Add a warning on QGIS server when the versions don't corresponds

QGIS server and project file.

src/core/qgsproject.cpp

@@ -587,7 +587,7 @@ static void _getTitle( QDomDocument const &doc, QString &title )
 
    @returns the version string or an empty string if none found
  */
-static QgsProjectVersion _getVersion( QDomDocument const &doc )
+QgsProjectVersion getVersion( QDomDocument const &doc )
 {
   QDomNodeList nl = doc.elementsByTagName( "qgis" );
 
@@ -602,7 +602,7 @@ static QgsProjectVersion _getVersion( QDomDocument const &doc )
   QDomElement qgisElement = qgisNode.toElement(); // qgis node should be element
   QgsProjectVersion projectVersion( qgisElement.attribute( "version" ) );
   return projectVersion;
-} // _getVersion
+} // getVersion
 
 
 
@@ -857,7 +857,7 @@ bool QgsProject::read()
   QgsDebugMsg( "Project title: " + imp_->title );
 
   // get project version string, if any
-  QgsProjectVersion fileVersion =  _getVersion( *doc );
+  QgsProjectVersion fileVersion =  getVersion( *doc );
   QgsProjectVersion thisVersion( QGis::QGIS_VERSION );
 
   if ( thisVersion > fileVersion )

src/core/qgsproject.h

@@ -511,4 +511,6 @@ class CORE_EXPORT QgsProjectBadLayerDefaultHandler : public QgsProjectBadLayerHa
 
 };
 
+CORE_EXPORT QgsProjectVersion getVersion( QDomDocument const &doc );
+
 #endif

src/core/qgsprojectversion.cpp

@@ -62,6 +62,15 @@ bool QgsProjectVersion::operator==( const QgsProjectVersion &other ) const
           ( mSub == other.mSub ) );
 }
 
+/** Boolean equal operator
+ */
+bool QgsProjectVersion::operator!=( const QgsProjectVersion &other ) const
+{
+  return (( mMajor != other.mMajor ) ||
+          ( mMinor != other.mMinor ) ||
+          ( mSub != other.mSub ) );
+}
+
 /** Boolean >= operator
  */
 bool QgsProjectVersion::operator>=( const QgsProjectVersion &other ) const

src/core/qgsprojectversion.h

@@ -49,6 +49,10 @@ class CORE_EXPORT QgsProjectVersion
      */
     bool operator==( const QgsProjectVersion &other ) const;
 
+    /** Boolean equal operator
+     */
+    bool operator!=( const QgsProjectVersion &other ) const;
+
     /** Boolean >= operator
      */
     bool operator>=( const QgsProjectVersion &other ) const;

src/server/qgsconfigcache.cpp

@@ -23,6 +23,7 @@
 #include "qgswmsprojectparser.h"
 #include "qgssldconfigparser.h"
 #include "qgsaccesscontrol.h"
+#include "qgsproject.h"
 
 #include <QFile>
 
@@ -47,11 +48,37 @@ QgsConfigCache::~QgsConfigCache()
 
 QgsServerProjectParser* QgsConfigCache::serverConfiguration( const QString& filePath )
 {
+  QgsMessageLog::logMessage(
+    QString( "Open the project file '%1'." )
+    .arg( filePath ),
+    "Server", QgsMessageLog::INFO
+  );
+
   QDomDocument* doc = xmlDocument( filePath );
   if ( !doc )
   {
     return nullptr;
   }
+
+  QgsProjectVersion fileVersion = getVersion( *doc );
+  QgsProjectVersion thisVersion( QGis::QGIS_VERSION );
+
+  if ( thisVersion != fileVersion )
+  {
+    QgsMessageLog::logMessage(
+      QString(
+        "\n========================================================================="
+        "\n= WARNING: This project file was saved by an defferent version of QGIS. ="
+        "\n========================================================================="
+      ), "Server", QgsMessageLog::WARNING
+    );
+  }
+  QgsMessageLog::logMessage(
+    QString( "QGIS server version %1, project version %2" )
+    .arg( thisVersion.text() )
+    .arg( fileVersion.text() ),
+    "Server", QgsMessageLog::INFO
+  );
   return new QgsServerProjectParser( doc, filePath );
 }