#Collabda

Lets you build your models from JSON or YAML files.

class Food
  include Collabda
  source "app/data/foo.yaml", :type=>:yaml
  properties :name, :description
  attr_reader :name
end

Food.build_collection

It builds an array from your data so you can do Food.all to get all your food objects, or Food.map{|f| f.name} to get all the names.

Installation

You can just add gem collabda to your Gemfile or gem install collabda.

Source

Specifies which file to use for this class. The file should include an array of items, each of which will become an instance of your class.

Accepted types are :json and :yaml.

source "app/data/bar.json", :type => :json

Properties

A list of attributes which will be set as instance variables on your model.

properties :name, :url, :count

def name
  @name
end

Collabda doesn't add reader methods by default- it's left to you to add them. You could write methods which use the instance variables, or you could just use attr_reader.

attr_reader :count

def link(text)
  "<a href='#{@url}'>#{text}</a>'
end

Collections

Once you have set up your class, you should use YourClass.build_collection to build instances of your class from the loaded data. Calling this reloads data from the source path, and sets each an instance variable for each property.

Collection helper

You can use the Collabda.collection helper to build your classes automatically. It takes the capitalized name of your class as a symbol, and a block in which you define your class and its methods.

Collabda.collection(:Faq) do
  source "app/data/faqs.yaml", :type=>:yaml

  properties :question, :answer
  attr_reader :question, :answer
end

Its just shorthand for creating your class with class Faq, including Collabda, and calling Faq.build_collection after the class definition.

app/data/faqs.yaml

- question: Why is water wet?
  answer: The feeling of wetness is actually coldness
- question: Why don't all fish die when lightning hits the sea?
  answer: "The lightning spreads out because unlike air, water is a conductor"
- question: How do butterflies get inside your tummy?
  answer: Ruby Magic

You can go right ahead and use Faq.each do |faq| to loop over all your Q&As.

Rebuilding All Collections

As well as building an individual collection with YourModel.build_collection, you can get Collabda to rebuild all collections using Collabda.rebuild_collections. This is useful if you want to update all your Models after changing the files.

If you're using Rails, you can use the template in config/initializers/collabda.rb to auto-reload data in Rails' development mode.

Manual build

You can directly use YourClass.new(attributes_hash) if you need to create an instance which doesn't use the data file. This also registers the new instance as part of the collection, so it will appear in self.all.

All, Each & Enumerable

Collabda models implement Enumerable giving you all that sugary functional magic.

Collabda.collection :People do
  source 'app/data/people.yaml', :type => :yaml
  properties :name, :admin, :likes
end

Favourites include People.all, People.each, People.map, People.select and People.any?

Sorting & Filtering

You can use plain ruby methods from Enumerable to sort and filter your data. For example, the following will sort by likes descending:

def self.all
  super.sort{|a,b| b.likes <=> a.likes}
end

You can also create scopes using select:

def self.popular
  select{|p| p.likes > 300 }
end

def admin?
    @admin || false
end

def self.admins
  select{|p| p.admin? }
end

License

Copyright 2013 James Edwards-Jones

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.