Helper utilities for working with JSON and GeoJSON conversions. More...

#include <qgsjsonutils.h>

Static Public Member Functions
static void	addCrsInfo (json &value, const QgsCoordinateReferenceSystem &crs)
	Add crs information entry in json object regarding old GeoJSON specification format if it differs from OGC:CRS84 or EPSG:4326.

static Q_INVOKABLE QString	encodeValue (const QVariant &value)
	Encodes a value to a JSON string representation, adding appropriate quotations and escaping where required.

static QString	exportAttributes (const QgsFeature &feature, QgsVectorLayer *layer=nullptr, const QVector< QVariant > &attributeWidgetCaches=QVector< QVariant >())
	Exports all attributes from a QgsFeature as a JSON map type.

static json	exportAttributesToJsonObject (const QgsFeature &feature, QgsVectorLayer *layer=nullptr, const QVector< QVariant > &attributeWidgetCaches=QVector< QVariant >())
	Exports all attributes from a QgsFeature as a json object.

static QgsGeometry	geometryFromGeoJson (const json &geometry)
	Parses a GeoJSON "geometry" value to a QgsGeometry object.

static QgsGeometry	geometryFromGeoJson (const QString &geometry)
	Parses a GeoJSON "geometry" value to a QgsGeometry object.

static json	jsonFromVariant (const QVariant &v)
	Converts a QVariant v to a json object.

static QVariant	jsonToVariant (const json &value)
	Converts a JSON value to a QVariant, in case of parsing error an invalid QVariant is returned.

static Q_INVOKABLE QVariantList	parseArray (const QString &json, QMetaType::Type type=QMetaType::Type::UnknownType)
	Parse a simple array (depth=1)

Q_INVOKABLE static Q_DECL_DEPRECATED QVariantList	parseArray (const QString &json, QVariant::Type type)
	Parse a simple array (depth=1)

static QVariant	parseJson (const QString &jsonString)
	Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned.

static QVariant	parseJson (const std::string &jsonString)
	Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned and an error is logged to the message log.

static QVariant	parseJson (const std::string &jsonString, QString &error)
	Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned and the error argument is populated accordingly.

static QgsFeatureList	stringToFeatureList (const QString &string, const QgsFields &fields=QgsFields(), QTextCodec *encoding SIP_PYARGREMOVE6=nullptr)
	Attempts to parse a GeoJSON string to a collection of features.

static QgsFields	stringToFields (const QString &string, QTextCodec *encoding SIP_PYARGREMOVE6=nullptr)
	Attempts to retrieve the fields from a GeoJSON string representing a collection of features.

Detailed Description

Helper utilities for working with JSON and GeoJSON conversions.

Definition at line 302 of file qgsjsonutils.h.

Member Function Documentation

◆ addCrsInfo()

void QgsJsonUtils::addCrsInfo	(	json &	value,
		const QgsCoordinateReferenceSystem &	crs
	)

static

Add crs information entry in json object regarding old GeoJSON specification format if it differs from OGC:CRS84 or EPSG:4326.

According to new specification RFC 7946, coordinate reference system for all GeoJSON coordinates is assumed to be OGC:CRS84 but when user specifically request a different CRS, this method adds this information in the JSON output

Definition at line 924 of file qgsjsonutils.cpp.

◆ encodeValue()

QString QgsJsonUtils::encodeValue ( const QVariant & value )

static

Encodes a value to a JSON string representation, adding appropriate quotations and escaping where required.

Parameters

value value to encode

Returns: encoded value

Definition at line 284 of file qgsjsonutils.cpp.

◆ exportAttributes()

QString QgsJsonUtils::exportAttributes	(	const QgsFeature &	feature,
		QgsVectorLayer *	layer = `nullptr`,
		const QVector< QVariant > &	attributeWidgetCaches = `QVector<QVariant>()`
	)

static

Exports all attributes from a QgsFeature as a JSON map type.

Parameters

feature	feature to export
layer	optional associated vector layer. If specified, this allows richer export utilising settings like the layer's fields widget configuration.
attributeWidgetCaches	optional widget configuration cache. Can be used to speed up exporting the attributes for multiple features from the same layer.

Definition at line 321 of file qgsjsonutils.cpp.

◆ exportAttributesToJsonObject()

json QgsJsonUtils::exportAttributesToJsonObject	(	const QgsFeature &	feature,
		QgsVectorLayer *	layer = `nullptr`,
		const QVector< QVariant > &	attributeWidgetCaches = `QVector<QVariant>()`
	)

static

Exports all attributes from a QgsFeature as a json object.

Parameters

feature	feature to export
layer	optional associated vector layer. If specified, this allows richer export utilising settings like the layer's fields widget configuration.
attributeWidgetCaches	optional widget configuration cache. Can be used to speed up exporting the attributes for multiple features from the same layer.

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 904 of file qgsjsonutils.cpp.

◆ geometryFromGeoJson() [1/2]

QgsGeometry QgsJsonUtils::geometryFromGeoJson ( const json & geometry )

static

Parses a GeoJSON "geometry" value to a QgsGeometry object.

