[Zope3-dev] Fix for request retry on ConflictError

[Sven Schomaker]

Jim Fulton wrote:
> PLease submit a collector issue at:
>
>   http://www.zope.org/Collectors/Zope3-dev
>
> A test would be especially helpful.
>
Yeehaw, I was afraid someone would ask for such a thing.
I must admit I actually wasn't able to write it up to now,
since I'm not too familiar with all the traversal stuff and
the like and howto setup a test for that issue.

Poor me - I figured out the solution by torturing our app
with a bunch of simultaneous requests and provoking
some ConflictErrors.

Since that is not helpful at all, someone may help me on
writing a formal test?

greetings,

Sven

> Jim
>
> On Jul 18, 2006, at 4:28 AM, Sven Schomaker wrote:
>
>> Hi all,
>>
>> the retry of a request in case of a ConflictError in Zope 3.2.1 fails
>> with a NotFound error, while looking up the requested view in
>> zope/app/traversing/namespace.py (line 362).
>>
>> It seems as the newly created request (in request.retry()) does
>> somehow not satisfy the adapter prerequisites to successfully
>> look up a view in zope.component.queryMultiadapter.
>>
>> I did not dig too deep to find out what exactly goes wrong in the old
>> statement used to create the new request instance, but I suppose
>> somehow not all specifications (interfaces) of the original request
>> are set up on the new request. Nevertheless I came up with a (quick)
>> fix in zope/publisher/http.py that circumvents the issue.
>>
>> I don't know whether this is already fixed in the trunk or the fix
>> appeals to the devs with check-in permissions, but maybe someone
>> wants to look at it and check it in (or comes up with a better/more
>> precise one:)).
>>
>>
>> greetings,
>>
>> Sven Schomaker
>>
>>
>> Index: http.py
>> ===================================================================
>> --- http.py     (revision 178)
>> +++ http.py     (working copy)
>> @@ -15,6 +15,7 @@
>>
>> $Id: http.py 41004 2005-12-23 21:01:20Z jim $
>> """
>> +from copy import copy
>> import re, time, random
>> from cStringIO import StringIO
>> from urllib import quote, unquote, splitport
>> @@ -435,13 +436,12 @@
>>         'See IPublisherRequest'
>>         count = getattr(self, '_retry_count', 0)
>>         self._retry_count = count + 1
>> -
>> -        new_response = self.response.retry()
>> -        request = self.__class__(
>> +        request = copy(self)
>> +        request.__init__(
>>             # Use the cache stream as the new input stream.
>>             body_instream=self._body_instream.getCacheStream(),
>>             environ=self._orig_env,
>> -            response=new_response,
>> +            response=self.response.retry(),
>>             )
>>         request.setPublication(self.publication)
>>         request._retry_count = self._retry_count
>>
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>>
>
> -- 
> Jim Fulton            mailto:jim at zope.com        Python Powered!
> CTO                 (540) 361-1714            http://www.python.org
> Zope Corporation    http://www.zope.com        http://www.zope.org
>
>
>


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