scam(2) - Really basic fake models for in-memory types

scam(2)
Scam Manual
scam(2)

NAME

scam - Really basic fake models for in-memory types

SYNOPSIS

Write your model class. Mix Scam in via include Scam. Go eat a sandwich.

ScamModel.create(attrs={})
ScamModel.find(id_or_attributes)
ScamModel.sorted_by(attribute)
ScamModel.all
ScamModel[id]
ScamModel#==(object)
ScamModel#eq?(object)

DESCRIPTION

Scam is a small mixin for making a class look like an ORM-ish object, ala ActiveRecord, MongoMapper, etc. Classes including Scam get a create method for creating new instances, find and [] accessors for looking them up, enumerable methods (select, reject, etc.) for querying for in-memory models, can define a sort order, and methods for comparing instances.

USAGE

Include the Scam module into your class. This will automatically add an id attribute and accessor to your class.

CREATING MODELS

You can make a new model instance by calling create on your class. This method takes a hash specifying the value for all the attributes on the class. At the least, you should pass an id value; otherwise, what's the point?

LOOKING UP MODELS

Once you've created some models, you can look them up with find or []. They both take either a number or a string as a parameter and look up model objects by ID. If a model could not be found for the specified ID, nil is returned.

SORTING MODELS

Usually you'll want to sort models by ID; indeed this is the default ordering. However, should you come across a case where you want models to order by some other attribute, you can specify it with sorted_by, passing the attribute to sort on.

LISTING ALL MODELS

Should you need to fetch all the models defined in memory, you can fetch them with all. This will return an array of all models created so far.

COMPARING MODELS

Given two model instances, you can compare them for equality with == or eql?. They both return true if the instances have the same class and ID; otherwise, they return false.

ERRORS AND EXCEPTIONS

No exceptions are raised by Scam methods. Enumerable methods (select, detect, etc.) will return nil if nothing was found.

EXAMPLE

class FeedTemplate
  include Scam

  sorted_by :title
  attr_accessor :title
end

FeedTemplate.create(:id => 1, :title => 'Twitter')
FeedTemplate.create(:id => 2, :title => 'Dribble')

FeedTemplate.all

FeedTemplate.each do |tpl|
  # Tinker with tpl
end

FeedTemplate.detect { |tpl| tpl.title == 'Twitter' }

FeedTemplate.find(2)

FeedTemplate.find('2')