Force download of attachment rather than opening it automatically

For the PDF only ..

// The user will receive a PDF to downloadheader('Content-type: application/pdf');// File will be called downloaded.pdfheader('Content-Disposition: attachment; filename="downloaded.pdf"');// The actual PDF file on the server is source.pdfreadfile('source.pdf');

...

for all other file type perhaps you could use .. echo mime_content_type('Yourfile.ext') o

header('Content-type: '.mime_content_type('Yourfile.ext'));header('Content-Disposition: attachment; filename="'.$output_filename.'"');readfile($source_filename);

Beware that I haven't tested it...

The Content-type header specifies what type of file is to be downloaded, specified by a mime type.The Content-Disposition header specifies a new filename for the file which is to be downloaded.The readfile line is not a header being sent, but a PHP call that gets all the data from a file and outputs it. The argument you pass to the readfile function is the location of the actual pdf file to be downloaded.

UPDATE

mime_content_type() function is deprecated. you'll ned to replace with this ...

$finfo = new finfo;$fileinfo = $finfo->file($file, FILEINFO_MIME);

you need to send the appropriate content-type headers().

Example (for pdf, but works for anything if you adjust the mimetype):

<?phpheader('Content-disposition: attachment; filename=huge_document.pdf');header('Content-type: application/pdf');   // make sure this is the correct mime-type for the filereadfile('huge_document.pdf');?> 

Additional reading:

http://webdesign.about.com/od/php/ht/force_download.htm

Using the answer kindly provided by @HappyApe, here is the full code that I use to achieve forcing download of a document when clicking on an attachment link in Wordpress.

/** * Check that a page is the permalink of an attachment and force the download of the attahment if it is */add_action('template_redirect', 'template_redirect');function template_redirect(){    global $post;    /** Get the attachment URL as a pertty link ($url) and as a link to the file ($guid) */    $url = get_permalink($post->ID);    $guid = wp_get_attachment_url($post->ID);    /** Get the file name of the attachment to output in the header */    $file_name = basename(get_attached_file($post->ID));    /** Get the location of the file on the server */    $file_location = $_SERVER['DOCUMENT_ROOT'].substr($guid, strpos($guid, '/wp-content'));    /** Get the file Mime Type */    $finfo = new finfo;    $mime_type = $finfo->file($file_location, FILEINFO_MIME);    /** Check that the page we are on is a local attachment and force download if it is */    if(is_local_attachment($url)) :        header("Content-type: ".$mime_type, true, 200);        header("Content-Disposition: attachment; filename=".$file_name);        header("Pragma: no-cache");        header("Expires: 0");        readfile($guid);         exit();    endif;}