Returns a null geometry if the geometry could not be parsed.

Note: Not available in Python bindings.

Since: QGIS 3.36

Definition at line 697 of file qgsjsonutils.cpp.

◆ geometryFromGeoJson() [2/2]

QgsGeometry QgsJsonUtils::geometryFromGeoJson ( const QString & geometry )

static

Parses a GeoJSON "geometry" value to a QgsGeometry object.

Returns a null geometry if the geometry could not be parsed.

Since: QGIS 3.36

Definition at line 708 of file qgsjsonutils.cpp.

◆ jsonFromVariant()

json QgsJsonUtils::jsonFromVariant ( const QVariant & v )

static

Converts a QVariant v to a json object.

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 722 of file qgsjsonutils.cpp.

◆ jsonToVariant()

QVariant QgsJsonUtils::jsonToVariant ( const json & value )

static

Converts a JSON value to a QVariant, in case of parsing error an invalid QVariant is returned.

Note: Not available in Python bindings

Since: QGIS 3.36

Definition at line 805 of file qgsjsonutils.cpp.

◆ parseArray() [1/2]

QVariantList QgsJsonUtils::parseArray	(	const QString &	json,
		QMetaType::Type	type = `QMetaType::Type::UnknownType`
	)

static

Parse a simple array (depth=1)

Parameters

json	the JSON to parse
type	optional variant type of the elements, if specified (and not Invalid), the array items will be converted to the type, and discarded if the conversion is not possible.

Definition at line 345 of file qgsjsonutils.cpp.

◆ parseArray() [2/2]

QVariantList QgsJsonUtils::parseArray	(	const QString &	json,
		QVariant::Type	type
	)

static

Parse a simple array (depth=1)

Parameters

json	the JSON to parse
type	optional variant type of the elements, if specified (and not Invalid), the array items will be converted to the type, and discarded if the conversion is not possible.

Deprecated:: since QGIS 3.38, use the method with a QMetaType::Type argument instead

Definition at line 414 of file qgsjsonutils.cpp.

◆ parseJson() [1/3]

QVariant QgsJsonUtils::parseJson ( const QString & jsonString )

static

Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned.

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 899 of file qgsjsonutils.cpp.

◆ parseJson() [2/3]

QVariant QgsJsonUtils::parseJson ( const std::string & jsonString )

static

Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned and an error is logged to the message log.

Note: Not available in Python bindings

Since: QGIS 3.8

Definition at line 777 of file qgsjsonutils.cpp.

◆ parseJson() [3/3]

QVariant QgsJsonUtils::parseJson	(	const std::string &	jsonString,
		QString &	error
	)

static

Converts JSON jsonString to a QVariant, in case of parsing error an invalid QVariant is returned and the error argument is populated accordingly.

Note: Not available in Python bindings

Since: QGIS 3.24

Definition at line 790 of file qgsjsonutils.cpp.

◆ stringToFeatureList()

QgsFeatureList QgsJsonUtils::stringToFeatureList	(	const QString &	string,
		const QgsFields &	fields = `QgsFields()`,
		QTextCodec *encoding	SIP_PYARGREMOVE6 = `nullptr`
	)

static

Attempts to parse a GeoJSON string to a collection of features.

It is possible to specify fields to parse specific fields, if not provided, no fields will be included. An encoding can be specified which defaults to UTF-8 if it is nullptr.

Returns: a list of parsed features, or an empty list if no features could be parsed

See also: stringToFields()

Note: this function is a wrapper around QgsOgrUtils::stringToFeatureList()

Definition at line 268 of file qgsjsonutils.cpp.

◆ stringToFields()

QgsFields QgsJsonUtils::stringToFields	(	const QString &	string,
		QTextCodec *encoding	SIP_PYARGREMOVE6 = `nullptr`
	)

static

Attempts to retrieve the fields from a GeoJSON string representing a collection of features.

An encoding can be specified which defaults to UTF-8 if it is nullptr.

Returns: retrieved fields collection, or an empty list if no fields could be determined from the string

See also: stringToFeatureList()

Note: this function is a wrapper around QgsOgrUtils::stringToFields()

Definition at line 276 of file qgsjsonutils.cpp.

The documentation for this class was generated from the following files:

/home/fischer/src/qgis-3.38/src/core/qgsjsonutils.h
/home/fischer/src/qgis-3.38/src/core/qgsjsonutils.cpp

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ addCrsInfo()

◆ encodeValue()

◆ exportAttributes()

◆ exportAttributesToJsonObject()

◆ geometryFromGeoJson() [1/2]

◆ geometryFromGeoJson() [2/2]

◆ jsonFromVariant()

◆ jsonToVariant()

◆ parseArray() [1/2]

◆ parseArray() [2/2]

◆ parseJson() [1/3]

◆ parseJson() [2/3]

◆ parseJson() [3/3]

◆ stringToFeatureList()

◆ stringToFields()