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a05d941e4e
Since the underlying issues with the Python bindings are now fixed, in most cases we can safely default to allowing an algorithm to run in a background thread!! So now we make this the default, and require individual algorithms which are NOT thread safe to declare this. This includes algorithms which directly manipulate the current project or layers (such as setting layer styles), alter the selections in layers, or which rely on 3rd party libraries (for now, SAGA and GRASS algorithms are marked as not thread safe... TODO - someone more familiar with these libraries can investigate and remove the flag if appropriate). Also models are marked as non-thread safe. TODO: only flag an individual model as thread-unsafe if any of its child algorithms report this flag.
154 lines
6.4 KiB
Python
154 lines
6.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ExecuteSQL.py -- use virtual layers to execute SQL on any sources
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---------------------
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Date : Jan 2016
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Copyright : (C) 2016 by Hugo Mercier
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Email : hugo dot mercier at oslandia 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__ = 'Hugo Mercier'
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__date__ = 'January 2016'
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__copyright__ = '(C) 2016, Hugo Mercier'
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# This will get replaced with a git SHA1 when you do a git archive323
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__revision__ = '$Format:%H$'
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from qgis.core import (QgsVirtualLayerDefinition,
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QgsVectorLayer,
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QgsWkbTypes,
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QgsProcessingAlgorithm,
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QgsProcessingParameterMultipleLayers,
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QgsProcessingParameterString,
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QgsProcessingParameterEnum,
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QgsProcessingParameterCrs,
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QgsProcessingParameterFeatureSink,
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QgsFeatureSink,
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QgsProcessingException)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class ExecuteSQL(QgisAlgorithm):
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""" This algorithm allows executing an SQL query on a set of input
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vector layers thanks to the virtual layer provider
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"""
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INPUT_DATASOURCES = 'INPUT_DATASOURCES'
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INPUT_QUERY = 'INPUT_QUERY'
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INPUT_UID_FIELD = 'INPUT_UID_FIELD'
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INPUT_GEOMETRY_FIELD = 'INPUT_GEOMETRY_FIELD'
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INPUT_GEOMETRY_TYPE = 'INPUT_GEOMETRY_TYPE'
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INPUT_GEOMETRY_CRS = 'INPUT_GEOMETRY_CRS'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector general')
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def groupId(self):
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return 'vectorgeneral'
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def __init__(self):
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super().__init__()
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def flags(self):
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return super().flags() | QgsProcessingAlgorithm.FlagNoThreading
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterMultipleLayers(name=self.INPUT_DATASOURCES,
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description=self.tr('Additional input datasources (called input1, .., inputN in the query)'),
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optional=True))
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self.addParameter(QgsProcessingParameterString(name=self.INPUT_QUERY,
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description=self.tr('SQL query'),
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multiLine=True))
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self.addParameter(QgsProcessingParameterString(name=self.INPUT_UID_FIELD,
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description=self.tr('Unique identifier field'), optional=True))
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self.addParameter(QgsProcessingParameterString(name=self.INPUT_GEOMETRY_FIELD,
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description=self.tr('Geometry field'), optional=True))
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self.geometryTypes = [
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self.tr('Autodetect'),
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self.tr('No geometry'),
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'Point',
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'LineString',
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'Polygon',
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'MultiPoint',
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'MultiLineString',
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'MultiPolygon']
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self.addParameter(QgsProcessingParameterEnum(self.INPUT_GEOMETRY_TYPE,
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self.tr('Geometry type'), options=self.geometryTypes, optional=True))
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self.addParameter(QgsProcessingParameterCrs(self.INPUT_GEOMETRY_CRS,
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self.tr('CRS'), optional=True))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('SQL Output')))
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def name(self):
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return 'executesql'
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def displayName(self):
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return self.tr('Execute SQL')
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def processAlgorithm(self, parameters, context, feedback):
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layers = self.parameterAsLayerList(parameters, self.INPUT_DATASOURCES, context)
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query = self.parameterAsString(parameters, self.INPUT_QUERY, context)
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uid_field = self.parameterAsString(parameters, self.INPUT_UID_FIELD, context)
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geometry_field = self.parameterAsString(parameters, self.INPUT_GEOMETRY_FIELD, context)
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geometry_type = self.parameterAsEnum(parameters, self.INPUT_GEOMETRY_TYPE, context)
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geometry_crs = self.parameterAsCrs(parameters, self.INPUT_GEOMETRY_CRS, context)
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df = QgsVirtualLayerDefinition()
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for layerIdx, layer in enumerate(layers):
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df.addSource('input{}'.format(layerIdx + 1), layer.id())
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if query == '':
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raise QgsProcessingException(
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self.tr('Empty SQL. Please enter valid SQL expression and try again.'))
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else:
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df.setQuery(query)
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if uid_field:
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df.setUid(uid_field)
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if geometry_type == 1: # no geometry
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df.setGeometryWkbType(QgsWkbTypes.NullGeometry)
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else:
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if geometry_field:
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df.setGeometryField(geometry_field)
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if geometry_type > 1:
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df.setGeometryWkbType(geometry_type - 1)
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if geometry_crs.isValid():
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df.setGeometrySrid(geometry_crs.postgisSrid())
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vLayer = QgsVectorLayer(df.toString(), "temp_vlayer", "virtual")
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if not vLayer.isValid():
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raise QgsProcessingException(vLayer.dataProvider().error().message())
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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vLayer.fields(), vLayer.wkbType() if geometry_type != 1 else 1, vLayer.crs())
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features = vLayer.getFeatures()
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total = 100.0 / vLayer.featureCount() if vLayer.featureCount() else 0
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for current, inFeat in enumerate(features):
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if feedback.isCanceled():
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break
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sink.addFeature(inFeat, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(current * total))
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return {self.OUTPUT: dest_id}
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