QGIS API Documentation 3.34.0-Prizren (ffbdd678812)
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qgsalgorithmsavefeatures.cpp
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1/***************************************************************************
2 qgsalgorithmsavefeatures.cpp
3 ---------------------
4 begin : July 2020
5 copyright : (C) 2020 by Mathieu Pellerin
6 email : nirvn dot asia at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
19#include "qgsvectorfilewriter.h"
20#include <QRegularExpression>
21
23
24QString QgsSaveFeaturesAlgorithm::name() const
25{
26 return QStringLiteral( "savefeatures" );
27}
28
29QString QgsSaveFeaturesAlgorithm::displayName() const
30{
31 return QObject::tr( "Save vector features to file" );
32}
33
34QStringList QgsSaveFeaturesAlgorithm::tags() const
35{
36 return QObject::tr( "save,write,export" ).split( ',' );
37}
38
39QString QgsSaveFeaturesAlgorithm::group() const
40{
41 return QObject::tr( "Vector general" );
42}
43
44QString QgsSaveFeaturesAlgorithm::groupId() const
45{
46 return QStringLiteral( "vectorgeneral" );
47}
48
49QString QgsSaveFeaturesAlgorithm::shortHelpString() const
50{
51 return QObject::tr( "This algorithm saves vector features to a specified file dataset.\n\n"
52 "For dataset formats supporting layers, an optional layer name parameter can be used to specify a custom string.\n\n"
53 "Optional GDAL-defined dataset and layer options can be specified. For more information on this, "
54 "read the online GDAL documentation." );
55}
56
57QgsSaveFeaturesAlgorithm *QgsSaveFeaturesAlgorithm::createInstance() const
58{
59 return new QgsSaveFeaturesAlgorithm();
60}
61
62void QgsSaveFeaturesAlgorithm::initAlgorithm( const QVariantMap & )
63{
64 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Vector features" ), QList<int>() << QgsProcessing::TypeVector ) );
65 addParameter( new QgsProcessingParameterFileDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Saved features" ), QgsVectorFileWriter::fileFilterString(), QVariant(), false ) );
66
67 std::unique_ptr< QgsProcessingParameterString > param = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "LAYER_NAME" ), QObject::tr( "Layer name" ), QVariant(), false, true );
68 param->setFlags( param->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
69 addParameter( param.release() );
70 param = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "DATASOURCE_OPTIONS" ), QObject::tr( "GDAL dataset options (separate individual options with semicolons)" ), QVariant(), false, true );
71 param->setFlags( param->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
72 addParameter( param.release() );
73 param = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "LAYER_OPTIONS" ), QObject::tr( "GDAL layer options (separate individual options with semicolons)" ), QVariant(), false, true );
74 param->setFlags( param->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
75 addParameter( param.release() );
76
77 std::unique_ptr< QgsProcessingParameterEnum > paramEnum = std::make_unique< QgsProcessingParameterEnum >( QStringLiteral( "ACTION_ON_EXISTING_FILE" ), QObject::tr( "Action to take on pre-existing file" ), QStringList() << QObject::tr( "Create or overwrite file" ) << QObject::tr( "Create or overwrite layer" ) << QObject::tr( "Append features to existing layer, but do not create new fields" ) << QObject::tr( "Append features to existing layer, and create new fields if needed" ), false, 0 );
78 paramEnum->setFlags( paramEnum->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
79 addParameter( paramEnum.release() );
80
81 addOutput( new QgsProcessingOutputString( QStringLiteral( "FILE_PATH" ), QObject::tr( "File name and path" ) ) );
82 addOutput( new QgsProcessingOutputString( QStringLiteral( "LAYER_NAME" ), QObject::tr( "Layer name" ) ) );
83}
84
85QVariantMap QgsSaveFeaturesAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
