WebObjects/Web Applications/Development/Custom Error Handling

From Wikibooks, open books for an open world
< WebObjects
Jump to: navigation, search

Exception Page[edit]

To provide a custom error handler when an exception is thrown, override the method:

 public WOResponse handleException (java.lang.Exception anException, WOContext aContext) { }

For example:

 public WOResponse handleException(Exception _exception, WOContext _context) {
   Session session = (Session) _context.session();
   // do something to notify user of exception, maybe put a message in the session here ...
   WOResponse response;
   if (/* you can't handle exception*/) {
     response = super.handleException(_exception, _context);
   }
   else {
     response = pageWithName(YourExceptionPage.class.getName(), _context).generateResponse();
   }
   return response;
 } 

Session Expired[edit]

To provide a custom error handler when an exception is thrown, override the method:

 public WOResponse handleSessionRestorationErrorInContext(WOContext _context) {

For example:

 public WOResponse handleSessionRestorationErrorInContext(WOContext _context) {
   Session session = (Session) _context.session();
   // do something to notify user of exception, maybe put a message in the session here ...
   WOResponse response = pageWithName(YourErrorPage.class.getName(), _context).generateResponse();
   return response;
 }

Your Request Produced an Error[edit]

Chuck Hill[edit]

This message started to appear in WO 5.2 when an exception was raised in a DirectAction, but only in deployed applications. Here is what is happening:

WODisplayExceptionPages true or false to enable or disable the generation of WOExceptionPages for direct action requests. Default is true in development mode and false in deployment mode.

From http://developer.apple.com/documentation/WebObjects/WOAppProperties/AppProperties/chapter_1_section_1.html

If the page being returned throws during appendToResponse and the app is deployed, all that is displayed is a blank page with the words "Your request produced an error".

To avoid this, either add this to the launch agruments:

 -DWODisplayExceptionPages=true

Or change the main method in your Application class to look like this:

 public static void main(String argv[]) {
   System.setProperty("WODisplayExceptionPages", "true");
   WOApplication.main(argv, Application.class);
 }

This won't work if you put it in the constructor.