Basic Customization > User Interface Customization > Constructing Wizards > Handling External Requests Using an MVC Controller > Unauthorized Action Handling
  
Unauthorized Action Handling
In case, invalid action or type is provided or the user does not have access to perform the operation on Windchill server, an error will be displayed to the external system user.
Call back to the external system
When a request is made to the Windchill system, a form field with the name externalURL is populated with the external URL information, please see example below. If no information is provided Windchill object will be created when a request is made, however no feedback of the newly created object will be provided. A “GET” form method is used to pass back the data.
Accessing the created Windchill objects
The external URL will be appended with a new parameter as “UFIDs” in the caller server. The “UFIDs” parameter can be read to retrieve the values. The values are on JSON format and the values can be accessed using the key “UFIDs”.
Assumptions
1. User is authorized with required credentials for the provided external URL.
2. The input field for the external URL should be provided with name=externalURL. An example external URL would look like : http://<externalURL>/<host-name>/ptc1/externalTest
Handling multiple creation of OIDs
The external call back feature supports returning multiple OIDs for the request operation. In the JSONObject key “UFIDs” will contain UFID values.