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       1                 :            : /***************************************************************************
       2                 :            :     qgsjsonutils.h
       3                 :            :      -------------
       4                 :            :     Date                 : May 206
       5                 :            :     Copyright            : (C) 2016 Nyall Dawson
       6                 :            :     Email                : nyall dot dawson at gmail dot com
       7                 :            :  ***************************************************************************
       8                 :            :  *                                                                         *
       9                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      10                 :            :  *   it under the terms of the GNU General Public License as published by  *
      11                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      12                 :            :  *   (at your option) any later version.                                   *
      13                 :            :  *                                                                         *
      14                 :            :  ***************************************************************************/
      15                 :            : 
      16                 :            : #ifndef QGSJSONUTILS_H
      17                 :            : #define QGSJSONUTILS_H
      18                 :            : 
      19                 :            : #include "qgis_core.h"
      20                 :            : #include "qgsfeature.h"
      21                 :            : #include "qgscoordinatereferencesystem.h"
      22                 :            : #include "qgscoordinatetransform.h"
      23                 :            : #include "qgsfields.h"
      24                 :            : 
      25                 :            : #ifndef SIP_RUN
      26                 :            : #include <json_fwd.hpp>
      27                 :            : using namespace nlohmann;
      28                 :            : #endif
      29                 :            : 
      30                 :            : #include <QPointer>
      31                 :            : #include <QJsonObject>
      32                 :            : 
      33                 :            : class QTextCodec;
      34                 :            : 
      35                 :            : /**
      36                 :            :  * \ingroup core
      37                 :            :  * \class QgsJsonExporter
      38                 :            :  * \brief Handles exporting QgsFeature features to GeoJSON features.
      39                 :            :  *
      40                 :            :  * Note that geometries will be automatically reprojected to WGS84 to match GeoJSON spec
      41                 :            :  * if either the source vector layer or source CRS is set.
      42                 :            :  * \since QGIS 2.16
      43                 :            :  */
      44                 :            : 
      45                 :          0 : class CORE_EXPORT QgsJsonExporter
      46                 :            : {
      47                 :            :   public:
      48                 :            : 
      49                 :            :     /**
      50                 :            :      * Constructor for QgsJsonExporter.
      51                 :            :      * \param vectorLayer associated vector layer (required for related attribute export)
      52                 :            :      * \param precision maximum number of decimal places to use for geometry coordinates,
      53                 :            :      *  the RFC 7946 GeoJSON specification recommends limiting coordinate precision to 6
      54                 :            :      */
      55                 :            :     QgsJsonExporter( QgsVectorLayer *vectorLayer = nullptr, int precision = 6 );
      56                 :            : 
      57                 :            :     /**
      58                 :            :      * Sets the maximum number of decimal places to use in geometry coordinates.
      59                 :            :      * The RFC 7946 GeoJSON specification recommends limiting coordinate precision to 6
      60                 :            :      * \param precision number of decimal places
      61                 :            :      * \see precision()
      62                 :            :      */
      63                 :            :     void setPrecision( int precision ) { mPrecision = precision; }
      64                 :            : 
      65                 :            :     /**
      66                 :            :      * Returns the maximum number of decimal places to use in geometry coordinates.
      67                 :            :      * \see setPrecision()
      68                 :            :      */
      69                 :            :     int precision() const { return mPrecision; }
      70                 :            : 
      71                 :            :     /**
      72                 :            :      * Sets whether to include geometry in the JSON exports.
      73                 :            :      * \param includeGeometry set to FALSE to prevent geometry inclusion
      74                 :            :      * \see includeGeometry()
      75                 :            :      */
      76                 :            :     void setIncludeGeometry( bool includeGeometry ) { mIncludeGeometry = includeGeometry; }
      77                 :            : 
      78                 :            :     /**
      79                 :            :      * Returns whether geometry will be included in the JSON exports.
      80                 :            :      * \see setIncludeGeometry()
      81                 :            :      */
      82                 :            :     bool includeGeometry() const { return mIncludeGeometry; }
      83                 :            : 
      84                 :            :     /**
      85                 :            :      * Sets whether to include attributes in the JSON exports.
