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06c4b07222
Since the layer has more complete knowledge of the crs (ie, when provider could not determine crs and user has selected it from the list), and also better knowledge of layer fields (virtual fields, joined fields) we should use these rather than the provider methods.
176 lines
7.1 KiB
Python
176 lines
7.1 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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FieldPyculator.py
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---------------------
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Date : August 2012
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Copyright : (C) 2012 by Victor Olaya
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Email : volayaf at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Victor Olaya & NextGIS'
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__date__ = 'August 2012'
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__copyright__ = '(C) 2012, Victor Olaya & NextGIS'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import sys
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import QgsFeature, QgsField
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterString
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from processing.core.parameters import ParameterNumber
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from processing.core.parameters import ParameterSelection
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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class FieldsPyculator(GeoAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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FIELD_NAME = 'FIELD_NAME'
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FIELD_TYPE = 'FIELD_TYPE'
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FIELD_LENGTH = 'FIELD_LENGTH'
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FIELD_PRECISION = 'FIELD_PRECISION'
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GLOBAL = 'GLOBAL'
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FORMULA = 'FORMULA'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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RESULT_VAR_NAME = 'value'
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TYPES = [QVariant.Int, QVariant.Double, QVariant.String]
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Advanced Python field calculator')
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self.group, self.i18n_group = self.trAlgorithm('Vector table tools')
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self.type_names = [self.tr('Integer'),
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self.tr('Float'),
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self.tr('String')]
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self.addParameter(ParameterVector(self.INPUT_LAYER,
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self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_ANY], False))
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self.addParameter(ParameterString(self.FIELD_NAME,
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self.tr('Result field name'), 'NewField'))
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self.addParameter(ParameterSelection(self.FIELD_TYPE,
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self.tr('Field type'), self.type_names))
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self.addParameter(ParameterNumber(self.FIELD_LENGTH,
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self.tr('Field length'), 1, 255, 10))
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self.addParameter(ParameterNumber(self.FIELD_PRECISION,
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self.tr('Field precision'), 0, 10, 0))
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self.addParameter(ParameterString(self.GLOBAL,
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self.tr('Global expression'), multiline=True, optional=True))
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self.addParameter(ParameterString(self.FORMULA,
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self.tr('Formula'), 'value = ', multiline=True))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Calculated')))
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def processAlgorithm(self, progress):
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fieldName = self.getParameterValue(self.FIELD_NAME)
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fieldType = self.getParameterValue(self.FIELD_TYPE)
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fieldLength = self.getParameterValue(self.FIELD_LENGTH)
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fieldPrecision = self.getParameterValue(self.FIELD_PRECISION)
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code = self.getParameterValue(self.FORMULA)
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globalExpression = self.getParameterValue(self.GLOBAL)
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output = self.getOutputFromName(self.OUTPUT_LAYER)
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT_LAYER))
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fields = layer.fields()
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fields.append(QgsField(fieldName, self.TYPES[fieldType], '',
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fieldLength, fieldPrecision))
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writer = output.getVectorWriter(fields, layer.wkbType(),
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layer.crs())
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outFeat = QgsFeature()
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new_ns = {}
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# Run global code
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if globalExpression.strip() != '':
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try:
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bytecode = compile(globalExpression, '<string>', 'exec')
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exec(bytecode, new_ns)
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except:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error.Global code block can't be executed!\n%s\n%s") % (unicode(sys.exc_info()[0].__name__), unicode(sys.exc_info()[1])))
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# Replace all fields tags
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fields = layer.fields()
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num = 0
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for field in fields:
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field_name = unicode(field.name())
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replval = '__attr[' + unicode(num) + ']'
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code = code.replace('<' + field_name + '>', replval)
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num += 1
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# Replace all special vars
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code = code.replace('$id', '__id')
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code = code.replace('$geom', '__geom')
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need_id = code.find('__id') != -1
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need_geom = code.find('__geom') != -1
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need_attrs = code.find('__attr') != -1
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# Compile
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try:
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bytecode = compile(code, '<string>', 'exec')
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except:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error.Field code block can't be executed!\n%s\n%s") % (unicode(sys.exc_info()[0].__name__), unicode(sys.exc_info()[1])))
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# Run
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, feat in enumerate(features):
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progress.setPercentage(int(current * total))
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attrs = feat.attributes()
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feat_id = feat.id()
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# Add needed vars
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if need_id:
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new_ns['__id'] = feat_id
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if need_geom:
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geom = feat.geometry()
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new_ns['__geom'] = geom
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if need_attrs:
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pyattrs = [a for a in attrs]
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new_ns['__attr'] = pyattrs
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# Clear old result
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if self.RESULT_VAR_NAME in new_ns:
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del new_ns[self.RESULT_VAR_NAME]
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# Exec
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exec(bytecode, new_ns)
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# Check result
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if self.RESULT_VAR_NAME not in new_ns:
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raise GeoAlgorithmExecutionException(
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self.tr("FieldPyculator code execute error\n"
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"Field code block does not return '%s1' variable! "
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"Please declare this variable in your code!") % self.RESULT_VAR_NAME)
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# Write feature
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outFeat.setGeometry(feat.geometry())
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attrs.append(new_ns[self.RESULT_VAR_NAME])
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outFeat.setAttributes(attrs)
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writer.addFeature(outFeat)
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del writer
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def checkParameterValuesBeforeExecuting(self):
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# TODO check that formula is correct and fields exist
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pass
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