YAML mime type?

Question

What is the most appropriate MIME type to use when sending data structured with YAML over HTTP?

An explanation of why a given choice is most appropriate would be much appreciated.

There is no registered application type or text type that I can see.

Example:

> GET /example.yaml

< Content-Type: ????
<
< --- # Favorite movies
< - Casablanca
< - North by Northwest
< - Notorious

Possible options:

text/yaml
text/x-yaml
application/yaml
application/x-yaml

Answer 1

http://dev.rubyonrails.org/svn/rails/trunk/actionpack/lib/action_controller/mime_types.rb

Ruby on Rails uses application/x-yaml with an alternative of text/yaml.

I think it's just a matter of convention, there is no technical why, afaict.

Answer 2

I'd say text/x-yaml:

text over application because it's a human-readable

x-yaml over yaml because it hasn't been accepted into the registered list of mime types.

Edit: from RFC 3023 (XML Media Types):

The top-level media type "text" has some restrictions on MIME entities and they are described in [RFC2045] and [RFC2046]. In particular, the UTF-16 family, UCS-4, and UTF-32 are not allowed (except over HTTP[RFC2616], which uses a MIME-like mechanism).

Interesting... Not exactly sure what it means, but food for thought.

Answer 3

I know this is ugly, but use text/plain if you want to display it in a browser and have it formatted correctly - all of the above will default to a download in IE or Firefox.

Answer 4

"x-" media types are discouraged, see RFC 4288, Section 3.4. The right thing to do is to use the personal tree, the vendor tree, or to actually attempt a proper media type registration.