How to Buffer Output Data in PHP With ob_start Method

1. Buffer Simple String Using the ob_start Method Then Get Data Using the ob_get_contents Method in PHP
2. Buffer HTML Data Using the ob_start Method and Get Data Using the ob_get_contents Method in PHP
3. Buffer String Data and Replace Chars in the String Using the ob_start Method With a Callback Function

We will initialize a buffer with the ob_start method and then output a simple string which will be automatically buffered; we will then get the data from the buffer with the ob_get_contents method and then print it.

We will also initialize a buffer ob_start method and then output an HTML block which will be automatically buffered; we will then get the data from the buffer with the ob_get_contents method and then print it.

Lastly, we will initialize a buffer ob_start method, declare a simple string that will be automatically buffered, and then replace data in the string using a call back passed to the ob_start method.

Buffer Simple String Using the ob_start Method Then Get Data Using the ob_get_contents Method in PHP

We will set ob_start and then output a simple string automatically buffered; we will then get the data from the buffer using ob_get_contents and print it.

<?php
ob_start();
echo("Hello there!"); //would normally get printed to the screen/output to browser
$output = ob_get_contents();
echo $output;
?>

Output:

Hello there! Hello there! 

Buffer HTML Data Using the ob_start Method and Get Data Using the ob_get_contents Method in PHP

We will set ob_start and then output HTML data automatically buffered; we will then print the buffered data.

<?php
ob_start();
?>
<div>
    <span>text</span>
    <a href="#">link</a>
</div>
<?php
$content = ob_get_contents();
?>

Output:

<div>
 <span>text</span>
 <a href="#">link</a>
</div>

Buffer String Data and Replace Chars in the String Using the ob_start Method With a Callback Function

We will set ob_start and then output HTML data automatically buffered; we will then print the buffered data.

<?php
    //Declare a string variable
    $str = "I like PHP programming. ";
    echo "The original string: $str";

    //Define the callback function
    function callback($buffer)
    {
    //Replace the word 'PHP' with 'Python'
    return (str_replace("PHP", "Python", $buffer));
    }

    echo "The replaced string: ";
    //call the ob_start() function with callback function
    ob_start("callback");

    echo $str;
?>

Output:

The original string: I like PHP programming. The replaced string: I like Python programming.