Getting "php-images" to cache

[zikko]

Hell-o.

I know this issue has been addressed before in the forum, and I went through those threads briefly without finding anything that worked for me. Besides, this is not altogether the same thing.

I'm making a php application that handles images. The images are stored in files in a non-webserver-directory on the server for security reasons. I've made a simple php that fpassthru's it if the session is ok. Works the same with thumbnails and so on.

The thing is I would like these images - the thumbnails in particular - to be cached by the browser, since they are never
changed and are unneccesary to reload every time they are to be used.

This, it seems, it not easily done. I'm not even sure if it's possible, they are reloaded even if I set my browser cache settings to "Never" reload web content.

Is there any magic headers I can send to make the browser do what I want? I don't need it to work on every weird opera-or-whatever version, explorer 4+ will do fine.

/Thankful for help

[michael]

Caching control is done automatically on the client side.
You can override it with a meta tag, but would not want to do so since it overrides every element on the page.

I would create a iframe for the thumbnails presentation section, and put the cache control directive in that.

Otherwise, make do. =)

[blanius]

I actually did something similar with buttons generated from database.

Firstly you can just check if it exists and send the file if it does.

header('Content-Type: image/png');
    $path="/tmp/buttons";
    $text= $_GET['text'];

if ($bytes = @filesize("$path/$text.jpg")){
      header("Content-Length:$bytes");
     readfile("$path/$text.jpg");//send button
}else //make button

Or better you can use a custom 404 page that generates the button when there isn't one of the name called for.

This is covered in a very good book "programming PHP" by O'Reilly Press. The code I used for my site is just a slight variation on the code in that book.

The book at Amazon.com
http://www.amazon.com/exec/obidos/ASIN/1565926102/bretsplace/