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Re: Output status during processing

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On Sun, 04 Nov 2012 13:52:35 -0800, Scott Johnson wrote:

> I could use AJAX to load the file and then process it in the background
> sending status points as it goes through AJAX.

Back up a step.

The server can't "send" status updates to the browser using ajax in the 
normal case, rather the browser would request "request" status updates 
from the server, usually in relation to some browser event (which might 
be a javascript timer timeout, or the user clicking a "get update" button 
or link).

Ajax, which is built on the http request / response, which is in turn 
built on a tcp/ip connection, is not a technology which generally allows 
the server to push unsolicited data to the browser, rather it is a 
technology that allows the browser to make requests to the server and 
receive data back without reloading the page being displayed.

Specifically, when you make an http request to a server, a tcp connection 
is opened to the server. The connection is usually closed after the 
server has sent the response. Making a connection to the server is easy, 
because tcp/ip knows that the server is listening to http on port 80. In 
the other direction, there is no official port that a browser listens out 
on for a server to make a connection to it, which makes it difficult for  
the server to open a connection to the browser to just send it something.

I know it may sound like a petty distinction to make, but making the 
distinction helps you keep it clear in your mind how it all fits 
together, and in the concept of php running behind a web-server, the 
context is generally servicing and responding to requests from the 
browser, not pushing data to the browser.

Rgds

Denis McMahon

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Thread

Output status during processing Scott Johnson <noonehome@chalupasworld.com> - 2012-11-04 11:23 -0800
  Re: Output status during processing "M. Strobel" <sorry_no_mail_here@nowhere.dee> - 2012-11-04 22:28 +0100
    Re: Output status during processing Scott Johnson <noonehome@chalupasworld.com> - 2012-11-04 13:52 -0800
      Re: Output status during processing Jerry Stuckle <jstucklex@attglobal.net> - 2012-11-04 20:21 -0500
        Re: Output status during processing Scott Johnson <noonehome@chalupasworld.com> - 2012-11-04 19:10 -0800
          Re: Output status during processing crankypuss <noemail@noemail.invalid> - 2012-11-05 07:24 -0700
      Re: Output status during processing Denis McMahon <denismfmcmahon@gmail.com> - 2012-11-05 12:40 +0000
        Re: Output status during processing Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-11-05 17:32 +0100
  Re: Output status during processing Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-11-05 14:22 +0100
    Re: Output status during processing Scott Johnson <noonehome@chalupasworld.com> - 2012-11-05 11:59 -0800
      Re: Output status during processing Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-11-06 00:21 +0100

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