PHP echo-ing content as page loads

Question

So I'm doing some experimenting with PHP/Apache. Let's say I have this code.

<div>DIV 1</div>
<?php sleep(2); ?>
<div>DIV 2</div>
<?php sleep(2); ?>
<div>DIV 3</div>
<?php sleep(2); ?>
<div>DIV 4</div>
<?php sleep(2); ?>

For some reason on my local apache webserver all the data appears in the browser at once, after all 4 sleep()s have been executed (8 seconds).

However if I run it on my host's server, the data is echo-ed to the browser in real time. As in... div1 appears, after 2 seconds div 2 appears etc.

Why is that? Is this some setting in Apache?

It's buffering and caching through several layers and devices, which you cannot and should not attempt to control to any large degree of certainty. — Lightness Races in Orbit, Jun 18 '11 at 14:39

score 6 · Accepted Answer · edited Jun 18 '11 at 14:58

6

No it may be a setting in php.

In you local server, output_buffering is enabled in your php.ini file.

You can disable it by setting :

output_buffering = off

To Ensure that the content is sent to the browser each time a echo-like statement is used, add :

implicit_flush = on

You also can set the buffer size by giving output_buffering a value.

output_buffering = 4096

here the buffer size would be 4KB.

Output buffering tells php to keep in memory all data to be sent to the browser until it encouters a flush() instruction in your code, the buffer happens to be full, or it is the end of the script.

Here is the full reference for output buffer from php.net : php output buffer

edited Jun 18 '11 at 14:58

Sebastian Paaske Tørholm

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answered Jun 18 '11 at 14:22

dader

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oh sorry, my english ! I meant 4KB. – dader Jun 18 '11 at 14:45
You were right output buffering was on. I disabled it but it still does the same. Any other ideas? – John Jun 18 '11 at 14:47
1

just to double-check, is apache restarted ? – dader Jun 18 '11 at 14:48
if you phpinfo() what does it tell you about the option ? – dader Jun 18 '11 at 14:49
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you may need to add "implicit_flush = on" in your php.ini – dader Jun 18 '11 at 14:55
That did the trick, thanks! Weird thing though, I checked my host's phpinfo() and they have implicit_flush = off but it still works. – John Jun 18 '11 at 15:09

PHP echo-ing content as page loads

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