ob_start();
echo 'some_output';
$content = ob_get_contents();
ob_end_clean();

echo 'Content generated :'.$content;

$cache_filename = basename($_SERVER['PHP_SELF']) . "?" . $_SERVER['QUERY_STRING'];
$cache_limit_in_mins = 60 * 32; // this forms 32hrs
// check if we have a cached file already
if ( file_exists($cache_filename) )
{
    $secs_in_min = 60;
    $diff_in_secs = (time() - ($secs_in_min * $cache_limit_in_mins)) - filemtime($cache_filename);
    // check if the cached file is older than our limit
    if ( $diff_in_secs < 0 )
    {
        // it isn't, so display it to the user and stop
        print file_get_contents($cache_filename);
        exit();
    }
}

// create an array to hold your HTML output, this is where you generate your HTML
$output = array();
$output[] = '<table>';
$output[] = '<tr>';
// etc

//  Save the output as manual cache
$file = fopen ( $cache_filename, 'w' );
fwrite ( $file, implode($output_final,'') );
fclose ( $file );

print implode($output_final,'');

<?php
header("HTTP/1.1 200 OK");
//header("Content-Type: application/json");
header("Content-Encoding: gzip");

$cache_filename = basename($_SERVER['PHP_SELF']) . "?" . $_SERVER['QUERY_STRING'];
$cache_filename = "./cache/".md5($cache_filename);
$cache_limit_in_mins = 60 * 60; // It's one hour


if (file_exists($cache_filename))
{
    $secs_in_min = 60;
    $diff_in_secs = (time() - ($secs_in_min * $cache_limit_in_mins)) - filemtime($cache_filename);
    if ( $diff_in_secs < 0 )
    {
        print file_get_contents($cache_filename);
        exit();
    }
}
ob_start("ob_gzhandler");
?>

<?php
$content = ob_get_contents();
ob_end_clean();
$file = fopen ( $cache_filename, 'w' );
fwrite ( $file, $content );
fclose ( $file );
echo gzencode($content);
?>

<?php
include "cache_start.php";
echo "Hello Compress Cache World!";
include "cache_end.php";
?>