Problems With Forcing Download of a PDF File

Question

I have the following function to force download a file:

static public function download($file, $options=array()) {
    $content = (isset($options['content'])) ? $options['content'] : '';
    $contentType = (isset($options['contentType'])) ? $options['contentType'] : '';
    header('Cache-Control: public');
    header('Content-Description: File Transfer');
    header('Content-Disposition: attachment; filename='.File::filename($file));
    header('Content-Type: '.$contentType);
    header('Content-Transfer-Encoding: binary');
    if ($content!='') {
        echo $content;
    } else {
        readfile($file);
    }
}

i send a PDF file and contentType = "application/pdf". the problem is that when i try to open the downloaded PDF file it says "There was an error opening this document. The file may be corrupt". Is weird because i can open the original file and they look exactly the same (filename, size, etc)

Answer 1

Ensure there is no output before this function is ran, and for good measure, use the exit construct at the end of this function :)