Add support for empty OGC WMS filters

The FILTER query parameter can now look like that: `(<Filter>...</Filter>)()` That means that the second layer has no filter. This is compliant with waht MapServer supports: https://mapserver.org/development/rfc/ms-rfc-118.html#examples
qgis · Sep 3, 2018 · da58c1d · da58c1d
1 parent 3f85938
commit da58c1d
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Showing 2 changed files with 60 additions and 22 deletions.
diff --git a/src/server/services/wms/qgswmsparameters.cpp b/src/server/services/wms/qgswmsparameters.cpp
@@ -1167,29 +1167,46 @@ namespace QgsWms
   QStringList QgsWmsParameters::filters() const
   {
     const QString filter = mWmsParameters[ QgsWmsParameter::FILTER ].toString();
-    if ( filter.startsWith( QStringLiteral( "(<" ) ) && filter.endsWith( QStringLiteral( "Filter>)" ) ) )
+    QStringList results;
+    int pos = 0;
+    while ( pos < filter.size() )
     {
-      // OGC filter on multiple layers
-      // remove the "(<" at the beginning and the "Filter>)" at the end
-      const QString toSplit = filter.mid( 2, filter.length() - 10 );
-
-      QStringList result;
-      for ( const QString &cur : toSplit.split( QStringLiteral( "Filter>)(<" ), QString::SkipEmptyParts ) )
+      if ( pos + 1 < filter.size() && filter[pos] == '(' && filter[pos + 1] == '<' )
       {
-        result.append( QStringLiteral( "<" ) + cur + QStringLiteral( "Filter>" ) );
+        // OGC filter on multiple layers
+        int posEnd = filter.indexOf( "Filter>)", pos );
+        if ( posEnd < 0 )
+        {
+          posEnd = filter.size();
+        }
+        results.append( filter.mid( pos + 1, posEnd - pos + 6 ) );
+        pos = posEnd + 8;
+      }
+      else if ( pos + 1 < filter.size() && filter[pos] == '(' && filter[pos + 1] == ')' )
+      {
+        // empty OGC filter
+        results.append( "" );
+        pos += 2;
+      }
+      else if ( filter[pos] == '<' )
+      {
+        // Single OGC filter
+        results.append( filter.mid( pos ) );
+        break;
+      }
+      else
+      {
+        // QGIS specific filter
+        int posEnd = filter.indexOf( ';', pos + 1 );
+        if ( posEnd < 0 )
+        {
+          posEnd = filter.size();
+        }
+        results.append( filter.mid( pos, posEnd - pos ) );
+        pos = posEnd + 1;
       }
-      return result;
-    }
-    else if ( filter.startsWith( QStringLiteral( "<" ) ) && filter.endsWith( QStringLiteral( "Filter>" ) ) )
-    {
-      // single OGC filter
-      return QStringList( filter );
-    }
-    else
-    {
-      // QGIS specific filter
-      return filter.split( ';', QString::SkipEmptyParts );
     }
+    return results;
   }
 
   QString QgsWmsParameters::filterGeom() const
@@ -1233,8 +1250,6 @@ namespace QgsWms
 
   QMultiMap<QString, QString> QgsWmsParameters::getLayerFilters( const QStringList &layers ) const
   {
-    // filter format: "LayerName:filterString;LayerName2:filterString2;..."
-    // several filters can be defined for one layer
     const QStringList rawFilters = filters();
     QMultiMap<QString, QString> layerFilters;
     for ( int i = 0; i < rawFilters.size(); i++ )
@@ -1244,8 +1259,10 @@ namespace QgsWms
       {
         layerFilters.insert( layers[i], f );
       }
-      else
+      else if ( !f.isEmpty() )
       {
+        // filter format: "LayerName:filterString;LayerName2:filterString2;..."
+        // several filters can be defined for one layer
         const QStringList splits = f.split( ':' );
         if ( splits.size() == 2 )
         {

diff --git a/tests/src/python/test_qgsserver_wms_getmap.py b/tests/src/python/test_qgsserver_wms_getmap.py
@@ -800,6 +800,27 @@ def test_wms_getmap_filter_ogc(self):
         r, h = self._result(self._execute_request(qs))
         self._img_diff_error(r, h, "WMS_GetMap_Filter_OGC")
 
+    def test_wms_getmap_filter_ogc_with_empty(self):
+        filter = "(<Filter><PropertyIsEqualTo><PropertyName>name</PropertyName>" + \
+                 "<Literal>eurasia</Literal></PropertyIsEqualTo></Filter>)()"
+        qs = "?" + "&".join(["%s=%s" % i for i in list({
+            "MAP": urllib.parse.quote(self.projectPath),
+            "SERVICE": "WMS",
+            "VERSION": "1.1.1",
+            "REQUEST": "GetMap",
+            "LAYERS": "Country,Hello",
+            "STYLES": "",
+            "FORMAT": "image/png",
+            "BBOX": "-16817707,-4710778,5696513,14587125",
+            "HEIGHT": "500",
+            "WIDTH": "500",
+            "CRS": "EPSG:3857",
+            "FILTER": filter
+        }.items())])
+
+        r, h = self._result(self._execute_request(qs))
+        self._img_diff_error(r, h, "WMS_GetMap_Filter_OGC")
+
     def test_wms_getmap_selection(self):
         qs = "?" + "&".join(["%s=%s" % i for i in list({
             "MAP": urllib.parse.quote(self.projectPath),