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Posted to users@wicket.apache.org by Christian Huber <hu...@butterbrot.org> on 2011/09/19 19:50:36 UTC

How to handle errors in RequestCycle.onEndRequest

Hi all,

I just noticed that exceptions occuring in onEndRequest of a 
RequestCycle somehow do not reflect on the respone page.

I am using an AjaxFallbackButton and the OSIV pattern and thus commit my 
database changes in onEndRequest, now if an exception occurs here I do 
get a log entry but I cannot get my application to display the 
corresponding error to the user.

Adding a message to the feedback panel does not help as the message gets 
displayed on the following request but not the current one. I also tried 
using various AbortExceptions like RedirectToUrlException, 
RestartResponseException or AbortWithWebErrorCodeException. This did 
improve the situation as far as the request did get aborted but there is 
still no visual display of the error.

Setting the ResponsePage directly and/or setting redirect to true did 
not change anything.

This sounds like a common problem and so I guess there is an easy 
solution to it, but I just don't get it right now, so any pointers are 
welcome.

Thanks, Chris

-- 
The Sanity Resort <http://sanityresort.blogspot.com/>

Re: How to handle errors in RequestCycle.onEndRequest

Posted by Igor Vaynberg <ig...@gmail.com>.

onEndRequest() is too late to handle any kind of user-facing exception
because the response has already been committed. just like in
detach(). the only thing that can happen here is that the exception
can be logged.

-igor


On Sat, Sep 24, 2011 at 5:14 AM, Christian Huber <hu...@butterbrot.org> wrote:
> Thanks for your reply Dan.
>
> My application is rather simplistic from a persistence point of view,
> meaning that I want all persistence actions from a request to be atomic. Of
> course I could move the commit calls out of the RequestCycle class which
> would solve this particular problem.
>
> But does that mean there is no way to properly handle an exception occuring
> in RequestCycle#endOfRequest to redirect to an error page or add error
> messages to the current page?
>
> I figured this should be doable, or could it mean that I broke something
> with my architecture?
>
>
> The Sanity Resort <http://sanityresort.blogspot.com/>
>
> Am 24.09.2011 12:46, schrieb Dan Retzlaff:
>>
>> So you open both a session and a transaction at the beginning of a
>> request,
>> and commit/close them at the end? I think it's more common to only have
>> the
>> session last through the request, and to have transactions
>> started/committed
>> around DAO or controller methods. This gives your app more control over
>> transaction boundaries and exceptions. Since this can mean lots of
>> begin/try/commit/finally/rollback stuff, it's also common to use AOP (e.g.
>> from Guice or Spring) to do that stuff without code for each instance.
>>
>> Dan
>>
>> On Sat, Sep 24, 2011 at 1:47 AM, Christian
>> Huber<hu...@butterbrot.org>wrote:
>>
>>> Hi again,
>>>
>>> sorry for reposting, but as I am still struggling with this I thought I
>>> try
>>> bumping this thread.
>>>
>>> Any hints would be very welcome.
>>>
>>> Cheers, Chris
>>>
>>>
>>> The Sanity
>>> Resort<http://sanityresort.blogspot.**com/<http://sanityresort.blogspot.com/>
>>> Am 19.09.2011 19:50, schrieb Christian Huber:
>>>
>>>  Hi all,
>>>>
>>>> I just noticed that exceptions occuring in onEndRequest of a
>>>> RequestCycle
>>>> somehow do not reflect on the respone page.
>>>>
>>>> I am using an AjaxFallbackButton and the OSIV pattern and thus commit my
>>>> database changes in onEndRequest, now if an exception occurs here I do
>>>> get a
>>>> log entry but I cannot get my application to display the corresponding
>>>> error
>>>> to the user.
>>>>
>>>> Adding a message to the feedback panel does not help as the message gets
>>>> displayed on the following request but not the current one. I also tried
>>>> using various AbortExceptions like RedirectToUrlException,
>>>> RestartResponseException or AbortWithWebErrorCodeException**. This did
>>>> improve the situation as far as the request did get aborted but there is
>>>> still no visual display of the error.
>>>>
>>>> Setting the ResponsePage directly and/or setting redirect to true did
>>>> not
>>>> change anything.
>>>>
>>>> This sounds like a common problem and so I guess there is an easy
>>>> solution
>>>> to it, but I just don't get it right now, so any pointers are welcome.
>>>>
>>>> Thanks, Chris
>>>>
>>>>
>

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