Add exception handler if Channel Finder Server is not available

PythonServer/pos-python-server.py

@@ -59,14 +59,17 @@ class myHandler(BaseHTTPRequestHandler):
                     search_string=search_string[:-1]
                     search_string+=','
                 search_string=search_string[:-1]
-                result = cf.find(name=search_string)
+                try:
+                    result = cf.find(name=search_string)
+                    if len(result)==0:
+                        returnlist='No PV found.'
+                    else:
+                        for pv in result:
+                            returnlist+='<a href="#" onclick="searchPV(\''+pv['name']+'\')">'+pv['name']+'</a>'
+                            returnlist+='<br>'
+                except:
+                    returnlist='Channel Finder Server Not Available.'
 
-                if len(result)==0:
-                    returnlist='No PV found.'
-                else:
-                    for pv in result:
-                        returnlist+='<a href="#" onclick="searchPV(\''+pv['name']+'\')">'+pv['name']+'</a>'
-                        returnlist+='<br>'
                 self.wfile.write(bytes(json.dumps({'pvs':returnlist}), "utf-8"))
                 return