Re: RE: [PHP] flushing AJAX scripts

2009-03-27 Thread jim white
Well, the point was that I had tried the first way, submitting one AJAX 
request and waiting for it to finish and it was timing out, probably on 
my firewall which it shouldn't have - but it did. The reports can take 
10 seconds or 10 minutes to create. Doing it this way I can still load 
the report even if the original request shuts down after 3-4 minutes.


Jim

Andrea Giammarchi wrote:
Sorry Jim, I meant Jim when I wrote Kim ... and 
Phico: http://webreflection.blogspot.com/2008/04/phomet-changes-name-so-welcome-phico.html


Regards

  

From: an_...@hotmail.com
To: php-general@lists.php.net
Date: Fri, 27 Mar 2009 15:55:28 +0100
Subject: RE: [PHP] flushing AJAX scripts


Sorry, Kim, but why on earth you are polling with a second request to know when 
the first one has finished?
I mean, when the first request inserts data in the database that's it, you'll 
manage the end of the request.

$A --->  do stuff; do stuff; do stuff; report ready;
$B ---> report ready?
$B ---> report ready?
$B ---> report ready?
$B ---> report ready?
report ready; ---> notification to A
$B ---> report ready;

the report ready, if it is when $A request has been finished, will be in $A, 
the polling via $B is absolutely useless, imo.

There is no timeout from Ajax, it simply keep waiting, but obviously if your 
PHP has max_execution_time 30 seconds and the script execution takes more than 
30 seconds there's no polling that could save you.

The same if the user closes the browser, connection lost, bye bye response.

To have a notice, you need Comet, try out Phico but still, a page that requires 
that much is not suitable for the web. Report creation should be a cronjob in a 
separed thread if it is that stressful.

Regards



Date: Fri, 27 Mar 2009 10:47:10 -0400
From: jbw2...@earthlink.net
To: an_...@hotmail.com
CC: php-general@lists.php.net
Subject: Re: RE: [PHP] flushing AJAX scripts

My page submits the AJAX request to complete a report that takes some 
time, and upon completion stores results in a database. A second AJAX 
request polls every 5 seconds and queries the database if the report is 
ready. This hopefully will get around any timeout problems I am having 
with a long running request, and seems to be working. It looks like I 
can accept the default behavior for now. I don't depend on getting a 
response from the original request, but is there a point where the AJAX 
response script will be stopped either by Apache or PHP before it can 
insert into the database?


Jim
  

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Re: RE: [PHP] flushing AJAX scripts

2009-03-27 Thread jim white
My page submits the AJAX request to complete a report that takes some 
time, and upon completion stores results in a database. A second AJAX 
request polls every 5 seconds and queries the database if the report is 
ready. This hopefully will get around any timeout problems I am having 
with a long running request, and seems to be working. It looks like I 
can accept the default behavior for now. I don't depend on getting a 
response from the original request, but is there a point where the AJAX 
response script will be stopped either by Apache or PHP before it can 
insert into the database?


Jim


Andrea Giammarchi wrote:

Some browser would like to receive at list N characters (bytes) even if
you force the flush, before the browser will show those characters.
In
any case, the Ajax request will not be completed until its readyState
will be 4, which means the page execution on the server has finished
(released, php has gone, flush or not flush)
For a task like this one you have few options:
 1 - launch  new thread if your host is able to do it
 2 - use a Comet like response (for php I wrote Phico some while ago)
In any case, I hope this stressful operation cannot be performed from thousand 
of users or you can say bye bye to the service.
Alternatives:
 1 - optimize your database
 2 - delegate the job once a time rather than every click (cronjob)
 3 - if the bottleneck is PHP, create an extension in C to perform the same task

Hope this help.

Regards

P.S.
Internet Explorer a part, you can read the responseText on readystate 3
which will be called different time (most likely for each flush).
If IE is not your target, you could consider this opportunity to read the sent 
stream so far.

  

Date: Fri, 27 Mar 2009 08:49:35 +1100
From: dmag...@gmail.com
To: jbw2...@earthlink.net
CC: php-general@lists.php.net
Subject: Re: [PHP] flushing AJAX scripts

jim white wrote:

I am using jQuery AJAX request to run a script that can take several 
minutes to create a report. I want to start the script and immediately 
echo a response to close the connection and then let the script complete 
a report which I can get later. I have tried several thing such as


ob_start();
echo json_encode(array("time"=>$now, "message"=>"Report has started 
running!"));

ob_end_flush();
  

Try something like this

echo "something";
flush();

without the ob* stuff.

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