range(rowdif):
                        self._panel().addRow()
                    for i, f in enumerate(files):
                        self._table().cellWidget(i + self.row,
                                                 self.col).setValue(f)

    def getVectorWriter(self, fields, geomType, crs, context):
        """Returns a suitable writer to which features can be added as
        a result of the algorithm. Use this to transparently handle
        output values instead of creating your own method.

        Executing this method might modify the object, adding additional
        information to it, so the writer can be later accessed and
        processed within QGIS. It should be called just once, since a
        new call might result in previous data being replaced, thus
        rendering a previously obtained writer useless.

        @param fields   a list  of QgsField
        @param geomType a suitable geometry type, as it would be passed
                        to a QgsVectorFileWriter constructor
        @param crs      the crs of the layer to create

        @return writer  instance of the vector writer class
        :param context:
        """

        if self.encoding is None:
            settings = QgsSettings()
            self.encoding = settings.value('/Processing/encoding', 'System', str)

        w, w_dest = QgsProcessingUtils.createFeatureSink(self.value, context, fields, geomType, crs, {'fileEncoding': self.encoding})
        self.value = w_dest
        return w

def createContext(feedback=None):
    """
    Creates a default processing context

    :param feedback: Optional existing QgsProcessingFeedback object, or None to use a default feedback object
    :type feedback: Optional[QgsProcessingFeedback]

    :returns: New QgsProcessingContext object
    :rtype: QgsProcessingContext
    """
    context = QgsProcessingContext()
    context.setProject(QgsProject.instance())
    context.setFeedback(feedback)

    invalid_features_method = ProcessingConfig.getSetting(ProcessingConfig.FILTER_INVALID_GEOMETRIES)
    if invalid_features_method is None:
        invalid_features_method = QgsFeatureRequest.GeometryAbortOnInvalid
    context.setInvalidGeometryCheck(invalid_features_method)

    settings = QgsSettings()
    context.setDefaultEncoding(settings.value("/Processing/encoding", "System"))

    context.setExpressionContext(createExpressionContext())

    return context

    def __init__(self, alg, model, algName=None, configuration=None):
        QDialog.__init__(self)
        self.setModal(True)

        self._alg = alg # The algorithm to define in this dialog. It is an instance of QgsProcessingAlgorithm
        self.model = model # The model this algorithm is going to be added to. It is an instance of QgsProcessingModelAlgorithm
        self.childId = algName # The name of the algorithm in the model, in case we are editing it and not defining it for the first time
        self.configuration = configuration
        self.context = createContext()

        self.widget_labels = {}

        class ContextGenerator(QgsProcessingContextGenerator):

            def __init__(self, context):
                super().__init__()
                self.processing_context = context

            def processingContext(self):
                return self.processing_context

        self.context_generator = ContextGenerator(self.context)

        self.setupUi()
        self.params = None

        settings = QgsSettings()
        self.restoreGeometry(settings.value("/Processing/modelParametersDialogGeometry", QByteArray()))

    def reject(self):
        self.param = None

        settings = QgsSettings()
        settings.setValue("/Processing/modelParametersDefinitionDialogGeometry", self.saveGeometry())

        QDialog.reject(self)

 def save(self, qsettings=None):
     if not qsettings:
         qsettings = QgsSettings()
     if self.valuetype == self.SELECTION:
         qsettings.setValue(self.qname, self.options.index(self.value))
     else:
         qsettings.setValue(self.qname, self.value)

 def markNews(self):
     """ mark all new plugins as new """
     settings = QgsSettings()
     seenPlugins = settings.value(settingsGroup + '/seen_plugins', list(self.mPlugins.keys()), type=str)
     if len(seenPlugins) > 0:
         for i in list(self.mPlugins.keys()):
             if seenPlugins.count(i) == 0 and self.mPlugins[i]["status"] == "not installed":
                 self.mPlugins[i]["status"] = "new"

 def selectEncoding(self):
     dialog = QgsEncodingSelectionDialog(
         self, self.tr('File encoding'), self.encoding)
     if dialog.exec_() == QDialog.Accepted:
         self.encoding = dialog.encoding()
         settings = QgsSettings()
         settings.setValue('/Processing/encoding', self.encoding)
     dialog.deleteLater()

 def updateSeenPluginsList(self):
     """ update the list of all seen plugins """
     settings = QgsSettings()
     seenPlugins = settings.value(settingsGroup + '/seen_plugins', list(self.mPlugins.keys()), type=str)
     for i in list(self.mPlugins.keys()):
         if seenPlugins.count(i) == 0:
             seenPlugins += [i]
     settings.setValue(settingsGroup + '/seen_plugins', seenPlugins)

 def loadAPIFile(self):
     settings = QgsSettings()
     lastDirPath = settings.value("pythonConsole/lastDirAPIPath", "", type=str)
     fileAPI, selected_filter = QFileDialog.getOpenFileName(
         self, "Open API File", lastDirPath, "API file (*.api)")
     if fileAPI:
         self.addAPI(fileAPI)
         settings.setValue("pythonConsole/lastDirAPIPath", fileAPI)

 def setUp(self):
     self.cnt += 1
     h, path = tempfile.mkstemp('.ini')
     Path(path).touch()
     assert QgsSettings.setGlobalSettingsPath(path)
     self.settings = QgsSettings('testqgissettings', 'testqgissettings%s' % self.cnt)
     self.globalsettings = QSettings(self.settings.globalSettingsPath(), QSettings.IniFormat)
     self.globalsettings.sync()
     assert os.path.exists(self.globalsettings.fileName())

 def __init__(self, alg, paramType=None, param=None):
     self.alg = alg
     self.paramType = paramType
     self.param = param
     QDialog.__init__(self)
     self.setModal(True)
     self.setupUi()
     settings = QgsSettings()
     self.restoreGeometry(settings.value("/Processing/modelParametersDefinitionDialogGeometry", QByteArray()))