Re: POE::Component::Server::TCP bug fixes, possibly incompatible

Most people want access to the raw socket to condition it before it's  
passed to POE::Wheel::ReadWrite.  ClientConnected is a bit late for  
this.  As Chris Williams mentioned, by the time ClientConnected is  
called, the socket has been conditioned and $_[HEAP]{client} is ready  
for action.

The component could provide a ClientConnecting callback that triggers  
before ClientConnected and allows the server to manipulate the  
socket.  ClientConnecting would perhaps return the socket if the  
connection should succeed, or return undef to disconnect right away.   
$_[HEAP]{client} would be undefined since the POE::Wheel::ReadWrite  
hasn't been created yet.

This was considered before, but I think it was rejected for some  
reason.  I think it was discussed in IRC, and the rationale was lost.   
Patches are welcome, but please also include tests and documentation.   
If the reason for discounting a ClientConnecting callback still  
applies, it might come to light during testing.

Unfortunately it seems that rejecting the connection from  
ClientConnecting would still incur the overhead of a POE::Session  
instantiation and destruction.  ClientConnecting must be called from  
the context of the per-connection session.

Applications with more specific requirements should take advantage of  
POE::Wheel::SocketFactory and POE::Wheel::ReadWrite directly.  These  
wheels provide more control and performance, with the trade-off being  
incrementally more application code.

Sorry for being all formal.  I still have my Work Head on.

-- 
Rocco Caputo - [email protected]


On Jul 16, 2009, at 07:29, Nick Williams wrote:

> Regarding the passing of the socket into clientconnected - I've  
> wished for
> this in the past, in order to be able to modify TCP options on the  
> socket,
> which didn't seem possible in the past... It would be nice if that was
> possible to get at this (either via some available API which I just  
> haven't
> noticed, or if these patches provide it at clientconnected time).
>
> Cheers,
> Nick.
>
> On Thu, Jul 16, 2009 at 12:06 PM, Chris 'BinGOs' Williams <
> [email protected]> wrote:
>
>> On Wed, Jul 15, 2009 at 06:59:12PM -0800, Michael Fowler wrote:
>>> On Wed, Jul 15, 2009 at 04:08:48AM -0400, Rocco Caputo wrote:
>>>> For starters, $_[ARG0] isn't guaranteed to contain anything in
>> particular.
>>>
>>> Well, it's guaranteed to contain whatever was passed as the 'args'
>>> argument to the POE::Session constructor, right?  When the session  
>>> is
>>> constructed, 'args' is [ $socket, $client_args ].  That 'args' value
>>> needs to remain, because the POE::Wheel::ReadWrite constructor  
>>> needs it.
>>> Having ClientConnected then mirror _start in terms of arguments  
>>> seems
>>> reasonable.
>>>
>>>
>>>> I think you're almost right.  The correct behavior would be for
>>>> ClientArgs to align with @_[ARG0..$#_].  This still breaks current
>> code,
>>>> but it's cleaner.
>>>
>>> Well, I don't mind breaking old code, but I think ARG0 being the  
>>> socket
>>> should be preserved.  Reaching into $heap->{client}- 
>>> >get_input_handle
>>> seems awkward.  Then again, perhaps it's breaking an abstraction  
>>> to have
>>> direct access to the socket outside of POE::Wheel::ReadWrite.
>>>
>>> The code I have that actually needs it would benefit from the  
>>> clarity of
>>> having the socket passed as ARG0.  Whether or not this breaks some
>>> possible future change in something...
>>>
>>> --
>>> Michael Fowler
>>> www.shoebox.net
>>
>> First off, thanks for all the patches, I've applied them all apart
>> from this one.
>>
>> And the main reason for that is deciding what is the best course of
>> action.
>>
>> ( I have no vested interest in POE::Component::Server::TCP myself
>> so can have a non-partisan view ).
>>
>> There is a difference between the documented behaviour and the actual
>> behaviour.
>>
>> I, personally, can't see the need to pass the socket object to the
>> ClientConnected handler, and without any evidence whatsoever to
>> substantiate my claim >:) I'd suggest that no one actually uses
>> the socket.
>>
>> ClientConnected would be used to send any initial text to the client
>> which one would usually use $_[HEAP]{client} for.
>>
>> Similarly, one might want to find out the TCP connection details,
>> which are again in the heap $_[HEAP]{remote_ip}, etc.
>>
>> My pennyworth.
>>
>> Anyways, I see three options:
>>
>> a). Make the functionality match the documentation;
>>
>> b). Make the documentation match the functionality;
>>
>> c). Do what dngor suggests and flatten ClientArgs, forget the socket
>>   and document as such.
>>
>> Cheers,
>>
>> --
>> Chris Williams
>> aka BinGOs
>> PGP ID 0x4658671F
>> http://www.gumbynet.org.uk
>> ==========================
>>