      86                 :            :      * \param includeAttributes set to FALSE to prevent attribute inclusion
      87                 :            :      * \see includeAttributes()
      88                 :            :      */
      89                 :            :     void setIncludeAttributes( bool includeAttributes ) { mIncludeAttributes = includeAttributes; }
      90                 :            : 
      91                 :            :     /**
      92                 :            :      * Returns whether attributes will be included in the JSON exports.
      93                 :            :      * \see setIncludeAttributes()
      94                 :            :      */
      95                 :            :     bool includeAttributes() const { return mIncludeAttributes; }
      96                 :            : 
      97                 :            :     /**
      98                 :            :      * Sets whether to include attributes of features linked via references in the JSON exports.
      99                 :            :      * \param includeRelated set to TRUE to include attributes for any related child features
     100                 :            :      * within the exported properties element.
     101                 :            :      * \note associated vector layer must be set with setVectorLayer()
     102                 :            :      * \see includeRelated()
     103                 :            :      */
     104                 :          0 :     void setIncludeRelated( bool includeRelated ) { mIncludeRelatedAttributes = includeRelated; }
     105                 :            : 
     106                 :            :     /**
     107                 :            :      * Returns whether attributes of related (child) features will be included in the JSON exports.
     108                 :            :      * \see setIncludeRelated()
     109                 :            :      */
     110                 :            :     bool includeRelated() const { return mIncludeRelatedAttributes; }
     111                 :            : 
     112                 :            :     /**
     113                 :            :      * Sets whether to print original names of attributes or aliases if
     114                 :            :      * defined.
     115                 :            :      * \since QGIS 3.6
     116                 :            :      */
     117                 :            :     void setAttributeDisplayName( bool displayName ) { mAttributeDisplayName = displayName; }
     118                 :            : 
     119                 :            :     /**
     120                 :            :      * Returns whether original names of attributes or aliases are printed.
     121                 :            :      * \since QGIS 3.6
     122                 :            :      */
     123                 :            : 
     124                 :            :     bool attributeDisplayName() const { return mAttributeDisplayName; }
     125                 :            : 
     126                 :            :     /**
     127                 :            :      * Sets the associated vector layer (required for related attribute export). This will automatically
     128                 :            :      * update the sourceCrs() to match.
     129                 :            :      * \param vectorLayer vector layer
     130                 :            :      * \see vectorLayer()
     131                 :            :      */
     132                 :            :     void setVectorLayer( QgsVectorLayer *vectorLayer );
     133                 :            : 
     134                 :            :     /**
     135                 :            :      * Returns the associated vector layer, if set.
     136                 :            :      * \see setVectorLayer()
     137                 :            :      */
     138                 :            :     QgsVectorLayer *vectorLayer() const;
     139                 :            : 
     140                 :            :     /**
     141                 :            :      * Sets the source CRS for feature geometries. The source CRS must be set if geometries are to be
     142                 :            :      * correctly automatically reprojected to WGS 84, to match GeoJSON specifications.
     143                 :            :      * \param crs source CRS for input feature geometries
     144                 :            :      * \note the source CRS will be overwritten when a vector layer is specified via setVectorLayer()
     145                 :            :      * \see sourceCrs()
     146                 :            :      */
     147                 :            :     void setSourceCrs( const QgsCoordinateReferenceSystem &crs );
     148                 :            : 
     149                 :            :     /**
     150                 :            :      * Returns the source CRS for feature geometries. The source CRS must be set if geometries are to be
     151                 :            :      * correctly automatically reprojected to WGS 84, to match GeoJSON specifications.
     152                 :            :      * \see setSourceCrs()
     153                 :            :      */
     154                 :            :     QgsCoordinateReferenceSystem sourceCrs() const;
     155                 :            : 
     156                 :            :     /**
     157                 :            :      * Sets whether geometries should be transformed in EPSG 4326 (default
     158                 :            :      * behavior) or just keep as it is.
