[Zope-dev] Zope 2: ZPublisher exception handling

[yuppie]

Hi!


Tres Seaver wrote:
> yuppie wrote:
>> yuppie wrote:
>>> In Zope 2.10 'raise_standardErrorMessage', 'zpublisher_exception_hook'
>>> and therefore 'Publish.publish' did always (re-)raise errors after
>>> rendering. That made sure 'HTTPResponse.exception' was called and
>>> CookieCrumbler was able to hook into 'HTTPResponse._unauthorized'.
>>>
>>> I'm now trying to figure out how this bug could be fixed:
>>> https://bugs.launchpad.net/zope-cmf/+bug/558340
>>
>> For the record:
>>
>> Meanwhile I figured out that there is a related launchpad issue
>> https://bugs.launchpad.net/zope2/+bug/372632
>
> Do you have a suggestion for resolving those two bugs?

The original issue reported in 
https://bugs.launchpad.net/zope2/+bug/372632 seems to be fixed. The 
issue discussed in comment #15 and later is basically the same as in 
https://bugs.launchpad.net/zope-cmf/+bug/558340.

So there is only *one* issue:

If errors are rendered by 'raise_standardErrorMessage' or by an error 
view they are not re-raised. In that case the error handling in 
'publish_module_standard' and 'HTTPResponse.exception' is no longer invoked.

I'm not sure how to resolve this.

Approach 1: We try to restore the old behavior. The changes were made 
because the old machinery didn't work with exceptions like 
zope.publisher.interfaces.NotFound, but I'm optimistic we can find a 
less intrusive fix for that.

Approach 2: The _unauthorized call seems to be the only part of the old 
error handling that people are actually missing. We could try to add a 
new hook for that and deprecate big parts of the old code. But is that 
old code really useless?

>> and a workaround for the CookieCrumbler issue:
>> http://dev.plone.org/collective/changeset/92340
>
> Hmm, registering an exception view which re-raises the exception is
> definitely suggestive of something wrong in the plumbing.

Yes. But *if* we don't want restore the old behavior, we could move 
CookieCrumbler's complete redirect logic into an error view. And get rid 
of _unauthorized.


Cheers,

	Yuppie