How can i improve this?

PHP Code:

---

<?php

if (isset ($_GET) and !empty ($_GET))
{
    if (!isset ($_GET['file']) and empty ($_GET['file']))
    {
        trigger_error ("File needed!");
    }
    if (!isset ($_GET['type']) and empty ($_GET['type']))
    {
        trigger_error ("Type needed!");
    }
    $file = $_GET['file'];
    $type = $_GET['type'];
    switch ($type)
    {
        case "css":
            header ("Content-type: text/css");
        break;
        case "js":
            header ("Content-type: text/javascript");
        break;
        case "img":
            if (!isset ($_GET['img']) and empty ($_GET['img']))
            {
                trigger_error ("Image type needed!");
            }
            $img = $_GET['img'];
            switch ($img)
            {
                case "png":
                    header ("Content-type: image/png");
                break;
                case "gif":
                    header ("Content-type: image/gif");
                break;
            }
        break;
    }
    echo file_get_contents ($file);
}

?>

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Anyway to improve this?
It works fine for what i want it to do but I'm sure there's way to improve it.

Thanks.

Line 3 is pretty much useless because if $_GET['file'] or $_GET['type'] are set, it will always go into the if statement.
Defining $file, $type and $img is not necessary as you only use it once, just use the $_GET['file/type/img'] variable directly.
Line 28 to 37 can be changed to 1 line with the ternary operator.
Line 40 could be dangerous as you do not check if the file exists and is in the right directory. (LFI/RFI).

edit: nvm about that previous shit.

i'd do this:

PHP Code:

---

$allowed_types = array("text/css", "text/javascript", "image/png", "image/gif");

if(isset($_GET['file'])) {
    if(in_array($_GET['type'], $allowed_types)) {
        header("Content-type: ". $_GET['type']);
        echo file_get_contents($_GET['file']);
    } else {
        trigger_error("Invalid type specified!");
    }
} else {
    trigger_error("File needed!");
} 


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keep in mind you'd have to change the $_GET values you're sending a long a bit...

May I suggest a more data-driven approach? Without error handling code you could make it clean and maintable as:

PHP Code:

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$image_types = array("png" => "png", "gif" => "gif");
$text_types = array("css" => "css", "js" => "javascript");

$type = $_GET['type'];
$img = $_GET['img'];

$content_type = ($type == "img") ? "image/" . $image_types[$img] : "text/" . $text_types[$type];

echo "Content-type: $content_type"; 


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