     159                 :            :      * \since QGIS 3.12
     160                 :            :      */
     161                 :            :     void setTransformGeometries( bool activate ) { mTransformGeometries = activate; }
     162                 :            : 
     163                 :            :     /**
     164                 :            :      * Sets the list of attributes to include in the JSON exports.
     165                 :            :      * \param attributes list of attribute indexes, or an empty list to include all
     166                 :            :      * attributes
     167                 :            :      * \see attributes()
     168                 :            :      * \see setExcludedAttributes()
     169                 :            :      * \note Attributes excluded via setExcludedAttributes() take precedence over
     170                 :            :      * attributes specified by this method.
     171                 :            :      */
     172                 :            :     void setAttributes( const QgsAttributeList &attributes ) { mAttributeIndexes = attributes; }
     173                 :            : 
     174                 :            :     /**
     175                 :            :      * Returns the list of attributes which will be included in the JSON exports, or
     176                 :            :      * an empty list if all attributes will be included.
     177                 :            :      * \see setAttributes()
     178                 :            :      * \see excludedAttributes()
     179                 :            :      * \note Attributes excluded via excludedAttributes() take precedence over
     180                 :            :      * attributes returned by this method.
     181                 :            :      */
     182                 :            :     QgsAttributeList attributes() const { return mAttributeIndexes; }
     183                 :            : 
     184                 :            :     /**
     185                 :            :      * Sets a list of attributes to specifically exclude from the JSON exports. Excluded attributes
     186                 :            :      * take precedence over attributes included via setAttributes().
     187                 :            :      * \param attributes list of attribute indexes to exclude
     188                 :            :      * \see excludedAttributes()
     189                 :            :      * \see setAttributes()
     190                 :            :      */
     191                 :            :     void setExcludedAttributes( const QgsAttributeList &attributes ) { mExcludedAttributeIndexes = attributes; }
     192                 :            : 
     193                 :            :     /**
     194                 :            :      * Returns a list of attributes which will be specifically excluded from the JSON exports. Excluded attributes
     195                 :            :      * take precedence over attributes included via attributes().
     196                 :            :      * \see setExcludedAttributes()
     197                 :            :      * \see attributes()
     198                 :            :      */
     199                 :            :     QgsAttributeList excludedAttributes() const { return mExcludedAttributeIndexes; }
     200                 :            : 
     201                 :            :     /**
     202                 :            :      * Returns a GeoJSON string representation of a feature.
     203                 :            :      * \param feature feature to convert
     204                 :            :      * \param extraProperties map of extra attributes to include in feature's properties
     205                 :            :      * \param id optional ID to use as GeoJSON feature's ID instead of input feature's ID. If omitted, feature's
     206                 :            :      * ID is used.
     207                 :            :      * \param indent number of indentation spaces for generated JSON (defaults to none)
     208                 :            :      * \returns GeoJSON string
     209                 :            :      * \see exportFeatures()
     210                 :            :      * \see exportFeatureToJsonObject()
     211                 :            :      */
     212                 :            :     QString exportFeature( const QgsFeature &feature,
     213                 :            :                            const QVariantMap &extraProperties = QVariantMap(),
     214                 :            :                            const QVariant &id = QVariant(),
     215                 :            :                            int indent = -1 ) const;
     216                 :            : 
     217                 :            :     /**
     218                 :            :      * Returns a QJsonObject representation of a feature.
     219                 :            :      * \param feature feature to convert
     220                 :            :      * \param extraProperties map of extra attributes to include in feature's properties
     221                 :            :      * \param id optional ID to use as GeoJSON feature's ID instead of input feature's ID. If omitted, feature's
     222                 :            :      * ID is used.
     223                 :            :      * \returns json object
     224                 :            :      * \see exportFeatures()
     225                 :            :      */
     226                 :            :     json exportFeatureToJsonObject( const QgsFeature &feature,
     227                 :            :                                     const QVariantMap &extraProperties = QVariantMap(),
     228                 :            :                                     const QVariant &id = QVariant() ) const SIP_SKIP;
     229                 :            : 
     230                 :            : 
     231                 :            :     /**
     232                 :            :      * Returns a GeoJSON string representation of a list of features (feature collection).
