[FEATURE]: set default datumstransformation for server with environment variable

Author: mhugent

src/core/qgsmaprenderer.cpp

@@ -61,6 +61,7 @@ QgsMapRenderer::QgsMapRenderer()
   mFullExtent.setMinimal();
 
   mLabelingEngine = nullptr;
+  readDefaultDatumTransformations();
 }
 
 QgsMapRenderer::~QgsMapRenderer()
@@ -1110,6 +1111,12 @@ const QgsCoordinateTransform *QgsMapRenderer::transformation( const QgsMapLayer
   }
   else
   {
+    //is there a defined datum transformation?
+    QHash< QPair< QString, QString >, QPair< int, int > >::const_iterator it = mDefaultDatumTransformations.find( qMakePair( layer->crs().authid(), mDestCRS->authid() ) );
+    if ( it != mDefaultDatumTransformations.constEnd() )
+    {
+      return QgsCoordinateTransformCache::instance()->transform( it.key().first, it.key().second, it.value().first, it.value().second );
+    }
     emit datumTransformInfoRequested( layer, layer->crs().authid(), mDestCRS->authid() );
   }
 
@@ -1275,4 +1282,24 @@ void QgsMapRenderer::clearLayerCoordinateTransforms()
   mLayerCoordinateTransformInfo.clear();
 }
 
+void QgsMapRenderer::readDefaultDatumTransformations()
+{
+  const char* envChar = getenv( "DEFAULT_DATUM_TRANSFORM" );
+  if ( envChar )
+  {
+    QString envString( envChar );
+    QStringList transformSplit = envString.split( ";" );
+    for ( int i = 0; i < transformSplit.size(); ++i )
+    {
+      QStringList slashSplit = transformSplit.at( i ).split( "/" );
+      if ( slashSplit.size() < 4 )
+      {
+        continue;
+      }
+
+      mDefaultDatumTransformations.insert( qMakePair( slashSplit.at( 0 ), slashSplit.at( 1 ) ), qMakePair( slashSplit.at( 2 ).toInt(), slashSplit.at( 3 ).toInt() ) );
+    }
+  }
+}
+
 bool QgsMapRenderer::mDrawing = false;

src/core/qgsmaprenderer.h

@@ -456,6 +456,11 @@ class CORE_EXPORT QgsMapRenderer : public QObject
     QgsMapSettings mMapSettings;
 
     QHash< QString, QgsLayerCoordinateTransform > mLayerCoordinateTransformInfo;
+
+    QHash< QPair< QString, QString >, QPair< int, int > > mDefaultDatumTransformations;
+
+  private:
+    void readDefaultDatumTransformations();
 };
 
 #endif

src/server/qgsserver.cpp

@@ -78,12 +78,14 @@ bool QgsServer::sCaptureOutput = false;
 QgsServer::QgsServer( int &argc, char **argv )
 {
   init( argc, argv );
+  saveEnvVars();
 }
 
 
 QgsServer::QgsServer()
 {
   init();
+  saveEnvVars();
 }
 
 
@@ -454,6 +456,12 @@ void QgsServer::putenv( const QString &var, const QString &val )
  */
 QPair<QByteArray, QByteArray> QgsServer::handleRequest( const QString& queryString )
 {
+  //apply environment variables
+  QHash< QString, QString >::const_iterator envIt = mEnvironmentVariables.constBegin();
+  for ( ; envIt != mEnvironmentVariables.constEnd(); ++envIt )
+  {
+    putenv( envIt.key(), envIt.value() );
+  }
 
   /*
    * This is mainly for python bindings, passing QUERY_STRING
@@ -657,3 +665,20 @@ QPair<QByteArray, QByteArray> QgsServer::testQPair( QPair<QByteArray, QByteArray
 }
 #endif
 
+void QgsServer::saveEnvVars()
+{
+  saveEnvVar( "MAX_CACHE_LAYERS" );
+  saveEnvVar( "DEFAULT_DATUM_TRANSFORM" );
+}
+
+void QgsServer::saveEnvVar( const QString& variableName )
+{
+  const char* env = getenv( variableName.toLocal8Bit() );
+  if ( !env )
+  {
+    return;
+  }
+
+  mEnvironmentVariables.insert( variableName, QString::fromLocal8Bit( env ) );
+}
+

src/server/qgsserver.h

@@ -93,6 +93,12 @@ class SERVER_EXPORT QgsServer
 #endif
 
   private:
+
+    void saveEnvVars();
+
+    /** Saves environment variable into mEnvironmentVariables if defined*/
+    void saveEnvVar( const QString& variableName );
+
     // All functions that where previously in the main file are now
     // static methods of this class
     static QString configPath( const QString& defaultConfigPath,
@@ -128,6 +134,9 @@ class SERVER_EXPORT QgsServer
     static int sArgc;
     static QgsApplication* sQgsApplication;
     static bool sCaptureOutput;
+
+    /** Pass important environment variables to the fcgi processes*/
+    QHash< QString, QString > mEnvironmentVariables;
 };
 #endif // QGSSERVER_H