wprater / projectile

thin layer to make json models easier to work with on a typical ios rest-client app written in rubymotion

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.