     233                 :            :      * \param features features to convert
     234                 :            :      * \param indent number of indentation spaces for generated JSON (defaults to none)
     235                 :            :      * \returns GeoJSON string
     236                 :            :      * \see exportFeature()
     237                 :            :      */
     238                 :            :     QString exportFeatures( const QgsFeatureList &features, int indent = -1 ) const;
     239                 :            : 
     240                 :            :     /**
     241                 :            :      * Returns a JSON object representation of a list of features (feature collection).
     242                 :            :      * \param features features to convert
     243                 :            :      * \returns json object
     244                 :            :      * \see exportFeatures()
     245                 :            :      * \since QGIS 3.10
     246                 :            :      */
     247                 :            :     json exportFeaturesToJsonObject( const QgsFeatureList &features ) const SIP_SKIP;
     248                 :            : 
     249                 :            :   private:
     250                 :            : 
     251                 :            :     //! Maximum number of decimal places for geometry coordinates
     252                 :            :     int mPrecision;
     253                 :            : 
     254                 :            :     /**
     255                 :            :      * List of attribute indexes to include in export, or empty list to include all attributes
     256                 :            :      * \see mExcludedAttributeIndexes
     257                 :            :      */
     258                 :            :     QgsAttributeList mAttributeIndexes;
     259                 :            : 
     260                 :            :     //! List of attribute indexes to exclude from export
     261                 :            :     QgsAttributeList mExcludedAttributeIndexes;
     262                 :            : 
     263                 :            :     //! Whether to include geometry in JSON export
     264                 :            :     bool mIncludeGeometry = true;
     265                 :            : 
     266                 :            :     //! Whether to include attributes in JSON export
     267                 :            :     bool mIncludeAttributes = true;
     268                 :            : 
     269                 :            :     //! Whether to include attributes from related features in JSON export
     270                 :            :     bool mIncludeRelatedAttributes = false;
     271                 :            : 
     272                 :            :     //! Associated vector layer. Required for related attribute export.
     273                 :            :     QPointer< QgsVectorLayer > mLayer;
     274                 :            : 
     275                 :            :     QgsCoordinateReferenceSystem mCrs;
     276                 :            : 
     277                 :            :     QgsCoordinateTransform mTransform;
     278                 :            : 
     279                 :            :     bool mAttributeDisplayName = false;
     280                 :            : 
     281                 :            :     bool mTransformGeometries = true;
     282                 :            : };
     283                 :            : 
     284                 :            : /**
     285                 :            :  * \ingroup core
     286                 :            :  * \class QgsJsonUtils
     287                 :            :  * \brief Helper utilities for working with JSON and GeoJSON conversions.
     288                 :            :  * \since QGIS 2.16
     289                 :            :  */
     290                 :            : 
     291                 :            : class CORE_EXPORT QgsJsonUtils
     292                 :            : {
     293                 :            :   public:
     294                 :            : 
     295                 :            :     /**
     296                 :            :      * Attempts to parse a GeoJSON \a string to a collection of features.
     297                 :            :      * It is possible to specify \a fields to parse specific fields, if not provided, no fields will be included.
     298                 :            :      * An \a encoding can be specified which defaults to UTF-8 if it is `nullptr`.
     299                 :            :      * \returns a list of parsed features, or an empty list if no features could be parsed
     300                 :            :      * \see stringToFields()
     301                 :            :      * \note this function is a wrapper around QgsOgrUtils::stringToFeatureList()
     302                 :            :      */
     303                 :            :     static QgsFeatureList stringToFeatureList( const QString &string, const QgsFields &fields = QgsFields(), QTextCodec *encoding = nullptr );
     304                 :            : 
     305                 :            :     /**
     306                 :            :      * Attempts to retrieve the fields from a GeoJSON  \a string representing a collection of features.
     307                 :            :      * An \a encoding can be specified which defaults to UTF-8 if it is `nullptr`.
