Write entry to server log if a datasource/map/print composition is no…

…t valid

src/server/qgsconfigcache.cpp

@@ -48,6 +48,8 @@ const QgsProject *QgsConfigCache::project( const QString &path )
     {
       if ( badLayerHandler->badLayers().size() > 0 )
       {
+        QString errorMsg = QString( "Layer(s) %1 not valid" ).arg( badLayerHandler->badLayers().join( ',' ) );
+        QgsMessageLog::logMessage( errorMsg, QStringLiteral( "Server" ), Qgis::Critical );
         throw QgsServerException( QStringLiteral( "Layer(s) not valid" ) );
       }
       mProjectCache.insert( path, prj.release() );

src/server/qgsfcgiserverrequest.cpp

@@ -68,7 +68,7 @@ QgsFcgiServerRequest::QgsFcgiServerRequest()
   }
 
   // Store the URL before the server rewrite that could have been set in QUERY_STRING
-  //mOriginalUrl = url;
+  mOriginalUrl = url;
 
   // OGC parameters are passed with the query string, which is normally part of
   // the REQUEST_URI, we override the query string url in case it is defined

src/server/services/wms/qgswmsrenderer.cpp

@@ -2930,11 +2930,16 @@ namespace QgsWms
       if ( !renderJob.errors().isEmpty() )
       {
         QString layerWMSName;
-        QgsMapLayer *errorLayer = mProject->mapLayer( renderJob.errors().at( 0 ).layerID );
+        QString firstErrorLayerId = renderJob.errors().at( 0 ).layerID;
+        QgsMapLayer *errorLayer = mProject->mapLayer( firstErrorLayerId );
         if ( errorLayer )
         {
           layerWMSName = layerNickname( *errorLayer );
         }
+
+        //Log first error
+        QString errorMsg = QString( "Map rendering error in layer '%1'" ).arg( firstErrorLayerId );
+        QgsMessageLog::logMessage( errorMsg, "Server", Qgis::Critical );
         throw QgsServerException( QString( "Map rendering error in layer '%1'" ).arg( layerWMSName ) );
       }
     }
@@ -3274,6 +3279,11 @@ namespace QgsWms
     {
       if ( !( *mapIt )->renderingErrors().isEmpty() )
       {
+        //Log first error
+        QgsMapRendererJob::Error e = ( *mapIt )->renderingErrors().at( 0 );
+        QString errorMsg = QString( "Rendering error : '%1' in layer %2" ).arg( e.message ).arg( e.layerID );
+        QgsMessageLog::logMessage( errorMsg, "Server", Qgis::Critical );
+
         throw QgsServerException( QStringLiteral( "Print error" ) );
       }
     }