More WMS improvements:

* Errors report to the GUI in many more cases (not just the console when QGIS_DEBUG was defined) - both HTTP connection errors and WMS Service Exceptions from the server.  However, non-standard HTTP responses (e.g. 500 Server Error) are not handled yet.
* The WMS selection GUI was cleaned up in the CRS selection group box - as users select layers, the number of available CRSs is displayed.  Also, the current selection is now displayed as the friendly description, not the proj4 string.
* There is a better chance of a valid CRS being sent to the server in more situations (with WMS therefore appearing to work more often!).
* In QgsSpatialRefSys, initialise the mIsValidFlag properly.



git-svn-id: http://svn.osgeo.org/qgis/trunk@4979 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/core/qgsrasterdataprovider.h

@@ -94,18 +94,24 @@ class QgsRasterDataProvider : public QgsDataProvider
     virtual QString getMetadata() = 0;
 
     /**
+     * \brief   Returns the caption error text for the last error in this provider
+     *
      * If an operation returns 0 (e.g. draw()), this function
      * returns the text of the error associated with the failure.
      * Interactive users of this provider can then, for example,
      * call a QMessageBox to display the contents.
+     *
      */
     virtual QString errorCaptionString() = 0;
 
     /**
+     * \brief   Returns the verbose error text for the last error in this provider
+     *
      * If an operation returns 0 (e.g. draw()), this function
      * returns the text of the error associated with the failure.
      * Interactive users of this provider can then, for example,
      * call a QMessageBox to display the contents.
+     *
      */
     virtual QString errorString() = 0;
 

src/gui/qgsmaplayer.h

@@ -290,15 +290,15 @@ class QgsMapLayer : public QObject
      * Interactive users of this provider can then, for example,
      * call a QMessageBox to display the contents.
      */
-    QString errorCaptionString();
+    virtual QString errorCaptionString();
 
     /**
      * If an operation returns 0 (e.g. draw()), this function
      * returns the text of the error associated with the failure.
      * Interactive users of this provider can then, for example,
      * call a QMessageBox to display the contents.
      */
-    QString errorString();
+    virtual QString errorString();
 
 
 public  slots:

src/gui/qgsserversourceselect.cpp

@@ -35,11 +35,14 @@
 
 #include <iostream>
 
+static long DEFAULT_WMS_EPSG = 4326;  // WGS 84
+
+
 QgsServerSourceSelect::QgsServerSourceSelect(QgisApp * app, QWidget * parent, Qt::WFlags fl)
   : QDialog(parent, fl),
     qgisApp(app),
-    wmsProvider(0),
-    m_Epsg(0)
+    mWmsProvider(0),
+    m_Epsg(DEFAULT_WMS_EPSG)
 {
   setupUi(this);
   connect(btnCancel, SIGNAL(clicked()), this, SLOT(reject()));
@@ -61,12 +64,11 @@ QgsServerSourceSelect::QgsServerSourceSelect(QgisApp * app, QWidget * parent, Qt
   hbox->addStretch();
   btnGrpImageEncoding->setLayout(hbox);
 
+  // set up the WMS connections we already know about
   populateConnectionList();
-  // connect the double-click signal to the addSingleLayer slot in the parent
-
-  //disable the 'where clause' box for 0.4 release
-  //  groupBox3->hide();
 
+  // set up the default WMS Coordinate Reference System
+  labelCoordRefSys->setText( descriptionForEpsg(m_Epsg) );
 }
 
 QgsServerSourceSelect::~QgsServerSourceSelect()
@@ -143,11 +145,14 @@ void QgsServerSourceSelect::on_btnHelp_clicked()
 
 }
 
-void QgsServerSourceSelect::populateLayerList(QgsWmsProvider* wmsProvider)
+bool QgsServerSourceSelect::populateLayerList(QgsWmsProvider* wmsProvider)
 {
   std::vector<QgsWmsLayerProperty> layers;
 
-  layers = wmsProvider->supportedLayers();
+  if (!wmsProvider->supportedLayers(layers))
+  {
+    return FALSE;
+  }
 
   lstLayers->clear();
 
