[Zope3-dev] Re: revisiting IResult (for in-Zope pipelining)

[Philipp von Weitershausen]

Gary Poster wrote:
>>> Can we quickly figure out a reasonable way to make the new, improved 
>>> interface ready for 3.4?
>>
>> I don't know if it is too late for 3.4.
> 
> With the schedule Christian mentioned, it seems like it would be 
> possible.  As you point out later, it doesn't make a huge difference to 
> me practically because of the new egg distribution story.  That said, if 
> it made it to 3.4 in might encourage more exploration of the pipelining.

It looks like the change is mostly mechanical for now (moving IResult to 
a more prominent place).

>>> (I don't define __iter__ explicitly since I've been reminded too many 
>>> times that __getitem__ is still a workable iteration protocol.)
>>
>> I don't agree.  Support by Python for __getitem__-based iteration is 
>> for backward compatibility. New code should not use __getitem__, but 
>> should use __iter__/next.  It would be clearer IMO to include __iter__ 
>> in the interface.
> 
> Great by me. :-)

+1 to __iter__ as already mentioned in my other email.

>>> Then we look up the IResult using the same multiadaptation of 
>>> (result, request) we have now, which makes it possible to set headers 
>>> in the adapter if desired.
>>>
>>> An IResult adapter could then be as simple as this:
>>>
>>> @zope.interface.implementer(zope.publisher.interfaces.http.IResult)
>>> @zope.component.adapter(
>>>     SomeCoolLXMLThing,
>>>     zope.pubisher.interfaces.browser.IBrowserRequest)
>>> def postprocessLXML(lxml, request):
>>>     do_some_cool_transformation(lxml)
>>>     return output_to_html(lxml)
>>
>> Assuming that output_to_html returns a string, we should not encourage 
>> this unless we say that the publisher is going to special-case strings 
>> to iterate over them efficiently.
> 
> I'm tempted to do this (i.e., special-case strings).  I might talk with 
> you about this off-line.

I wouldn't mind keeping the IResult API WSGI-ish, meaning that you would 
have to return [output_to_html(lxml)] to make the above efficient, or 
chunk the strings and yield them.


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