Re: [PHP] Re: Periodic Actions in PHP?

On Jun 13, 2009, at 9:11, Colin Guthrie <[email protected]> wrote:

> 'Twas brillig, and Parham Doustdar at 13/06/09 09:42 did gyre and  
> gimble:
>> Hi there, I'm going to create a small chat script with PHP. The
>> messages you want others to see will be added to a flat file (I.E.
>> TXT file), and read and displayed by PHP. However, I want this
>> reading and displaying to be periodic. This means that I want PHP to
>> check the file for new lines every,say, fifteen seconds. How may I do
>> that? I have been unable to find any function that acts like a timer.
> For handling periodic tasks in a web environement, I use a little
> persistent object (stored using APC) that has it's "process()" method
> called on every request. Internally it knows when it was last run and
> will actually only do work in it's process() method if it's not been
> called for a while.
>
> When this work is done, the user's request is obviously slowed down
> slightly, but not in a noticeable way.
>
> If you don't need something this self contained, then a normal cron  
> job is needed.
>
>
> All that asside, I'm not sure you're asking the right question. If  
> you've got a chat system, then the client side is presumable a web  
> server. You can't really push information from the server side to  
> the client, so you really need to pull it from the client side.  
> Usually you'd have a javascript timeout that submits an ajax request  
> to the server and displays any new messages to the user. In this  
> case, PHP doesn't need to be timed, the client is pulling  
> periodically so it's the client that sets the timer.
>
> Col
>
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>
> Colin Guthrie
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> http://colin.guthr.ie/
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If the goal was to push data, the OP could investigate the use of a  
comet server. It holds a long running stream allowing the server to  
push new data to the client.

Bastien