86{
87 std::unique_ptr< QgsProcessingFeatureSource > source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
88
89 QString layerName = parameterAsString( parameters, QStringLiteral( "LAYER_NAME" ), context ).trimmed();
90 QVariantMap createOptions;
91 if ( !layerName.isEmpty() )
92 {
93 createOptions[QStringLiteral( "layerName" )] = layerName;
94 }
95
96#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
97 QStringList datasourceOptions = parameterAsString( parameters, QStringLiteral( "DATASOURCE_OPTIONS" ), context ).trimmed().split( ';', QString::SkipEmptyParts );
98 QStringList layerOptions = parameterAsString( parameters, QStringLiteral( "LAYER_OPTIONS" ), context ).trimmed().split( ';', QString::SkipEmptyParts );
99#else
100 const QStringList datasourceOptions = parameterAsString( parameters, QStringLiteral( "DATASOURCE_OPTIONS" ), context ).trimmed().split( ';', Qt::SkipEmptyParts );
101 const QStringList layerOptions = parameterAsString( parameters, QStringLiteral( "LAYER_OPTIONS" ), context ).trimmed().split( ';', Qt::SkipEmptyParts );
102#endif
103
104 QString destination = parameterAsString( parameters, QStringLiteral( "OUTPUT" ), context );
105 const QString format = QgsVectorFileWriter::driverForExtension( QFileInfo( destination ).completeSuffix() );
106
107 const QgsVectorFileWriter::ActionOnExistingFile actionOnExistingFile = static_cast< QgsVectorFileWriter::ActionOnExistingFile >( parameterAsInt( parameters, QStringLiteral( "ACTION_ON_EXISTING_FILE" ), context ) );
108
109 QString finalFileName;
110 QString finalLayerName;
112 saveOptions.fileEncoding = context.defaultEncoding().isEmpty() ? QStringLiteral( "system" ) : context.defaultEncoding();
113 saveOptions.layerName = layerName;
114 saveOptions.driverName = format;
115 saveOptions.datasourceOptions = datasourceOptions;
116 saveOptions.layerOptions = layerOptions;
118 saveOptions.actionOnExistingFile = actionOnExistingFile;
119
120 std::unique_ptr< QgsVectorFileWriter > writer( QgsVectorFileWriter::create( destination, source->fields(), source->wkbType(), source->sourceCrs(), context.transformContext(), saveOptions, QgsFeatureSink::SinkFlags(), &finalFileName, &finalLayerName ) );
121 if ( writer->hasError() )
122 {
123 throw QgsProcessingException( QObject::tr( "Could not create layer %1: %2" ).arg( destination, writer->errorMessage() ) );
124 }
125
126 if ( QgsProcessingFeedback *feedback = context.feedback() )
127 {
128 for ( const QgsField &field : source->fields() )
129 {
130 if ( !field.alias().isEmpty() && !( writer->capabilities() & Qgis::VectorFileWriterCapability::FieldAliases ) )
131 feedback->pushWarning( QObject::tr( "%1: Aliases are not supported by %2" ).arg( field.name(), writer->driverLongName() ) );
132 if ( !field.alias().isEmpty() && !( writer->capabilities() & Qgis::VectorFileWriterCapability::FieldComments ) )
133 feedback->pushWarning( QObject::tr( "%1: Comments are not supported by %2" ).arg( field.name(), writer->driverLongName() ) );
134 }
135 }
136
137 destination = finalFileName;
138 if ( !saveOptions.layerName.isEmpty() && !finalLayerName.isEmpty() )
139 destination += QStringLiteral( "|layername=%1" ).arg( finalLayerName );
140
141 std::unique_ptr< QgsFeatureSink > sink( new QgsProcessingFeatureSink( writer.release(), destination, context, true ) );
142 if ( !sink )
143 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
144
145 const double step = source->featureCount() > 0 ? 100.0 / source->featureCount() : 1;
146 long long i = 0;
147
149 QgsFeature feat;
150 while ( features.nextFeature( feat ) )
151 {
152 i++;
153 if ( feedback->isCanceled() )
154 {
155 break;
156 }
157
158 feedback->setProgress( i * step );
159
160 if ( !sink->addFeature( feat, QgsFeatureSink::FastInsert ) )
161 throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
162 }
163