@@ -202,6 +207,8 @@ void QgsServerSourceSelect::populateLayerList(QgsWmsProvider* wmsProvider)
   {
     btnAdd->setEnabled(FALSE);
   }
+
+  return TRUE;
 }
 
 
@@ -344,18 +351,26 @@ void QgsServerSourceSelect::on_btnConnect_clicked()
   // load the server data provider plugin
   QgsProviderRegistry * pReg = QgsProviderRegistry::instance();
 
-  wmsProvider = 
+  mWmsProvider = 
     (QgsWmsProvider*) pReg->getProvider( "wms", m_connInfo );
 
-  if (wmsProvider)
+  if (mWmsProvider)
   {
-    connect(wmsProvider, SIGNAL(setStatus(QString)), this, SLOT(showStatusMessage(QString)));
+    connect(mWmsProvider, SIGNAL(setStatus(QString)), this, SLOT(showStatusMessage(QString)));
 
-    populateLayerList(wmsProvider);
+    if (!populateLayerList(mWmsProvider))
+    {
+      showError(mWmsProvider);
+    }
   }
   else
   {
-    // TODO: Let user know we couldn't initialise the WMS provider
+    // Let user know we couldn't initialise the WMS provider
+    QMessageBox::warning(
+      this,
+      tr("WMS Provider"),
+      tr("Could not open the WMS Provider")
+    );
   }
 
 }
@@ -375,12 +390,12 @@ void QgsServerSourceSelect::on_btnAdd_clicked()
 
 void QgsServerSourceSelect::on_btnChangeSpatialRefSys_clicked()
 {
-  if (!wmsProvider)
+  if (!mWmsProvider)
   {
     return;
   }
 
-  QSet<QString> crsFilter = wmsProvider->supportedCrsForLayers(m_selectedLayers);
+  QSet<QString> crsFilter = mWmsProvider->supportedCrsForLayers(m_selectedLayers);
 
   QgsLayerProjectionSelector * mySelector =
     new QgsLayerProjectionSelector(this);
@@ -393,15 +408,15 @@ void QgsServerSourceSelect::on_btnChangeSpatialRefSys_clicked()
 
   if (mySelector->exec())
   {
-    // TODO: assign EPSG back to the WMS provider
     m_Epsg = mySelector->getCurrentEpsg();
   }
   else
   {
     // NOOP
   }
 
-  labelSpatialRefSys->setText( mySelector->getCurrentProj4String() );
+  labelCoordRefSys->setText( descriptionForEpsg(m_Epsg) );
+//  labelCoordRefSys->setText( mySelector->getCurrentProj4String() );
 
   delete mySelector;
 
@@ -477,6 +492,18 @@ void QgsServerSourceSelect::on_lstLayers_selectionChanged()
   // If we got some selected items, let the user play with projections
   if (newSelectedLayers.count() > 0)
   {
+    // Determine how many CRSs there are to play with
+    if (mWmsProvider)
+    {
+      QSet<QString> crsFilter = mWmsProvider->supportedCrsForLayers(newSelectedLayers);
+
+      gbCRS->setTitle(
+                       QString( tr("Coordinate Reference System (%1 available)") )
+                          .arg( crsFilter.count() )
+                     );
+
+    }
+
     btnChangeSpatialRefSys->setEnabled(TRUE);
   }
   else
@@ -510,6 +537,7 @@ QStringList QgsServerSourceSelect::selectedStylesForSelectedLayers()
   return m_selectedStylesForSelectedLayers;
 }
 
+
 QString QgsServerSourceSelect::selectedImageEncoding()
 {
   // TODO: Match this hard coded list to the list of formats Qt reports it can actually handle.
@@ -525,6 +553,7 @@ QString QgsServerSourceSelect::selectedImageEncoding()
 
 }
 
+
 QString QgsServerSourceSelect::selectedCrs()
 {
   if (m_Epsg)
@@ -538,6 +567,7 @@ QString QgsServerSourceSelect::selectedCrs()
   }
 }
 
