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# -*- coding: utf-8 -*-
"""
***************************************************************************
FieldsMapper.py
---------------------
Date : October 2014
Copyright : (C) 2014 by Arnaud Morvan
Email : arnaud dot morvan at camptocamp 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. *
* *
***************************************************************************
"""
__author__ = 'Arnaud Morvan'
__date__ = 'October 2014'
__copyright__ = '(C) 2014, Arnaud Morvan'
from qgis.core import (
QgsDistanceArea,
QgsExpression,
QgsField,
QgsFields,
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterDefinition,
QgsProcessingParameterType,
NULL)
from qgis.PyQt.QtCore import QCoreApplication
from processing.algs.qgis.QgisAlgorithm import QgisFeatureBasedAlgorithm
class FieldsMapper(QgisFeatureBasedAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
FIELDS_MAPPING = 'FIELDS_MAPPING'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def group(self):
return self.tr('Vector table')
def groupId(self):
return 'vectortable'
def tags(self):
return self.tr('attributes,table').split(',')
def initParameters(self, config=None):
fields_mapping = FieldsMapper.ParameterFieldsMapping(self.FIELDS_MAPPING,
description=self.tr('Fields mapping'))
fields_mapping.setMetadata({
'widget_wrapper': 'processing.algs.qgis.ui.FieldsMappingPanel.FieldsMappingWidgetWrapper'
})
self.addParameter(fields_mapping)
def name(self):
return 'refactorfields'
def displayName(self):
return self.tr('Refactor fields')
def outputName(self):
return self.tr('Refactored')
def inputLayerTypes(self):
return [QgsProcessing.TypeVector]
def parameterAsFieldsMapping(self, parameters, name, context):
return parameters[name]
def supportInPlaceEdit(self, layer):
return False
def prepareAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, 'INPUT', context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, 'INPUT'))
mapping = self.parameterAsFieldsMapping(parameters, self.FIELDS_MAPPING, context)
self.fields = QgsFields()
self.expressions = []
da = QgsDistanceArea()
da.setSourceCrs(source.sourceCrs(), context.transformContext())
da.setEllipsoid(context.project().ellipsoid())
# create an expression context using thread safe processing context
self.expr_context = self.createExpressionContext(parameters, context, source)
for field_def in mapping:
self.fields.append(QgsField(name=field_def['name'],
type=field_def['type'],
typeName="",
len=field_def.get('length', 0),
prec=field_def.get('precision', 0)))
if field_def['expression']:
expression = QgsExpression(field_def['expression'])
expression.setGeomCalculator(da)
expression.setDistanceUnits(context.project().distanceUnits())
expression.setAreaUnits(context.project().areaUnits())
if expression.hasParserError():
feedback.reportError(
self.tr(u'Parser error in expression "{}": {}')
.format(expression.expression(),
expression.parserErrorString()))
return False
self.expressions.append(expression)
else:
self.expressions.append(None)
return True
def outputFields(self, inputFields):
return self.fields
def processAlgorithm(self, parameters, context, feeback):
for expression in self.expressions:
if expression is not None:
expression.prepare(self.expr_context)
self._row_number = 0
return super().processAlgorithm(parameters, context, feeback)
def processFeature(self, feature, context, feedback):
attributes = []
for expression in self.expressions:
if expression is not None:
self.expr_context.setFeature(feature)
self.expr_context.lastScope().setVariable("row_number", self._row_number)
value = expression.evaluate(self.expr_context)
if expression.hasEvalError():
raise QgsProcessingException(
self.tr(u'Evaluation error in expression "{}": {}')
.format(expression.expression(),
expression.evalErrorString()))
attributes.append(value)
else:
attributes.append(NULL)
feature.setAttributes(attributes)
self._row_number += 1
return [feature]
class ParameterFieldsMappingType(QgsProcessingParameterType):
def __init__(self):
super().__init__()
def create(self, name):
return FieldsMapper.ParameterFieldsMapping(name)
def metadata(self):
return {'widget_wrapper': 'processing.algs.qgis.ui.FieldsMappingPanel.FieldsMappingWidgetWrapper'}
def name(self):
return QCoreApplication.translate('Processing', 'Fields Mapper')
def id(self):
return 'fields_mapping'
def pythonImportString(self):
return 'from processing.algs.qgis.FieldsMapper import FieldsMapper'
def className(self):
return 'FieldsMapper.ParameterFieldsMapping'
def description(self):
return QCoreApplication.translate('Processing', 'A mapping of field names to field type definitions and expressions. Used for the refactor fields algorithm.')
class ParameterFieldsMapping(QgsProcessingParameterDefinition):
def __init__(self, name, description='', parentLayerParameterName='INPUT'):
super().__init__(name, description)
self._parentLayerParameter = parentLayerParameterName
def clone(self):
copy = FieldsMapper.ParameterFieldsMapping(self.name(), self.description(), self._parentLayerParameter)
return copy
def type(self):
return self.typeName()
@staticmethod
def typeName():
return 'fields_mapping'
def checkValueIsAcceptable(self, value, context=None):
if not isinstance(value, list):
return False
for field_def in value:
if not isinstance(field_def, dict):
return False
if 'name' not in field_def.keys():
return False
if 'type' not in field_def.keys():
return False
if 'expression' not in field_def.keys():
return False
return True
def valueAsPythonString(self, value, context):
return str(value)
def asScriptCode(self):
raise NotImplementedError()
@classmethod
def fromScriptCode(cls, name, description, isOptional, definition):
raise NotImplementedError()
def parentLayerParameter(self):
return self._parentLayerParameter