164 finalFileName = destination;
165 finalLayerName.clear(); // value of final layer name will be extracted from the destination string
166 const int separatorIndex = destination.indexOf( '|' );
167 if ( separatorIndex > -1 )
168 {
169 const thread_local QRegularExpression layerNameRx( QStringLiteral( "\\|layername=([^\\|]*)" ) );
170 const QRegularExpressionMatch match = layerNameRx.match( destination );
171 if ( match.hasMatch() )
172 {
173 finalLayerName = match.captured( 1 );
174 }
175 finalFileName = destination.mid( 0, separatorIndex );
176 }
177
178 QVariantMap outputs;
179 outputs.insert( QStringLiteral( "OUTPUT" ), destination );
180 outputs.insert( QStringLiteral( "FILE_PATH" ), finalFileName );
181 outputs.insert( QStringLiteral( "LAYER_NAME" ), finalLayerName );
182 return outputs;
183}
184
@ FieldComments
Writer can support field comments.
@ FieldAliases
Writer can support field aliases.
@ NoSymbology
Export only data.
Wrapper for iterator of features from vector data provider or vector layer.
bool nextFeature(QgsFeature &f)
This class wraps a request for features to a vector layer (or directly its vector data provider).
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:56
bool isCanceled() const
Tells whether the operation has been canceled already.
Definition qgsfeedback.h:54
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition qgsfeedback.h:63
Encapsulate a field in an attribute table or data source.
Definition qgsfield.h:53
Contains information about the context in which a processing algorithm is executed.
QString defaultEncoding() const
Returns the default encoding to use for newly created files.
QgsProcessingFeedback * feedback()
Returns the associated feedback object.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
Custom exception class for processing related exceptions.
QgsProxyFeatureSink subclass which reports feature addition errors to a QgsProcessingContext.
@ FlagSkipGeometryValidityChecks
Invalid geometry checks should always be skipped. This flag can be useful for algorithms which always...
Base class for providing feedback from a processing algorithm.
virtual void pushWarning(const QString &warning)
Pushes a warning informational message from the algorithm.
A string output for processing algorithms.
@ FlagAdvanced
Parameter is an advanced parameter which should be hidden from users by default.
An input feature source (such as vector layers) parameter for processing algorithms.
A generic file based destination parameter, for specifying the destination path for a file (non-map l...
@ TypeVector
Tables (i.e. vector layers with or without geometry). When used for a sink this indicates the sink ha...
Options to pass to writeAsVectorFormat()
QString layerName
Layer name. If let empty, it will be derived from the filename.
QStringList layerOptions
List of OGR layer creation options.
Qgis::FeatureSymbologyExport symbologyExport
Symbology to export.
QgsVectorFileWriter::ActionOnExistingFile actionOnExistingFile
Action on existing file.
QStringList datasourceOptions
List of OGR data source creation options.
static QString driverForExtension(const QString &extension)
Returns the OGR driver name for a specified file extension.
static QgsVectorFileWriter * create(const QString &fileName, const QgsFields &fields, Qgis::WkbType geometryType, const QgsCoordinateReferenceSystem &srs, const QgsCoordinateTransformContext &transformContext, const QgsVectorFileWriter::SaveVectorOptions &options, QgsFeatureSink::SinkFlags sinkFlags=QgsFeatureSink::SinkFlags(), QString *newFilename=nullptr, QString *newLayer=nullptr)
Create a new vector file writer.
static QString fileFilterString(VectorFormatOptions options=SortRecommended)
Returns filter string that can be used for dialogs.
ActionOnExistingFile
Combination of CanAddNewLayer, CanAppendToExistingLayer, CanAddNewFieldsToExistingLayer or CanDeleteL...