r.in.wms: catch incorrect WMS url input

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74338 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/r.in.wms/wms_drv.py

@@ -58,6 +58,7 @@ class WMSDrv(WMSBase):
         @return temp_map with downloaded data
         """
         grass.message(_("Downloading data from WMS server..."))
+        server_url = self.params["url"]
 
         if "?" in self.params["url"]:
             self.params["url"] += "&"
@@ -182,6 +183,8 @@ class WMSDrv(WMSBase):
                     grass.fatal(_("WMS server unknown error"))
 
             temp_tile_pct2rgb = None
+            if tile_dataset_info.RasterCount < 1:
+                grass.fatal(_("WMS server error: no band(s) received. Is server URL correct? <%s>") % server_url )
             if tile_dataset_info.RasterCount == 1 and \
                tile_dataset_info.GetRasterBand(1).GetRasterColorTable() is not None:
                 # expansion of color table into bands