Move expression context generation out of parameters

Author: nyalldawson

python/plugins/processing/core/GeoAlgorithm.py

@@ -120,7 +120,6 @@ def execute(self, parameters, context=None, feedback=None, model=None):
         try:
             self.setOutputCRS()
             self.resolveOutputs()
-            self.evaluateParameterValues()
             self.runPreExecutionScript(feedback)
             self.processAlgorithm(parameters, context, feedback)
             feedback.setProgress(100)
@@ -229,14 +228,6 @@ def getFormatShortNameFromFilename(self, filename):
                 return name
         return 'GTiff'
 
-    def evaluateParameterValues(self):
-        for param in self.parameters:
-            try:
-                param.evaluate(self)
-            except ValueError as e:
-                traceback.print_exc()
-                raise GeoAlgorithmExecutionException(str(e))
-
     def resolveOutputs(self):
         """Sets temporary outputs (output.value = None) with a
         temporary file instead. Resolves expressions as well.

python/plugins/processing/core/parameters.py

@@ -37,10 +37,10 @@
 import numbers
 
 from qgis.core import QgsProcessingUtils
-from qgis.utils import iface
+
 from qgis.PyQt.QtCore import QCoreApplication
 from qgis.core import (QgsRasterLayer, QgsVectorLayer, QgsMapLayer, QgsCoordinateReferenceSystem,
-                       QgsExpressionContext, QgsExpressionContextUtils, QgsExpression, QgsExpressionContextScope,
+                       QgsExpression,
                        QgsProject,
                        QgsRectangle,
                        QgsVectorFileWriter,
@@ -72,25 +72,6 @@ def _createDescriptiveName(s):
     return s.replace('_', ' ')
 
 
-def _expressionContext():
-    context = QgsExpressionContext()
-    context.appendScope(QgsExpressionContextUtils.globalScope())
-    context.appendScope(QgsExpressionContextUtils.projectScope(QgsProject.instance()))
-
-    if iface.mapCanvas():
-        context.appendScope(QgsExpressionContextUtils.mapSettingsScope(iface.mapCanvas().mapSettings()))
-
-    processingScope = QgsExpressionContextScope()
-
-    extent = iface.mapCanvas().fullExtent()
-    processingScope.setVariable('fullextent_minx', extent.xMinimum())
-    processingScope.setVariable('fullextent_miny', extent.yMinimum())
-    processingScope.setVariable('fullextent_maxx', extent.xMaximum())
-    processingScope.setVariable('fullextent_maxy', extent.yMaximum())
-    context.appendScope(processingScope)
-    return context
-
-
 class Parameter(object):
 
     """
@@ -139,9 +120,6 @@ def tr(self, string, context=''):
             context = 'Parameter'
         return QCoreApplication.translate(context, string)
 
-    def evaluate(self, alg):
-        pass
-
 
 class ParameterBoolean(Parameter):
 
@@ -726,8 +704,7 @@ def setValue(self, n):
 
         if isinstance(n, str):
             try:
-                v = self._evaluate(n)
-                self.value = float(v)
+                self.value = float(n)
                 if self.isInteger:
                     self.value = int(math.floor(self.value))
                 return True
@@ -772,22 +749,6 @@ def fromScriptCode(self, line):
                 default = None
             return ParameterNumber(name, descName, default=default, optional=isOptional)
 
-    def _evaluate(self, value):
-        exp = QgsExpression(value)
-        if exp.hasParserError():
-            raise ValueError(self.tr("Error in parameter expression: ") + exp.parserErrorString())
-        result = exp.evaluate(_expressionContext())
-        if exp.hasEvalError():
-            raise ValueError("Error evaluating parameter expression: " + exp.evalErrorString())
-        if self.isInteger:
-            return math.floor(result)
-        else:
-            return result
-
-    def evaluate(self, alg):
-        if isinstance(self.value, str) and bool(self.value):
-            self.value = self._evaluate(self.value)
-
     def _layerVariables(self, element, alg=None):
         variables = {}
         context = dataobjects.createContext()
@@ -827,9 +788,6 @@ def evaluateForModeler(self, value, model):
 
         return value
 
-    def expressionContext(self):
-        return _expressionContext()
-
     def getValueAsCommandLineParameter(self):
         if self.value is None:
             return str(None)
@@ -1070,7 +1028,6 @@ def __init__(self, name='', description='', default=None, multiline=False,
                  optional=False, evaluateExpressions=False, metadata={}):
         Parameter.__init__(self, name, description, default, optional, metadata)
         self.multiline = parseBool(multiline)
-        self.evaluateExpressions = parseBool(evaluateExpressions)
 
     def setValue(self, obj):
         if not bool(obj):
@@ -1118,19 +1075,6 @@ def fromScriptCode(self, line):
             else:
                 return ParameterString(name, descName, multiline=True, optional=isOptional)
 