     308                 :            :      * \returns retrieved fields collection, or an empty list if no fields could be determined from the string
     309                 :            :      * \see stringToFeatureList()
     310                 :            :      * \note this function is a wrapper around QgsOgrUtils::stringToFields()
     311                 :            :      */
     312                 :            :     static QgsFields stringToFields( const QString &string, QTextCodec *encoding = nullptr );
     313                 :            : 
     314                 :            :     /**
     315                 :            :      * Encodes a value to a JSON string representation, adding appropriate quotations and escaping
     316                 :            :      * where required.
     317                 :            :      * \param value value to encode
     318                 :            :      * \returns encoded value
     319                 :            :      */
     320                 :            :     static QString encodeValue( const QVariant &value );
     321                 :            : 
     322                 :            :     /**
     323                 :            :      * Exports all attributes from a QgsFeature as a JSON map type.
     324                 :            :      * \param feature feature to export
     325                 :            :      * \param layer optional associated vector layer. If specified, this allows
     326                 :            :      * richer export utilising settings like the layer's fields widget configuration.
     327                 :            :      * \param attributeWidgetCaches optional widget configuration cache. Can be used
     328                 :            :      * to speed up exporting the attributes for multiple features from the same layer.
     329                 :            :      */
     330                 :            :     static QString exportAttributes( const QgsFeature &feature, QgsVectorLayer *layer = nullptr,
     331                 :            :                                      const QVector<QVariant> &attributeWidgetCaches = QVector<QVariant>() );
     332                 :            : 
     333                 :            :     /**
     334                 :            :      * Exports all attributes from a QgsFeature as a json object.
     335                 :            :      * \param feature feature to export
     336                 :            :      * \param layer optional associated vector layer. If specified, this allows
     337                 :            :      * richer export utilising settings like the layer's fields widget configuration.
     338                 :            :      * \param attributeWidgetCaches optional widget configuration cache. Can be used
     339                 :            :      * to speed up exporting the attributes for multiple features from the same layer.
     340                 :            :      * \note Not available in Python bindings
     341                 :            :      * \since QGIS 3.8
     342                 :            :      */
     343                 :            :     static json exportAttributesToJsonObject( const QgsFeature &feature, QgsVectorLayer *layer = nullptr,
     344                 :            :         const QVector<QVariant> &attributeWidgetCaches = QVector<QVariant>() ) SIP_SKIP;
     345                 :            : 
     346                 :            :     /**
     347                 :            :      * Parse a simple array (depth=1)
     348                 :            :      * \param json the JSON to parse
     349                 :            :      * \param type optional variant type of the elements, if specified (and not Invalid),
     350                 :            :      *        the array items will be converted to the type, and discarded if
     351                 :            :      *        the conversion is not possible.
     352                 :            :      * \since QGIS 3.0
     353                 :            :      */
     354                 :            :     static QVariantList parseArray( const QString &json, QVariant::Type type = QVariant::Invalid );
     355                 :            : 
     356                 :            : 
     357                 :            :     /**
     358                 :            :      * Converts a QVariant \a v to a json object
     359                 :            :      * \note Not available in Python bindings
     360                 :            :      * \since QGIS 3.8
     361                 :            :      */
     362                 :            :     static json jsonFromVariant( const QVariant &v ) SIP_SKIP;
     363                 :            : 
     364                 :            :     /**
     365                 :            :      * Converts JSON \a jsonString to a QVariant, in case of parsing error an invalid QVariant is returned.
     366                 :            :      * \note Not available in Python bindings
     367                 :            :      * \since QGIS 3.8
     368                 :            :      */
     369                 :            :     static QVariant parseJson( const std::string &jsonString ) SIP_SKIP;
     370                 :            : 
     371                 :            :     /**
     372                 :            :      * Converts JSON \a jsonString to a QVariant, in case of parsing error an invalid QVariant is returned.
     373                 :            :      * \note Not available in Python bindings
     374                 :            :      * \since QGIS 3.8
     375                 :            :      */
     376                 :            :     static QVariant parseJson( const QString &jsonString ) SIP_SKIP;
     377                 :            : 
     378                 :            : };
     379                 :            : 
     380                 :            : #endif // QGSJSONUTILS_H