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"""
***************************************************************************
Datasources2Vrt.py
---------------------
Date : May 2015
Copyright : (C) 2015 by Luigi Pirelli
Email : luipir 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__ = "Luigi Pirelli"
__date__ = "May 2015"
__copyright__ = "(C) 2015, Luigi Pirelli"
import html
import pathlib
from qgis.PyQt.QtCore import QCoreApplication
from qgis.core import (
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterMultipleLayers,
QgsProcessingParameterBoolean,
QgsProcessingParameterVectorDestination,
QgsProcessingOutputString,
QgsProcessingParameters,
)
from processing.algs.gdal.GdalAlgorithm import GdalAlgorithm
from processing.algs.gdal.GdalUtils import GdalUtils
class Datasources2Vrt(GdalAlgorithm):
INPUT = "INPUT"
UNIONED = "UNIONED"
OUTPUT = "OUTPUT"
VRT_STRING = "VRT_STRING"
def createCustomParametersWidget(self, parent):
return None
def group(self):
return self.tr("Vector miscellaneous")
def groupId(self):
return "vectormiscellaneous"
def name(self):
return "buildvirtualvector"
def displayName(self):
return self.tr("Build virtual vector")
def tags(self):
return ["ogr", "gdal", "vrt", "create"]
def shortHelpString(self):
return self.tr(
"This algorithm creates a virtual layer that contains a set of vector layers.\n\n"
"The output virtual layer will not be opened in the current project."
)
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(
QgsProcessingParameterMultipleLayers(
self.INPUT,
self.tr("Input datasources"),
QgsProcessing.SourceType.TypeVector,
)
)
self.addParameter(
QgsProcessingParameterBoolean(
self.UNIONED, self.tr('Create "unioned" VRT'), defaultValue=False
)
)
class ParameterVectorVrtDestination(QgsProcessingParameterVectorDestination):
def __init__(self, name, description):
super().__init__(name, description)
def clone(self):
copy = ParameterVectorVrtDestination(self.name(), self.description())
return copy
def defaultFileExtension(self):
return "vrt"
def createFileFilter(self):
return "{} (*.vrt *.VRT)".format(
QCoreApplication.translate("GdalAlgorithm", "VRT files")
)
def supportedOutputRasterLayerExtensions(self):
return ["vrt"]
def isSupportedOutputValue(self, value, context):
output_path = QgsProcessingParameters.parameterAsOutputLayer(
self, value, context, testOnly=True
)
if pathlib.Path(output_path).suffix.lower() != ".vrt":
return False, QCoreApplication.translate(
"GdalAlgorithm", "Output filename must use a .vrt extension"
)
return True, ""
self.addParameter(
ParameterVectorVrtDestination(self.OUTPUT, self.tr("Virtual vector"))
)
self.addOutput(
QgsProcessingOutputString(self.VRT_STRING, self.tr("Virtual string"))
)
def processAlgorithm(self, parameters, context, feedback):
input_layers = self.parameterAsLayerList(parameters, self.INPUT, context)
unioned = self.parameterAsBoolean(parameters, self.UNIONED, context)
vrtPath = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
vrt = "<OGRVRTDataSource>"
if unioned:
vrt += '<OGRVRTUnionLayer name="UnionedLayer">'
total = 100.0 / len(input_layers) if input_layers else 0
for current, layer in enumerate(input_layers):
if feedback.isCanceled():
break
connection_details = GdalUtils.gdal_connection_details_from_layer(layer)
basePath = connection_details.connection_string
layerName = GdalUtils.ogrLayerName(layer.source())
vrt += f'<OGRVRTLayer name="{html.escape(layerName, True)}">'
vrt += f"<SrcDataSource>{html.escape(basePath, True)}</SrcDataSource>"
vrt += f"<SrcLayer>{html.escape(layerName, True)}</SrcLayer>"
vrt += "</OGRVRTLayer>"
feedback.setProgress(int(current * total))
if unioned:
vrt += "</OGRVRTUnionLayer>"
vrt += "</OGRVRTDataSource>"
with open(vrtPath, "w", encoding="utf-8") as f:
f.write(vrt)
return {self.OUTPUT: vrtPath, self.VRT_STRING: vrt}
def commandName(self):
return ""
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