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Comment by jaytaph | Hacker News Reader

I think some of the articles actually talk about json-hal and ld. Not sure about schema.

The examples are in XML because json is, (and I believe at this point), still not stricly an (accepted) hypermedia capable format, thus not adhering the HATEOAS constraint, and thus cannot be restful. But to be honest, I'd prefer JSON over XML anytime.

Please, if you have any idea's on how to improve the site, the whole idea was to set up a small set of articles which others could help out expanding. It turned out that not many people actually posted their idea's (or even complete posts), so what you see on the site is pretty much the same thing as 2-3 years ago. I'd love some more PR's on expanding with up-to-date technologies and techniques (even those who aren't truly restful)

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> The examples are in XML because json is, (and I believe at this point), still not stricly an (accepted) hypermedia capable format, thus not adhering the HATEOAS constraint, and thus cannot be restful. But to be honest, I'd prefer JSON over XML anytime.

What exactly is the criteria of being a "hypermedia capable format"?

The linked website gives an example of how the response on a bank-account like API might include links to other actions; XML and JSON seem equally capable here, as they can both encode links.

He mentions on another page,

> Unfortunately, JSON is not a hypermedia format. There is no predefined way to deal with link discovery in JSON.

Is there a predefined way to deal with it in XML? In the earlier example, I had assumed he did exactly what you would do in JSON: make up a field for the purpose.

Though, honestly, that would seem to be the purpose of the "Link:" header.

> What exactly is the criteria of being a "hypermedia capable format"?

One document must be able to link to another.

> Is there a predefined way to deal with it in XML?

Yes, Xlink:

http://www.w3.org/TR/xlink11/

> In the earlier example, I had assumed he did exactly what you would do in JSON: make up a field for the purpose.

The problem with this is that it's non-standard and nothing understands it that isn't custom-written for that particular API.

> Though, honestly, that would seem to be the purpose of the "Link:" header.

Yes and no. Although the Link header is useful, it's not part of the document, it's a transport layer header. REST is transport-layer neutral.

There are a number of specifications that address linking in JSON:

  * JSON-LD http://www.w3.org/TR/json-ld/
  * HAL https://tools.ietf.org/html/draft-kelly-json-hal-06
  * Siren https://github.com/kevinswiber/siren
  * Uber https://rawgit.com/uber-hypermedia/specification/master/uber-hypermedia.html

Totally agree on the points against making up a field / format. Using standards where you can is a great way to bring familiarity & common tooling into your APIs. But don't focus too much on XML vs. JSON, use what you need / want, you can find a standard to support it.

HAL solves this issue pretty well, doesn't it?

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