[Seaside] state in request handler

[Norbert Hartl]

Am 13.04.2012 um 11:37 schrieb Lukas Renggli:

> On 13 April 2012 10:26, Norbert Hartl <norbert at hartl.name> wrote:
>> 
>> Am 13.04.2012 um 08:13 schrieb Milan Mimica:
>> 
>> On 12 April 2012 23:46, Norbert Hartl <norbert at hartl.name> wrote:
>>> 
>>> I'm using a seaside rest handler and I was wondering today how concurrency
>>> issues are handeld there. The request handler is a component that is always
>>> the same object for incoming requests. I need to set  a heavy weight
>>> component at incoming request and I want to have it accessible until the
>>> response is send. Where is the be place to put such kind of state?
>>> Starting to add an instance variable in the request handler I had the
>>> impression this is a bad thing to do. And then I was wondering how multiple
>>> threads are handled in seaside. Or better what operation can be considered
>>> thread safe and where I need to put extra effort to protect intermediate
>>> state while processing. My component needs to be initialized by the incoming
>>> request context and is accessed multiple times until process has finished.
>> 
>> 
>> You could make it thread-local. Look at how WACurrentRequestContext is
>> implemented.
>> 
>> I see. Although I think thread-locality here is a coincidence. And
>> WARequestContext is adaptive so I could hook my stuff onto it. I need to
>> make my component aware of the request context. I'm not convinced this is
>> the best way to go but it would work I think.
>> Probably that solves my other problem, too. With having a state within the
>> request handler there needs to be a location where this state is to be
>> resetted. I thought handleFiltered: would be called only once. But this is
>> not true at least not when running it inside a test case. Or I need to try
>> to investigate further.
> 
> I would just create a new object for each incoming request in the
> Seaside request handler. Like this you can safely keep your state
> separate from all other incoming requests and it gets garbage
> collected as soon as the request completes.
> 
> SeasideRequestHandler>>#handleRequest: aRequestContext
>     ^ MyRequestHandler new handle: aRequestContext
> 
Right. I think this is the right idea to nail it.

thanks,

Norbert