[SalesForce] Generic error handler for Force.com Sites error pages

I know that I can override the standard error pages for a Force.com Site (Not Found, In Maintenance, Generic Error) with my own Visualforce pages and controller.

However, what I don't know how to do is find out what the root cause is for the Generic Error that is causing me to arrive at the page.

For example, if I haven't authorized one of the VF Pages that makes up my site to the Sites Guest User (via Profile or Permission Set), you land on the "http://xyz-developer-edition.na16.force.com/ticket is under construction. Stay tuned. Please email us if you need to get in touch." page.

But how do I know that the reason I'm on the Generic Error page is because of that specific problem?

My goal is to add a VF controller to the error page and email an administrator with a detailed explanation of the problem (and tips on how to resolve it).

Best Answer

After a long and laborious Case with Support, the conclusion is that there is no way to do what's suggested in the Question.

Any unhandled exception in a VF page served from Force.com Sites results in a 401/Unauthorized which is handled by the VF page configured as the "Unauthorized" handler in the Sites configuration.

If you add a Controller to this page and set an action on the page which invokes a method like so:

public class ErrorController{
    public PageReference landingAction(){
        System.debug('ERROR MESSAGE: ' + Site.getErrorMessage());
        System.debug('ERROR DESCRIPTION: ' + Site.getErrorDescription());
        return null;
    }
}

The ERROR MESSAGE is "Login is required to access this URL."

This is not correct, but according to Support, this is "working as designed" and as such, is completely useless.

Related Solutions

[SalesForce] Debug ViewState Problems in Force.com Sites VF Pages

Debugging the view state is a tricky one, as is debugging sites or customer portal pages. Each requires different approaches.

First, to debug un-authenticated sites page the simplest approach is to just view the page internally. Since un-authenticate sites pages will behave the same (mostly) in different contexts this usually gets the job done.

Second, to debug authenticated sites or customer portal pages it helps to add a 'runAs' param to your page, that when present will be used in place of UserInfo.getUserId() in queries. This way you can see the same data as if you were logged in as a the sites/customer portal user (mostly), but still have the full suite of debugging tools at your finger tips.

The caveat to both those approaches is that the permissions when run internally will be different. In those cases you'll want to fall back to preview mode (w/sites) or debug log monitoring. And when all else fails a good old binary search can do the trick.

Finally, for view state debugging, the challenge for me has also been that once you're over the view state limit you can't see any data about what the excess was. The only strategy here is to put limits on your queries until you get just below the limit and then use the view state inspector to figure out where you can optimize your controller memory storage. And lord help you if it turns out that your failing due to a large internal view state. This housekeeping section of the view state is wholly undocumented and can be very tricky to unwind one you start hitting it.

[SalesForce] Debugging force.com site visual force pages

Try one or more of the following:

Set the debug level to be less verbose (dev console). You'll get major errors back rather than each loop iteration showing up.

There are visualforce global parameters for page and exception. I placed these in a google analytics event on the page so I can see what's being thrown.

Wrap the whole page in a try/catch block, and do a system.debug(logginglevel.error, e) in the last catch. <==assuming you name all your exceptions e like I do). If the log verbosity is the main problem, combine this with #1.

If the error happens after the page loads, like on a save or other action, you could do #3 but use an apex message option to show the error that you're catching on the page (avoid the logs entirely).

Here's the GA script we use (prerequisite is that you have the GA async tag already on the page AND you have your GA id on the salesforce site config page).

<script type="text/javascript">
    var _gaq = _gaq || [];              
    _gaq.push(['_setAccount', '{!$Site.AnalyticsTrackingCode}']);
    _gaq.push([
       '_trackEvent', 
       'Page Errors', 
       '{!$Site.ErrorMessage}', 
       '{!$Site.OriginalUrl}--{!$Site.ErrorDescription} experienced by {!$User.id}']);                      
 </script>

Best of luck!

Best Answer

Related Solutions

[SalesForce] Debug ViewState Problems in Force.com Sites VF Pages

[SalesForce] Debugging force.com site visual force pages

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