-    def evaluate(self, alg):
-        if isinstance(self.value, str) and bool(self.value) and self.evaluateExpressions:
-            exp = QgsExpression(self.value)
-            if exp.hasParserError():
-                raise ValueError(self.tr("Error in parameter expression: ") + exp.parserErrorString())
-            result = exp.evaluate(_expressionContext())
-            if exp.hasEvalError():
-                raise ValueError("Error evaluating parameter expression: " + exp.evalErrorString())
-            self.value = result
-
-    def expressionContext(self):
-        return _expressionContext()
-
 
 class ParameterExpression(Parameter):
 

python/plugins/processing/gui/NumberInputPanel.py

@@ -39,6 +39,7 @@
 from processing.core.parameters import ParameterNumber, ParameterVector, ParameterRaster
 from processing.core.outputs import OutputNumber, OutputVector, OutputRaster
 from processing.modeler.ModelerAlgorithm import ValueFromInput, ValueFromOutput, CompoundValue
+from processing.tools.dataobjects import createExpressionContext
 
 pluginPath = os.path.split(os.path.dirname(__file__))[0]
 NUMBER_WIDGET, NUMBER_BASE = uic.loadUiType(
@@ -48,6 +49,7 @@
 
 
 class ModellerNumberInputPanel(BASE, WIDGET):
+
     """
     Number input panel for use inside the modeller - this input panel
     is based off the base input panel and includes a text based line input
@@ -70,7 +72,7 @@ def __init__(self, param, modelParametersDialog):
         self.leText.textChanged.connect(lambda: self.hasChanged.emit())
 
     def showExpressionsBuilder(self):
-        context = self.param.expressionContext()
+        context = createExpressionContext()
         dlg = QgsExpressionBuilderDialog(None, str(self.leText.text()), self, 'generic', context)
 
         context.popScope()
@@ -138,6 +140,7 @@ def setValue(self, value):
 
 
 class NumberInputPanel(NUMBER_BASE, NUMBER_WIDGET):
+
     """
     Number input panel for use outside the modeller - this input panel
     contains a user friendly spin box for entering values. It also
@@ -195,7 +198,7 @@ def __init__(self, param):
         self.spnValue.valueChanged.connect(lambda: self.hasChanged.emit())
 
     def showExpressionsBuilder(self):
-        context = self.param.expressionContext()
+        context = createExpressionContext()
         dlg = QgsExpressionBuilderDialog(None, str(self.spnValue.value()), self, 'generic', context)
 
         dlg.setWindowTitle(self.tr('Expression based input'))

python/plugins/processing/gui/wrappers.py

@@ -230,7 +230,7 @@ def wrapWithExpressionButton(self, basewidget):
         return widget
 
     def showExpressionsBuilder(self):
-        context = self.param.expressionContext()
+        context = dataobjects.createExpressionContext()
         value = self.value()
         if not isinstance(value, str):
             value = ''

python/plugins/processing/tools/dataobjects.py

@@ -40,9 +40,13 @@
                        QgsSettings,
                        QgsProcessingUtils,
                        QgsProcessingContext,
-                       QgsFeatureRequest)
+                       QgsFeatureRequest,
+                       QgsExpressionContext,
+                       QgsExpressionContextUtils,
+                       QgsExpressionContextScope)
 from qgis.gui import QgsSublayersDialog
 from qgis.PyQt.QtCore import QCoreApplication
+from qgis.utils import iface
 
 from processing.core.ProcessingConfig import ProcessingConfig
 from processing.algs.gdal.GdalUtils import GdalUtils
@@ -91,6 +95,25 @@ def raise_error(f):
     return context
 
 
+def createExpressionContext():
+    context = QgsExpressionContext()
+    context.appendScope(QgsExpressionContextUtils.globalScope())
+    context.appendScope(QgsExpressionContextUtils.projectScope(QgsProject.instance()))
+
+    if iface.mapCanvas():
+        context.appendScope(QgsExpressionContextUtils.mapSettingsScope(iface.mapCanvas().mapSettings()))
+
+    processingScope = QgsExpressionContextScope()
+
+    extent = iface.mapCanvas().fullExtent()
+    processingScope.setVariable('fullextent_minx', extent.xMinimum())
+    processingScope.setVariable('fullextent_miny', extent.yMinimum())
+    processingScope.setVariable('fullextent_maxx', extent.xMaximum())
+    processingScope.setVariable('fullextent_maxy', extent.yMaximum())
+    context.appendScope(processingScope)
+    return context
+
+
 def getSupportedOutputRasterLayerExtensions():
     allexts = []
     for exts in list(GdalUtils.getSupportedRasters().values()):