Why is the attachment endpoint needed?

[quentez]

After filing issues #217, #218 and #219, I'm sort of wondering why is the attachment endpoint needed at all. It feels weird to have two different entry points to what is essentially the same thing. The post_attachment endpoint could return a file directly instead of redirecting to the attachment endpoint.

If a post needs to reference a specific attachment from another post, it could do so by specifying the post's id, version id, attachment name, and an optional content-type. This would have the added advantage of making it possible to reference an attachment without a specific content-type, leaving the negotiation up to the client using the Accept header. Something that isn't possible when referencing attachments directly with their digest. This could even be an extension of the links/deep-links that will be added in 0.4 (I don't know enough about them to know if this could be a use case or not).

I can understand that the attachment endpoint would have been needed in 0.3 to test whether a specific file was already uploaded, but I can imagine that searching posts by digest is something that will be allowed by complex queries in 0.4 (correct me if I'm assuming wrong here).