Re: [PyWrapper-devel] Problem with PyWrapper, BioMoby and saveHttpBody function

[Javier de la T. <ja...@gm...>]

Hi all,

I just returned today from a week of holidays. I will take a look at =20
the emails this afternoon when i have a little bit more of time.

Cheers.

On 14/12/2007, at 14:30, D=C3=B6ring, Markus wrote:

> Ricardo,
> Ill have to look at it more closely, but I was the one to add this =20
> "save
> http body" stuff to pywrapper. I guess the moby part from javier =20
> was working
> correctly before.
>
> The situation with http body is a difficlut one unfortunately.
> When the streamed request comes in, we dont know what it is apart =20
> from the
> http content header and the content length header. It is streamed =20
> so you
> need to decide what to do just then inspecting the http headers.
>
> The idea is to only save the body if it is an xml content header, =20
> otherwise
> (for example html content from the webapps)  leave it alone so that =20=

> other
> libraries will not get confused (if you "save" the body, the stream =20=

> is gone
> and this will cause troubles for analysing request parameters later =20=

> via
> cherrypy.request).
>
> XML based messages that we use for TAPIR (but also for SOAP or others)
> should be send immediately in the http (POST) body and not encoded =20
> as a POST
> parameters in a http request. This is also part of the TAPIR spec =20
> but you
> can find that in OGC too. The idea is that all parameters are =20
> encoded in the
> XML message already. So you need to access the entire http body, =20
> something I
> didnt manage to do with CherryPy cause the framework already parses =20=

> a lot of
> http stuff by default for you. So I intercepted the http requests =20
> pretty
> early with custom cherrypy filters.
>
> I believe we should check why moby fails and simple fix the moby =20
> module to
> read the saved http body. Wouldnt that work?
>
>
> Markus
>
>
>
>
>
>
>
> "Ricardo Scachetti Pereira" wrote on 13.12.2007 19:42 Uhr:
>
>>     Hi Markus and Javi,
>>
>>     I'm trying to get PyWrapper to process BioMoby requests, but I =20=

>> got
>> stuck with the following problem.
>>
>>     The function saveHttpBody() (which I copy below - from file
>> ./webapp/pywrapper.py) looks at the request URL and decide whether or
>> not to save the http request body.
>>
>>     The problem is that the moby handler needs that the http body is
>> saved, but I don't know how to save it when a moby request comes. =20
>> To be
>> honest, I found the check n =3D=3D 'pywrapper' a little obscure. When =
=20
>> does
>> the http body gets saved anyway?
>>
>>     In any case, if I change the code so that the http body is always
>> saved, moby requests are handled without problems, but then the
>> PyWrapper config tool webapp breaks.
>>
>>     Is there a way for me to detect that the request is a moby one at
>> that point? But the request hasn't been parsed yet at that point, =20
>> right?
>>
>>     Anyway, I would really appreciate if you could shed some light on
>> the matter.
>>
>>     Thanks,
>>
>> Ricardo
>>
>>
>> PS: Here is the function:
>>
>> def saveHttpBody():
>>     """ Called after the request header has been read/parsed"""
>>     request =3D cherrypy.request
>>     # only process hook if pywrapper is being called
>>     n=3Drequest.path_info.lower().replace('/','')
>>     #print request.path_info / script_name
>>     log.debug("SaveHttpBody is looking at the request: %s"%n)
>>     if n =3D=3D 'pywrapper':
>>         para=3DcfgObj.PyWrapper.httpBodyParameter
>>         # get http body data
>>         dataLength =3D int(request.headers.get('Content-Length') or =
0)
>>         data =3D request.rfile.read(dataLength)
>>         # save http body & content-length as a new parameter. usually
>> __HTTP_BODY__
>>         request.params[para]=3D(cStringIO.StringIO(data), dataLength)
>>         # fake the input stream so CP can parse the body regularly
>>         if hasattr(request.rfile, 'maxlen'):
>>             request.rfile =3D
>> http.SizeCheckWrapper(rfile=3DcStringIO.StringIO(data),
>> maxlen=3Drequest.rfile.maxlen)
>>         else:
>>             request.rfile =3D
>> http.SizeCheckWrapper(rfile=3DcStringIO.StringIO(data), maxlen=3D0)
>>
>> cherrypy.request.hooks.attach('before_request_body', saveHttpBody,
>> failsafe=3DNone, priority=3DNone)
>>
>