Re: 404 does not delete cached entries using mod_disk_cache

[r....@t-online.de]

Anybody found some time / has some time to have a look at the patch?
This would be really great and appreciated.

Thanks

Rüdiger

r.pluem@t-online.de wrote:
> Sander Striker wrote:
> 
>>r.pluem@t-online.de wrote:
> 
> 
> [..cut..]
> 
> 
>>>Is this behaviour intended and compliant with the RFC?
>>
>>
>>Not to my knowlegde.  Given that mod_mem_cache and mod_disk_cache are doing
>>different things is pretty much indicative that one of the two is wrong ;).
> 
> 
> That was also my thought.
> 
> 
>>>The reason for this behaviour is that the remove_url function of
>>>mod_disk_cache is a dummy function
>>>(BTW: mod_mem_cache seems to really remove the cache entry in
>>>remove_url).
>>>If this behaviour is not intended I would have a look into this to
>>>create a patch.
>>
>>
>>Please do!
>>
> 
> 
> I created a patch but the problem turned out to be more complex than I thought
> originally. So a close look on the patch is definitely a good thing. Some comments:
> 
> 1. I had to adjust the cache provider API for remove_url as I need the request_rec
>    struct to remove the files correctly in mod_disk_cache.
> 
> 2. It turned out that 404 responses are not passed down the filter chain the way I expected.
>    Adjusting the default handler again proved that the changes to mod_disk_cache worked
>    (files got deleted), but this broke any error page handling in Apache. So I tried to address
>    this problem at other locations of the code. I detected two cases:
> 
>    1. Apache generated error messages or redirect to external source.
>    2. Custom local error documents.
> 
>    In the first case I use the insert_error_filter hook to ensure that the CACHE_SAVE filter
>    is reinserted to the filter chain if it has been inserted before during the request.
> 
>    In the second case the filter chain is run, but with the wrong URI. So I checked if there
>    is a previous request (r->prev) and if it has the same status code (this happens in a section
>    where we only handle uncachable status codes). If this is the case I assume that I should delete
>    the URL from the previous request from the cache.
> 
> So any comments / thoughts on this?
> 
> 
> Regards
> 
> Rüdiger