error handling for giving the predictor non-existent UUIDs

predict/js/pred.js

@@ -37,12 +37,17 @@ $(document).ready(function() {
         populateFormByUUID(current_uuid);
         appendDebug("Trying to get progress JSON");
         $.getJSON("preds/"+current_uuid+"/progress.json", function(progress) {
-            appendDebug("Got progress JSON from server for UUID");
-            if ( progress['error'] || !progress['pred_complete'] ) {
-                appendDebug("The prediction was not completed correctly, quitting");
+            if ( progress != null ) {
+                appendDebug("Got progress JSON from server for UUID");
+                if ( progress['error'] || !progress['pred_complete'] ) {
+                    appendDebug("The prediction was not completed correctly, quitting");
+                } else {
+                    writePredictionInfo(current_uuid, progress['run_time'], progress['gfs_timestamp']);
+                    getCSV(current_uuid);
+                }
             } else {
-                writePredictionInfo(current_uuid, progress['run_time'], progress['gfs_timestamp']);
-                getCSV(current_uuid);
+                appendDebug("Couldn't find the progress JSON for the supplied UUID");
+                throwError("You requested a UUID that doesn't seem to exist on the server. Please re-run");
             }
         });
     }