Support arrays of links with JSON HAL

[acrispino]

JSON HAL spec (http://tools.ietf.org/html/draft-kelly-json-hal-03#section-4.1.1) says,

[_links] is an object whose property names are link relation types (as defined by [RFC5988]) and values are either a Link Object or an array of Link Objects.

Mike Kelly gives an example of what that looks like (https://groups.google.com/group/hal-discuss/msg/5afa41ab1740aee1):

{ 
 "_links": { 
   "self": { "href": "/product/987" }, 
   "upsell": [ 
     { "href": "/product/452", "name": "FP01", "title": "Flower pot" }, 
     { "href": "/product/832", "name": "HD77", "title": "Hover donkey" } 
   ] 
}

Presently, if you try to use an array of links, the output is more like:

{ 
  "_links": { 
    "self": { "href": "/product/987" }, 
    "upsell": {
      "href": [ "/product/452", "/product/832" ]
    }
  }
}

[apotonick]

Oh I was hoping this is a pull request ;-)

[apotonick]

So, to have links we currently have the following mechanics.

link :self do
  product_url(self)
end

link :rel => :self, :title => "Myself" do
  product_url(self)
end

I'd love to have the following.

link :self do
  {:title => full_title, :href => ..}
end

Here, you can return a hash where the block itself is executed in instance context, meaning you can access attributes of the represented object at runtime (like #full_title).

link :self, :array => true do
  [ {:title => full_title, :href => ..},
    ..
  ]
end

When :array => true is set, the link will be an array of LinkObjects following the HAL specification.

[dnd]

Has the format

link :self do
  {:title => full_title, :href => ..}
end

been implemented yet? It sort of works, but I get the links nested under an href key:

"self":{
  "href":{
    "title":"Awesome generated name",
    "href":"/reports/20121025161822"
  }
}

I need to be able to access a method on the model to determine the proper title to display, and I can't do that by passing a hash to the link method itself.

[apotonick]

Since this years' conference season is over for me I finally have time to code! Expect all of the upper behaviour in less than a week :-)

[locks]

sorry to ping you again about this, but it's a sticking point in my API

[apotonick]

Implemented in 0.11.5: http://nicksda.apotomo.de/2013/01/released-roar-0-11-5-with-hal-link-arrays-and-representable-1-2-9-with-polymorphism-support/

[locks]

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