缓存由PHP脚本生成的图像

Question

Well, as given in the title, I want to cache the resource generated by my php script on the user's browser. I want to do so because I want to serve thumbnail images for some images from the server side dynamically. I have this .htaccess file with these contents in it.

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule ^(.+)$ index.php?image_id=$1 [QSA,L]

And index.php file contains these codes.

<?php

      header('Last-Modified: ' .gmdate('D, d M Y H:i:s',time()-3600) . ' GMT');


$image_id=$_GET['image_id'];
$chunk=  explode("/", $image_id);
$destination_height=$chunk[0];
$destination_width=$chunk[1];
$image=$chunk[2];
if(file_exists($image))
{
$extension=explode(".",$image);
$extension=end($extension);
switch ($extension) {
    case "jpg":
        $source_image=  imagecreatefromjpeg($image);
        break;
case "jpeg":
        $source_image=  imagecreatefromjpeg($image);
        break;
    case "gif":
        $source_image=  imagecreatefromgif($image);
        break;
    case "png":
        $source_image=  imagecreatefrompng($image);
        break;    
    default:
        break;
}
        $source_height = imagesy($source_image);
        $source_width = imagesx($source_image);
        if($destination_height=="full")
        {
            $destination_height=$source_height;
        }
        if($destination_width=="full")
        {
            $destination_width=$source_width;
        }
        $destination_image=  imagecreatetruecolor($destination_width, $destination_height);
  $dst_x=0;
     $dst_y=0;
     $src_x=0;
  $src_y=0;
  imagecopyresized($destination_image,$source_image,$dst_x,$dst_y,$src_x,$src_y,$destination_width,$destination_height,$source_width,$source_height);
switch ($extension) {
    case "jpg":
   imagejpeg($destination_image);
   header("content-type:image/jpeg");
        break;
  case "jpeg":
   header("content-type:image/jpeg");
   imagejpeg($destination_image);
        break;
    case "gif":
   header("content-type:image/gif");
   imagegif($destination_image);
        break;
    case "png":
   header("content-type:image/png");
   imagepng($destination_image);
        break;
    default:
    break;
}
}
?>

Even after this when I go to developer mode and see the network tab on google chrome, the status information is : 200 OK
What can be done to cache all the images generated by this script? Because for a particular url, in this implementation, the content is never changed, so I want to cache the images. Any sort of ideas will be appreciated. Thanks.

Answer 1

use this

file_put_contents($filename, $imagedata);

It will write the image to the server and since your htaccess file will only run the image generating if the file doesn't exist it will only write files once and then serve the cached versions from then on.