[ZPT] Re: [Zope] Problem with alternate path and request

[Ian Bicking]

On Monday, October 20, 2003, at 02:37 PM, Fernando Martins wrote:
> Ian Bicking wrote:
>> On Sunday, October 19, 2003, at 06:00 PM, Fernando Martins wrote:
>>>>>   <p tal:content="request/HTTP_X_FORWARDED_FOR |
>>>> request/REMOTE_ADDR"></p>
>>>>>
>>>>> doesn't work as expected: HTTP_X_FORWARDED_FOR returns an empty
>>>>> string
>>>>> rather than failling in favor of REMOTE_ADDR.
>>>>
>>>> This means that something defined "HTTP_X_FORWARDED_FOR" even
>>>> when you did not use virtualisation.
>>>>
>>>> You know, that you can view the request with
>>>> '<p tal:content="structure request">'?
>>>>
>>>
>>> Yes, and I think it's a bug because it doesn't appear in the request.
>>
>> If you want to confirm this, you should try to use
>> container.REQUEST.HTTP_X_FORWARDED_FOR from a Python script, or maybe
>> just tal:content="python: repr(request.HTTP_X_FORWARDED_FOR)" -- even
>> though the request doesn't list that variable among its headers, it 
>> may
>> still return a value for that attribute.  The only way to test if an
>> attribute exists is to attempt to get the attribute.  Perhaps (I don't
>> know) the request object returns "" for any HTTP_* attribute that is
>> not found.
>>
>
> Ok, tried it and got no error, just an empty string.
>
> So, it is either a bug on the request object which contains the 
> attribute
> HTTP_X_FORWARDED_FOR when it shouldn't (i.e., when the request went 
> from the
> client straight to Zope). But maybe it should always have it.
>
> Or it is a bug in the "structure request" which doesn't display the
> attribute even if it is there.

I assume it was a design choice, and changing it would break backward 
compatibility.  I'd recommend just using tal:content="python: 
request.HTTP_X_FORWARDED_FOR or request.REMOTE_ADDR".

> BTW, which method is implicitly called to generate the HTML 
> representation
> of the objects (like in "structure request")?

__str__ should be it.  You'll want to pay attention to __getattr__ as 
well, as HTTPRequest's __getattr__ probably is what returns an empty 
string for HTTP_* variables that aren't found.

--
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org