Cancel an Asynchronous Request in a Flow Local Action

If an asynchronous request times out, the flow executes the local action's fault connector and sets $Flow.FaultMessage to the error message. However, the original request isn't automatically canceled. To abort an asynchronous request, use the cancelToken parameter available in the invoke method.

note: By default, requests time out after 120 seconds. To override the default, assign a different Integer to the component's timeout attribute.

In this client-side controller, the invoke method returns a Promise. When the method has done all it needs to do, it completes the call and control returns to the flow.

If the request is successful, the method uses resolve() to execute the next element in the flow after this action.
If the request isn't successful, it uses reject() to execute the local action’s fault connector and sets $Flow.FaultMessage to “My error message”.
If the request takes too long, it uses cancelToken.promise.then to abort the request.

({
   invoke : function(component, event, helper) {
      var cancelToken = event.getParam("arguments").cancelToken;

      return new Promise(function(resolve, reject) {
         var xhttp = new XMLHttpRequest();

         // Do something, like get data from
         // a database behind your firewall
         xhttp.onreadystatechange = $A.getCallback(function() {
            if (/* request was successful */) {
               // Complete the call and return to the flow
               resolve();
            } else {
               reject(new Error("My error message"));
            }
         });

         // If the Promise times out, abort the request and
         // pass set $Flow.FaultMessage to "Request timed out"
         cancelToken.promise.then(function(error) {
            xhttp.abort();
            reject(new Error("Request timed out."));
         });

      });
   }
})

See Also