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Use a Class's Method as the callback function for ob_start()

Posted on 2008-10-14
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Last Modified: 2012-05-05
How can I, or even may I, sue a class's method as the call back function for ob_start()?

I tried several ideas and googled, but nothing doing so far.

The output of the attached code returns:
--------------------------------------------------------------------------------------------
Hello World, and hello {testvar}
Goodbye World, and goodbye {testvar}
Hello World, and hello Beautiful
Goodbye World, and goodbye Ugly
--------------------------------------------------------------------------------------------

When I trying to get this result:
--------------------------------------------------------------------------------------------
Hello World, and hello Beautiful
Goodbye World, and goodbye Ugly
Hello World, and hello Beautiful
Goodbye World, and goodbye Ugly
--------------------------------------------------------------------------------------------

Thanks for the help!
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /><title>Buffer Testing</title></head>
 
<body>
<?php
class Testclass {
	public $testvar;
	public $html;
 
	public function Testclass() {
		$this->testvar="unknown";
		$this->html="helloworld.html";
	}
	
	public function displayOutput() {
		include($this->html);
	}
	
	public function adjustOutput($buffer){
		return (str_replace("{testvar}", $testvar, $buffer));
	}
	
}//END class Testclass
 
$ONE= new Testclass();
$TWO= new Testclass();
$ONE->testvar="Beautiful";
$ONE->html="helloworld.html";
$TWO->testvar="Ugly";
$TWO->html="goodbyeworld.html";
 
function cheatOne($buffer){
	return (str_replace("{testvar}", "Beautiful", $buffer));
}
function cheatTwo($buffer){
	return (str_replace("{testvar}", "Ugly", $buffer));
}
 
ob_start();//START MAIN BUFFER
 
  ob_start("$ONE->adjustOutput");//buffer one
    $ONE->displayOutput();
  ob_end_flush();
  
  ob_start("$TWO->adjustOutput");//buffer two
    $TWO->displayOutput();
  ob_end_flush();
 
  ob_start("cheatOne");//CHEATING buffer one
    $ONE->displayOutput();
  ob_end_flush();
  
  ob_start("cheatTwo");//CHEATING buffer two
    $TWO->displayOutput();
  ob_end_flush();
 
ob_end_flush();//OUTPUT THE MAIN BUFFER
 
?>
</body>
</html>

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Question by:dban00b
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4 Comments
 
LVL 1

Author Comment

by:dban00b
ID: 22716543
There's a typo in Testclass::adjustOutput()  "$testvar"  should read "$this->testvar" -- no change in the original question though, just didn't want anyone to get hung up on that typo.
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LVL 25

Accepted Solution

by:
Marcus Bointon earned 500 total points
ID: 22719629
This is a common thing. instead of providing the name of the function to call, you pass an array containing the instance and the function name, like this:

ob_start(array($ONE, 'adjustOutput');

Docs are here: http://www.php.net/manual/en/language.pseudo-types.php#language.types.callback
0
 
LVL 25

Expert Comment

by:Marcus Bointon
ID: 22719631
Oops, missed a bracket:

ob_start(array($ONE, 'adjustOutput'));
0
 
LVL 1

Author Comment

by:dban00b
ID: 22722001
Awesome!  Thanks!
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