[FEATURE][QGIS Server] STARTINDEX param in WFS GetFeature Request

STARTINDEX is standard in WFS 2.0, but it's an extension for WFS 1.0 implemented in QGIS Server. STARTINDEX can be used to skip some features in the result set and in combination with MAXFEATURES provides for the ability to use WFS GetFeature to page through results. Note that STARTINDEX=0 means start with the first feature, skipping none.
qgis · Dec 14, 2015 · 30b3b68 · 30b3b68 · nyalldawson · Dec 15, 2015
1 parent cf60ddb
commit 30b3b68
Showing 1 changed file with 67 additions and 30 deletions.
diff --git a/src/server/qgswfsserver.cpp b/src/server/qgswfsserver.cpp
@@ -411,6 +411,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
 
   long maxFeat = 0;
   long maxFeatures = -1;
+  long startIndex = 0;
   long featureCounter = 0;
   int layerPrec = 8;
 
@@ -426,6 +427,8 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
 
     if ( docElem.hasAttribute( "maxFeatures" ) )
       maxFeatures = docElem.attribute( "maxFeatures" ).toLong();
+    if ( docElem.hasAttribute( "startIndex" ) )
+      startIndex = docElem.attribute( "startIndex" ).toLong();
 
     QDomNodeList queryNodes = docElem.elementsByTagName( "Query" );
     QDomElement queryElem;
@@ -624,13 +627,16 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
             req.setSubsetOfAttributes( attrIndexes );
 
             QgsFeatureIterator fit = layer->getFeatures( req );
-            while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+            while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
             {
-              if ( featureCounter == 0 )
+              if ( featureCounter == startIndex )
                 startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-              setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+              if ( featureCounter >= startIndex )
-              ++featCounter;
+              {
+                setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                ++featCounter;
+              }
               ++featureCounter;
             }
           }
@@ -643,7 +649,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
               {
                 throw QgsMapServiceException( "RequestNotWellFormed", filter->parserErrorString() );
               }
-              while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+              while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
               {
                 expressionContext.setFeature( feature );
 
@@ -654,26 +660,32 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
                 }
                 if ( res.toInt() != 0 )
                 {
-                  if ( featureCounter == 0 )
+                  if ( featureCounter == startIndex )
                     startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-                  setGetFeature( request, format, &feature, featureCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                  if ( featureCounter >= startIndex )
+                  {
+                    setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                    ++featCounter;
+                  }
                   ++featureCounter;
-                  ++featCounter;
                 }
               }
             }
           }
         }
         else
         {
-          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
           {
-            if ( featureCounter == 0 )
+            if ( featureCounter == startIndex )
               startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-            setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+            if ( featureCounter >= startIndex )
-            ++featCounter;
+            {
+              setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+              ++featCounter;
+            }
             ++featureCounter;
           }
         }
@@ -692,7 +704,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
     QgsMessageLog::logMessage( mErrors.join( "\n" ) );
 
     QgsMapLayerRegistry::instance()->removeAllMapLayers();
-    if ( featureCounter == 0 )
+    if ( featureCounter <= startIndex )
       startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
     endGetFeature( request, format );
     return 0;
@@ -806,6 +818,15 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
     maxFeat = mfString.toLong( &mfOk, 10 );
   }
 
+  //read STARTINDEX
+  QMap<QString, QString>::const_iterator siIt = mParameters.find( "STARTINDEX" );
+  if ( siIt != mParameters.end() )
+  {
+    QString siString = siIt.value();
+    bool siOk;
+    startIndex = siString.toLong( &siOk, 10 );
+  }
+
   //read PROPERTYNAME
   mWithGeom = true;
   mPropertyName = "*";
@@ -959,7 +980,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
           {
             throw QgsMapServiceException( "RequestNotWellFormed", QString( "Expression filter error message: %1." ).arg( filter->parserErrorString() ) );
           }
-          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
           {
             expressionContext.setFeature( feature );
             QVariant res = filter->evaluate( &expressionContext );
@@ -969,11 +990,14 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
             }
             if ( res.toInt() != 0 )
             {
-              if ( featureCounter == 0 )
+              if ( featureCounter == startIndex )
                 startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-              setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+              if ( featureCounter >= startIndex )
-              ++featCounter;
+              {
+                setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                ++featCounter;
+              }
               ++featureCounter;
             }
           }
@@ -1040,13 +1064,16 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
           req.setSubsetOfAttributes( attrIndexes );
 
           QgsFeatureIterator fit = layer->getFeatures( req );
-          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+          while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
           {
-            if ( featureCounter == 0 )
+            if ( featureCounter == startIndex )
               startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-            setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+            if ( featureCounter >= startIndex )
-            ++featCounter;
+            {
+              setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+              ++featCounter;
+            }
             ++featureCounter;
           }
         }
@@ -1078,7 +1105,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
             }
             req.setSubsetOfAttributes( attrIndexes );
             QgsFeatureIterator fit = layer->getFeatures( req );
-            while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+            while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
             {
               expressionContext.setFeature( feature );
               QVariant res = filter->evaluate( &expressionContext );
@@ -1088,12 +1115,15 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
               }
               if ( res.toInt() != 0 )
               {
-                if ( featureCounter == 0 )
+                if ( featureCounter == startIndex )
                   startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-                setGetFeature( request, format, &feature, featureCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                if ( featureCounter >= startIndex )
+                {
+                  setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+                  ++featCounter;
+                }
                 ++featureCounter;
-                ++featCounter;
               }
             }
           }
@@ -1121,14 +1151,17 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
         }
         req.setSubsetOfAttributes( attrIndexes );
         QgsFeatureIterator fit = layer->getFeatures( req );
-        while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat ) )
+        while ( fit.nextFeature( feature ) && ( maxFeatures == -1 || featureCounter < maxFeat + startIndex ) )
         {
           mErrors << QString( "The feature %2 of layer for the TypeName '%1'" ).arg( tnStr ).arg( featureCounter );
-          if ( featureCounter == 0 )
+          if ( featureCounter == startIndex )
             startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
 
-          setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+          if ( featureCounter >= startIndex )
-          ++featCounter;
+          {
+            setGetFeature( request, format, &feature, featCounter, layerPrec, layerCrs, attrIndexes, layerExcludedAttributes );
+            ++featCounter;
+          }
           ++featureCounter;
         }
       }
@@ -1142,7 +1175,7 @@ int QgsWFSServer::getFeature( QgsRequestHandler& request, const QString& format
   }
 
   QgsMapLayerRegistry::instance()->removeAllMapLayers();
-  if ( featureCounter == 0 )
+  if ( featureCounter <= startIndex )
     startGetFeature( request, format, layerPrec, layerCrs, &searchRect );
   endGetFeature( request, format );
 
@@ -1217,6 +1250,10 @@ void QgsWFSServer::startGetFeature( QgsRequestHandler& request, const QString& f
       {
         mapUrl.removeQueryItem( queryIt->first );
       }
+      else if ( queryIt->first.compare( "STARTINDEX", Qt::CaseInsensitive ) == 0 )
+      {
+        mapUrl.removeQueryItem( queryIt->first );
+      }
       else if ( queryIt->first.compare( "PROPERTYNAME", Qt::CaseInsensitive ) == 0 )
       {
         mapUrl.removeQueryItem( queryIt->first );