Projectile

JSON model layer for RubyMotion applications. Inspired by Mantle.

Example

Using the classic blog example, where we have posts and comments, here's how you could define your subclasses:

class Post < Model
  set_attribute name: :id,
    type: :integer,
    key_path: "post.id"

  set_attribute name: :title,
    type: :string,
    default: "",
    key_path: "post.title"

  set_attribute name: :body,
   type: :string,
   default: "",
   key_path: "post.body"

  set_attribute name: :created_at,
    type: :date,
    key_path: "post.created_at"

  set_relationship name: :comments,
    class_name: :Comment,
    default: [],
    key_path: "post.comments"
end

class Comment < Model
  set_attribute name: :id,
    type: :integer,
    key_path: "comment.id"

  set_attribute name: :text,
    type: :string,
    default: "",
    key_path: "comment.text"
end

A Post has attributes id, title, body, created_at, and a to-many relationship to Comment. A Comment has attributes id and text.

Default values are set during object initialization. i.e, Model#new.

Key paths define where the values are located in a JSON Hash. This is so we know where the value exists during #new, and also helps us recreate the Hash in #to_hash.

Types

• integer
• float
• boolean
• date, only supports yyyy-MM-dd'T'HH:mm:ssZZZZZ right now.
• url, just turns the string into a NSURL
• string

Identity Map

To use an identity map, put these lines at the top of a class definition:

include IdentityMap
establish_identity_on :id

What this means:

1. Defines equivalence based on the id attribute
2. Holds all instances of class, keyed by id, in a class instance variable @@identity_map.

Use #merge_or_insert instead of #new from now on:

# this will either create a brand new post object, or merge with an existing one.
json = {
  "post" => {
    "id" => 1,
    "title" => "Hehehoho",
    "body" => "La Li Lu Le Lo",
    "created_at" => "2013-08-02T16:44:34-08:00"
  }
}
@post = Post.merge_or_insert json

You can use Post[1] to fetch the above object from anywhere. Kind of useful in the REPL.

Misc

I'm very open to ideas, please create issues, fork, whatever. Oh yeah, MIT.