CouchSurfer - CouchDB ORM

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Description

CouchSurfer is an extraction of CouchRest::Model from the excellent CouchRest gem by J. Chris Anderson. In addition, it provides association and validation methods.

Associations

CouchSurfer provides the following 4 association kinds:

• belongs_to
• has_many
• has_many :inline; and
• has_many :through

All association kinds take an optional :class_name option should you want your association to be named differently to the associated model.

class Page
  

The belongs_to associations accept two additional options - :view and query, enabling you to customise your associations to fit your needs. You must explicitly declare the view on the child model for associations to work

Example 1: basic

class User
  

Example 2: with options

class Account
  

Example 3: :inline

class User
  

Example 4: :through

class Account
  

Note on HasManyThrough

With reference to the above example, HasManyThrough works by retrieving all memberships associated with the account, collecting their ids and running a bulk retrieval on the Project.all view, which is implicitly created for all models and, as of 0.0.4, emits it's id (see CHANGELOG).

Caveats

• Sorting needs to be done client side
• The results do not contain any extra information that may be present on the ':through' model.

Validations

Validations, with the exception of validates_uniqueness_of, have been implemented using the Validatable gem.

Example

class Employee
  include CouchSurfer::Model
  include CouchSurfer::Associations
  include CouchSurfer::Validations

  key_accessor :email, :account_id
  belongs_to :account

  view_by :account_id, :email
  view_by :name

  validates_presence_of :name
  validates_format_of   :email, 
    :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i
  validates_length_of :postcode, :is => 7, :message => "not the correct length"

  # Will use the Employee.by_name view with {:key => employee_instance.name}
  validates_uniqueness_of :name

  # Uses a custom view and key for uniqueness within a specific scope
  validates_uniqueness_of :email,
      :view => :by_account_id_and_email,
      :query => lambda{ {:key => [account_id, email]} },
      :message => "The email address for this account is taken"

end

Please check out the specs as well :)

Next

• Error handling
• association methods with arguments: @account.projects(:limit => 2, :offset => 1)