On Sun, Oct 4, 2015 at 1:40 PM, Graham Leggett <[email protected]> wrote:
>
> The next bit of this is the ability to safely suspend a filter.
>
> A suspended filter is a filter that is waiting for some external event, a 
> callback of some kind, some timer that it might have set, and in the mean 
> time doesn’t want to be kicked. From the perspective of 
> ap_filter_should_yield() the filter has data in it and a well behaved 
> upstream filter should wait before sending anything further.
>
> The idea behind suspending filters over and above connections is that if two 
> separate filters want to suspend a connection, what stops them from stomping 
> on one another?

Why suspend a filter rather than the calling handler (on EAGAIN/EWOULDBLOCK)?

>
> I am thinking of the sharp end of mod_proxy_httpd (and friends) becoming an 
> async filter that suspends or not based on whether data is available on the 
> other connection. In the process, mod_proxy becomes asynchronous.

It seems that suspending the handlers would avoid rewriting them as filters.
Or is your plan to go for something like (mod_)serf?

Regards,
Yann.

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