Downloading a file has the MIME type "application / x2x-download" - what is it?

Question

My Rails site allows users to upload documents, I use the attachment_fu plugin. I have a list of allowed content types [MIME] that I allow - standard image formats, Office documents, PDF, etc. I have a user who cannot download any PDF documents because the check is not performed looking in the logs. Attachment_fu considers the MIME type to be "application / x2x-download". User Browser - Firefox on Windows XP. When I try to download the PDF myself using Firefox on OS X or Safari or IE 6/7/8, it works fine. This seems to be just a problem with its browser.

I was looking for this type of MIME and does not seem to exist.

In theory, I could ignore the MIME type that the client reports and try to determine the file myself, perhaps by file -b --mime-type command, but that just seems sarcastic.

Another popular Rails plugin, Paperclip, does not perform MIME authentication itself, and also tries to trust the client’s browser.

What do you think? Ignore the client and [try] identify the download yourself, or try to find out why this user browser sets the completely invalid MIME type in the first place?

Answer 1

Many third-party applications can change the settings for the mime client type (I had my own adventure with the Amazon MP3 downloader application changing the mime types), so it is likely that your user has something similar (maybe something from x2x software ).

I would recommend sticking to mime / type as a means to convey what is and is invalid for your users, with secondary validation using ruby filemagic in validation.