+
 void QgsServerSourceSelect::showStatusMessage(QString const & theMessage)
 {
   labelStatus->setText(theMessage);
@@ -547,4 +577,28 @@ void QgsServerSourceSelect::showStatusMessage(QString const & theMessage)
 }
 
 
+void QgsServerSourceSelect::showError(QgsWmsProvider * wms)
+{
+  QMessageBox::warning(
+    this,
+    wms->errorCaptionString(),
+    tr("Could not understand the response.  The") + " " + wms->name() + " " +
+      tr("provider said") + ":\n" +
+      wms->errorString()
+  );
+
+}
+
+
+QString QgsServerSourceSelect::descriptionForEpsg(long epsg)
+{
+  // We'll assume this function isn't called very often,
+  // so please forgive the lack of caching of results
+
+  QgsSpatialRefSys qgisSrs = QgsSpatialRefSys(epsg, QgsSpatialRefSys::EPSG);
+
+  return qgisSrs.description();
+}
+
+
 // ENDS

src/gui/qgsserversourceselect.h

@@ -96,18 +96,30 @@ public slots:
     //! Set status message to theMessage
     void showStatusMessage(QString const & theMessage);
 
+    //! show whatever error is exposed by the QgsWmsProvider.
+    void showError(QgsWmsProvider * wms);
+
 
 private:
 
-    //! Populate the layer list - private for now.
-    void populateLayerList(QgsWmsProvider* wmsProvider);
+    /**
+     * \brief Populate the layer list - private for now.
+     *
+     * \retval FALSE if the layers could not be retreived or parsed - 
+     *         see mWmsProvider->errorString() for more info
+     */
+    bool populateLayerList(QgsWmsProvider* wmsProvider);
 
     //! Populate the image encoding button group - private for now.
     void populateImageEncodingGroup(QgsWmsProvider* wmsProvider);
 
     //! Returns the common CRSs for the selected layers.
     std::set<QString> crsForSelection();
 
+    //! Returns a textual description for the EPSG number
+    QString descriptionForEpsg(long epsg);
+
+
     QString m_connName;
     QString m_connInfo;
     QStringList m_selectedLayers;
@@ -126,7 +138,7 @@ public slots:
     QButtonGroup* m_imageFormatBtns;
 
     //! The WMS provider that retreives information for this dialog
-    QgsWmsProvider * wmsProvider;
+    QgsWmsProvider * mWmsProvider;
 
     static const int context_id = 710979116;
 };

src/gui/qgsspatialrefsys.cpp

@@ -26,9 +26,16 @@
 
 //--------------------------
 
-QgsSpatialRefSys::QgsSpatialRefSys() : mMapUnits(QGis::UNKNOWN) {}
+QgsSpatialRefSys::QgsSpatialRefSys()
+  : mMapUnits(QGis::UNKNOWN),
+    mIsValidFlag(0)
+{
+  // NOOP
+}
 
-QgsSpatialRefSys::QgsSpatialRefSys(QString theWkt) : mMapUnits(QGis::UNKNOWN)
+QgsSpatialRefSys::QgsSpatialRefSys(QString theWkt)
+  : mMapUnits(QGis::UNKNOWN),
+    mIsValidFlag(0)
 {
   createFromWkt(theWkt);
 }
@@ -41,10 +48,15 @@ QgsSpatialRefSys::QgsSpatialRefSys(long theSrsId,
                                    long theSRID,
                                    long theEpsg, 
                                    bool theGeoFlag)
-    : mMapUnits(QGis::UNKNOWN)
-{}
+  : mMapUnits(QGis::UNKNOWN),
+    mIsValidFlag(0)
+{
+  // NOOP
+}
 
-QgsSpatialRefSys::QgsSpatialRefSys(const long theId, SRS_TYPE theType) : mMapUnits(QGis::UNKNOWN)
+QgsSpatialRefSys::QgsSpatialRefSys(const long theId, SRS_TYPE theType)
+  : mMapUnits(QGis::UNKNOWN),
+    mIsValidFlag(0)
 {
   createFromId(theId, theType);
 }