QGIS API Documentation 3.29.0-Master (19d7edcfed)
qgsserverfeatureid.cpp
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1/***************************************************************************
2 qgsserverfeatureid.cpp
3 -----------------------
4 begin : May 17, 2019
5 copyright : (C) 2019 by René-Luc DHONT
6 email : rldhont at 3liz 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
18#include "qgsserverfeatureid.h"
19#include "qgsfeature.h"
20#include "qgsfeaturerequest.h"
22#include "qgsexpression.h"
23
24QString QgsServerFeatureId::getServerFid( const QgsFeature &feature, const QgsAttributeList &pkAttributes )
25{
26 if ( pkAttributes.isEmpty() )
27 {
28 return QString::number( feature.id() );
29 }
30
31 QStringList pkValues;
32 for ( const auto &attrIdx : std::as_const( pkAttributes ) )
33 {
34 pkValues.append( feature.attribute( attrIdx ).toString() );
35 }
36 return pkValues.join( pkSeparator() );
37}
38
40{
41 const QgsAttributeList &pkAttributes = provider->pkAttributeIndexes();
42
43 if ( pkAttributes.isEmpty() )
44 {
45 QgsFeatureIds fids;
46 for ( const QString &serverFid : serverFids )
47 {
48 fids.insert( STRING_TO_FID( serverFid ) );
49 }
50 featureRequest.setFilterFids( fids );
51 return featureRequest;
52 }
53
54 QStringList expList;
55 for ( const QString &serverFid : serverFids )
56 {
57 expList.append( QgsServerFeatureId::getExpressionFromServerFid( serverFid, provider ) );
58 }
59
60 if ( expList.count() == 1 )
61 {
62 featureRequest.combineFilterExpression( expList.at( 0 ) );
63 }
64 else
65 {
66 QString fullExpression;
67 for ( const QString &exp : std::as_const( expList ) )
68 {
69 if ( !fullExpression.isEmpty() )
70 {
71 fullExpression.append( QStringLiteral( " OR " ) );
72 }
73 fullExpression.append( QStringLiteral( "( " ) );
74 fullExpression.append( exp );
75 fullExpression.append( QStringLiteral( " )" ) );
76 }
77 featureRequest.combineFilterExpression( fullExpression );
78 }
79
80 return featureRequest;
81}
82
83QString QgsServerFeatureId::getExpressionFromServerFid( const QString &serverFid, const QgsVectorDataProvider *provider )
84{
85 const QgsAttributeList &pkAttributes = provider->pkAttributeIndexes();
86
87 if ( pkAttributes.isEmpty() )
88 {
89 return QString();
90 }
91
92 const QgsFields &fields = provider->fields();
93
94 QString expressionString;
95 QStringList pkValues = serverFid.split( pkSeparator() );
96 int pkExprSize = std::min( pkAttributes.size(), pkValues.size() );
97 for ( int i = 0; i < pkExprSize; ++i )
98 {
99 if ( i > 0 )
100 {
101 expressionString.append( QStringLiteral( " AND " ) );
102 }
103
104 QString fieldName = fields[ pkAttributes.at( i ) ].name();
105 expressionString.append( QgsExpression::createFieldEqualityExpression( fieldName, QVariant( pkValues.at( i ) ) ) );
106 }
107
108 return expressionString;
109}
110
112{
113 return QStringLiteral( "@@" );
114}
static QString createFieldEqualityExpression(const QString &fieldName, const QVariant &value, QVariant::Type fieldType=QVariant::Type::Invalid)
Create an expression allowing to evaluate if a field is equal to a value.
This class wraps a request for features to a vector layer (or directly its vector data provider).
QgsFeatureRequest & combineFilterExpression(const QString &expression)
Modifies the existing filter expression to add an additional expression filter.
QgsFeatureRequest & setFilterFids(const QgsFeatureIds &fids)
Sets the feature IDs that should be fetched.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
QVariant attribute(const QString &name) const
Lookup attribute value by attribute name.
Definition: qgsfeature.cpp:338
Q_GADGET QgsFeatureId id
Definition: qgsfeature.h:64
Container of fields for a vector layer.
Definition: qgsfields.h:45
bool append(const QgsField &field, FieldOrigin origin=OriginProvider, int originIndex=-1)
Appends a field. The field must have unique name, otherwise it is rejected (returns false)
Definition: qgsfields.cpp:59
This is the base class for vector data providers.
virtual QgsAttributeList pkAttributeIndexes() const
Returns list of indexes of fields that make up the primary key.
QgsFields fields() const override=0
Returns the fields associated with this data provider.
SERVER_EXPORT QString getExpressionFromServerFid(const QString &serverFid, const QgsVectorDataProvider *provider)
Returns the expression feature id based on primary keys.
SERVER_EXPORT QString pkSeparator()
Returns the primary keys separator.
SERVER_EXPORT QgsFeatureRequest updateFeatureRequestFromServerFids(QgsFeatureRequest &featureRequest, const QStringList &serverFids, const QgsVectorDataProvider *provider)
Returns the feature request based on feature ids build with primary keys.
SERVER_EXPORT QString getServerFid(const QgsFeature &feature, const QgsAttributeList &pkAttributes)
Returns the feature id based on primary keys.
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeatureid.h:37
#define STRING_TO_FID(str)
Definition: qgsfeatureid.h:34
QList< int > QgsAttributeList
Definition: qgsfield.h:26