So here are two examples, they are in my web tree, but you can see the process.
Real locations are:
/i/12t.jpg
/images/10t.jpg
Fake locations are:
/external/image-wrapper/image/12t.jpg
/external/image-wrapper/i/10t.jpg
Please note I am explaining little bits. You will have to download entire code to get this working. It’s well commented.
Step 1: Routing
Route all files through your image wrapper script. This is done with the magic of .htaccess . I am not going to explain it, as many people have done it better, but basically it just takes a request and sends it to my index.php file
grab source: htaccess.txt
Step 2: Parse URL
Basically we grab the requested URL
//parse url into parts
$parts = @parse_url($_SERVER['REQUEST_URI']);
Next we grab the image path
## GRAB IMAGE PATH
$web_path = '/external/image-wrapper/';
// drop multiple slashes
$uri_path = preg_replace('#/+#', '/', $parts['path']);
// drop trailing slashes
$uri_path = preg_replace('#/$#', '', $uri_path);
// drop site path
$path = trim(preg_replace('#^'.$web_path.'#', '', $uri_path));
This takes this “/external/image-wrapper/i/10t.jpg” and just makes is “i/10t.jpg”;
Step 3: Send correct place
There are probably many ways to this, but basically i set up an array of regular expressions and see what it matches and send correct place.
//image handlers
$pages = Array(
//( /i/image_name)
'#^i/([^/]+)$#' => 'do_image',
//-------------
//( /image/image_name)
'#^image/([^/]+)$#' => 'do_image_other'
);
foreach ($pages as $page_pattern => $the_func)
{
if (preg_match($page_pattern, $path, $matches))
{
//call function
$the_func();
break;
}
}
Step 4: Check image
//get info about image
$image_info = pathinfo($img_dir.$img_name);
//has name
!empty($img_name)
//has extension
@isset($image_info['extension']) &&
//has basename
@isset($image_info['basename']) &&
//valid extension
isset( $ext_list[ strtolower( $image_info['extension'] ) ] ) &&
//real file
file_exists($img_dir.$image_info['basename'] )
Step 5: Send image
//set correct header
$contentType = 'Content-type: '.$ext_list[ $image_info['extension'] ];
header ($contentType);
//send file to browser
readfile($img_dir.$image_info['basename']);
exit(0);
Usage
As mentioned i used this to get around images not being in the web tree, but there are other things you could do
- Get around image not being in web tree
- Increment counter to see how many times images is requested
- Add identifying information with GD
- more?