PHP Image content type problem

Question

I have a specific problem, and cant get over it.

For my latest project I need a simple PHP script that display an image according to its ID sent through URL. Here's the code:

header("Content-type: image/jpeg");
$img = $_GET["img"];
echo  file_get_contents("http://www.somesite.hr/images/$img");

The problem is that the image doesn't show although the browser recognizes it (i can see it in the page title), instead I get the image URL printed out.

It doesn't work neither on a server with remote access allowed nor with one without. Also, nothing is printed or echoed before the header.

I wonder if it is a content type error, or something else. Thanks in advance.

Solution 1

Possibly the image doesn't fit into memory. Or your PHP installation doesn't have permissions to make external HTTP calls. Anyway, I suggest you never use echo file_get_contents(), use readfile instead. Also you should never use raw strings from $_GET or $_POST for file operations. Always strip null-bytes, slashes and double dots from user-provided filenames, or better yet, allow only alphanumeric characters.

Solution 2

I was doing something like this recently, but found this a slow method (I was doing 15+ on a page). This is slow because first your server has to download the image, and then send it to the client. This means for every image it is downloaded twice.

I came up with an alternative - redirection. This allowed the client machines to directly access the other site while hiding the real url in the HTML source code.

$r - is processed above the script, and validated to make sure it is ok.

$webFile = 'http://www.somesite.com/'.$r['type'].'/'.$r['productid'].'.jpg';
header('Location: '.$webFile);
exit();

Granted if someone put my image url in the address bar, it would redirect and the user would see the real url, but it made my page faster and I wasn't too worried about that.

Solution 3

You'll want to ensure that your script is not outputting any white-space. Check before and after the opening/closing PHP tags.

If that checks out, you'll want to ensure that allow_url_fopen is set to On in php.ini

Comments

[zod]

you want to show the image on browser or download the image?

[ahmet alp balkan]

make sure that echo works. try to fetch that page with curl or wget. and make sure that no preceeding whitespace exists before echoing.

[Mirko]

I resolved the first two problems, it really was a whitespace and a code error, but I still got the remote access issue, so I'm forced to use CURL. Can u help me with that, cos I'm not so good with CURL?

[Mirko]

The image is very small and this is just a testing script. I agree with you in using readfile and for the other tips, but i already tried readfile and doesn't work neither.

[Mirko]

I managed to get here, but in a strange way when i send the image ID it doesn't work, it doesn't display the image. Instead when I click on the image source I get the message "The document has moved".