php redirect + force download

I am creating a google-chrome application that will download songs from an octet stream, however due to JavaScript restrictions, I cannot create a "download" button. The user must right click and select save file as. I wish to create a php page that will redirect the browser to the location of the octet stream, which will be on a different site, and then create a download dialog there. I know there are probably security restrictions here, but is it possible to have a php page redirect and set the content disposition headers of that page it is redirecting to?

Note: I cannot get the octet stream from my server to save because the host I am using does not support php calls to external sites.

The download dialog (content-disposition header) has to be produced by the other site. There's no way around it, because browsers will only believe headers from the same server. If the other site doesn't produce the desired headers, and if you don't own the other site, there's nothing you can do about it.

You might write a PHP script which accesses the other site on behalf of the user, downloads the octet stream to the server first, and then sends it to the user with the desired headers. In other words, your script would act as a proxy server. Look into the curl module if interested. But this will cause your server's bandwidth to skyrocket, and there may also be problems with copyright.