# -*- coding: utf-8 -*-
"""
***************************************************************************
FieldPyculator.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf at gmail 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__ = 'Victor Olaya & NextGIS'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya & NextGIS'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import sys
from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsProcessingException,
QgsField,
QgsFeatureSink,
QgsProcessing,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterString,
QgsProcessingParameterEnum,
QgsProcessingParameterNumber,
QgsProcessingParameterFeatureSink)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
class FieldsPyculator(QgisAlgorithm):
INPUT = 'INPUT'
FIELD_NAME = 'FIELD_NAME'
FIELD_TYPE = 'FIELD_TYPE'
FIELD_LENGTH = 'FIELD_LENGTH'
FIELD_PRECISION = 'FIELD_PRECISION'
GLOBAL = 'GLOBAL'
FORMULA = 'FORMULA'
OUTPUT = 'OUTPUT'
RESULT_VAR_NAME = 'value'
TYPES = [QVariant.LongLong, QVariant.Double, QVariant.String]
def group(self):
return self.tr('Vector table')
def groupId(self):
return 'vectortable'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.type_names = [self.tr('Integer'),
self.tr('Float'),
self.tr('String')]
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer'),
types=[QgsProcessing.TypeVector]))
self.addParameter(QgsProcessingParameterString(self.FIELD_NAME,
self.tr('Result field name'), defaultValue='NewField'))
self.addParameter(QgsProcessingParameterEnum(self.FIELD_TYPE,
self.tr('Field type'), options=self.type_names))
self.addParameter(QgsProcessingParameterNumber(self.FIELD_LENGTH,
self.tr('Field length'), minValue=1, maxValue=255,
defaultValue=10))
self.addParameter(QgsProcessingParameterNumber(self.FIELD_PRECISION,
self.tr('Field precision'), minValue=0, maxValue=15,
defaultValue=3))
self.addParameter(QgsProcessingParameterString(self.GLOBAL,
self.tr('Global expression'), multiLine=True, optional=True))
self.addParameter(QgsProcessingParameterString(self.FORMULA,
self.tr('Formula'), defaultValue='value = ', multiLine=True))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
self.tr('Calculated')))
def name(self):
return 'advancedpythonfieldcalculator'
def displayName(self):
return self.tr('Advanced Python field calculator')
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
field_name = self.parameterAsString(parameters, self.FIELD_NAME, context)
field_type = self.TYPES[self.parameterAsEnum(parameters, self.FIELD_TYPE, context)]
width = self.parameterAsInt(parameters, self.FIELD_LENGTH, context)
precision = self.parameterAsInt(parameters, self.FIELD_PRECISION, context)
code = self.parameterAsString(parameters, self.FORMULA, context)
globalExpression = self.parameterAsString(parameters, self.GLOBAL, context)
fields = source.fields()
field = QgsField(field_name, field_type, '', width, precision)
fields.append(field)
new_ns = {}
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, source.wkbType(), source.sourceCrs())
if sink is None:
raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
# Run global code
if globalExpression.strip() != '':
try:
bytecode = compile(globalExpression, '<string>', 'exec')
exec(bytecode, new_ns)
except:
raise QgsProcessingException(
self.tr("FieldPyculator code execute error.Global code block can't be executed!\n{0}\n{1}").format(
str(sys.exc_info()[0].__name__), str(sys.exc_info()[1])))
# Replace all fields tags
fields = source.fields()
num = 0
for field in fields:
field_name = str(field.name())
replval = '__attr[' + str(num) + ']'
code = code.replace('<' + field_name + '>', replval)
num += 1
# Replace all special vars
code = code.replace('$id', '__id')
code = code.replace('$geom', '__geom')
need_id = code.find('__id') != -1
need_geom = code.find('__geom') != -1
need_attrs = code.find('__attr') != -1
# Compile
try:
bytecode = compile(code, '<string>', 'exec')
except:
raise QgsProcessingException(
self.tr("FieldPyculator code execute error. Field code block can't be executed!\n{0}\n{1}").format(
str(sys.exc_info()[0].__name__), str(sys.exc_info()[1])))
# Run
features = source.getFeatures()
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, feat in enumerate(features):
if feedback.isCanceled():
break
feedback.setProgress(int(current * total))
attrs = feat.attributes()
feat_id = feat.id()
# Add needed vars
if need_id:
new_ns['__id'] = feat_id
if need_geom:
geom = feat.geometry()
new_ns['__geom'] = geom
if need_attrs:
pyattrs = [a for a in attrs]
new_ns['__attr'] = pyattrs
# Clear old result
if self.RESULT_VAR_NAME in new_ns:
del new_ns[self.RESULT_VAR_NAME]
# Exec
exec(bytecode, new_ns)
# Check result
if self.RESULT_VAR_NAME not in new_ns:
raise QgsProcessingException(
self.tr("FieldPyculator code execute error\n"
"Field code block does not return '{0}' variable! "
"Please declare this variable in your code!").format(self.RESULT_VAR_NAME))
# Write feature
attrs.append(new_ns[self.RESULT_VAR_NAME])
feat.setAttributes(attrs)
sink.addFeature(feat, QgsFeatureSink.FastInsert)
return {self.OUTPUT: dest_id}
def checkParameterValues(self, parameters, context):
# TODO check that formula is correct and fields exist
return super(FieldsPyculator, self).checkParameterValues(parameters, context)