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by rhizome31 4543 days ago
Thank you and Steve for your replies.

You both seem to recommend HAL over other Hypermedia formats. In their book, Richardson & Amundsen mention that HAL doesn't allow to tell the client which HTTP methods to use when doing state transitions. They say that HAL is therefore only suited for read-only APIs. What do you think of that?
2 comments
darrelmiller 4543 days ago
Link relations can be designed that indicate which HTTP methods are allowed. HAL is heavily dependent on conveying semantics via link relations, which is something that some people don't like doing.

Consider the oauth2-token link relation defined here[1]. The definition of this link relation refers to RFC 6749 [2] which states that it is necessary to pass a application/x-www-form-urlencoded body using POST.

[1] https://tools.ietf.org/html/draft-wmills-oauth-lrdd-07#secti... [2] https://tools.ietf.org/html/rfc6749#section-4.1.3

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gamache 4542 days ago
Formally, they're absolutely right. Information like that is out of band with HAL.

In practice, I deal with it by sticking to HTTP verb conventions and specifying what to do in the documentation.

It's not automatic -- it'd be e.g. rsrc.somelink.post(params) instead of rsrc.somelink(params) in HyperResource's case -- but it works, and any human who knows what the 'somelink' rel is supposed to do might also be expected to know how to use it.

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