A glorified before_filter that loads an instance of an
ActiveRecord object as the result of searching for said object against a model defined by a given model name. The value of the HTTP request parameter
:id will be used as the default lookup value.
LoadModel will give you the ability to require an instance be found and/or override several other default behaviors.
class SillyFellowController < Application load_model :silly_fellow def action @silly_fellow.do_something end end
You can require that a model instance be found for all actions or given actions. Default behavior is to not require that a model instance be found. When require is on and a record is not found, a
ThumbleMonks::RequiredRecordNotFound Exception is thrown; which extends from ActiveRecord::RecordNotFound, for your convenience.
To turn require on for all actions, simply pass true to a provided
:require attribute, like so:
load_model :silly_fellow, :require => true
To turn require on for specific actions, pass an array of action names to
:require. The model will be loaded for all actions, regardless of whether or not required is provided, but the exception will only be raised when an record is not found for the provided actions.
load_model :silly_fellow, :require => [:show, :update]
To use a different parameter key and model than the default, you can provide the values in the
:class options (though not necessary to provide them together), like the following:
load_model :foo, :class => :user, :parameter_key => :bar_id
In the above example,
load_model will assume the parameter_key and the model's primary/foreign key are both the same. For instance, the above example would result in a call like the following:
@foo = User.find_by_bar_id(params[:bar_id])
If you want to use a different lookup/foreign key than the default, you can also provide that key name using the
:foreign_key parameter; like so:
load_model :foo, :class => :user, :parameter_key => :bar_id, :foreign_key => :baz_id
Which would result in a call similar to the following:
@foo = User.find_by_baz_id(params[:bar_id])
If you want to only use
load_model for some actions, you can still name them as you would with a
:except. If you provide an
:only and an
:only will always win out over
:except when there are collisions (i.e. you provide both in the same call)
load_model :foo, :only => [:show] load_model :bar, :except => [:create]
Load Model supports a :through option. With :through, you can load a model via the association of an existing loaded model. This is especially useful for RESTful controllers.
load_model :user, :require => true, :parameter_key => :user_id load_model :post, :through => :user
In this example, a @post record will be loaded through the @user record with essentially the following code:
All of the previously mentioned options still apply (:parameter_key, :foreign_key, :require, :only, and :except) except for the :class option. Meaning you could really mess around!
load_model :user, :require => true, :parameter_key => :user_id load_model :post, :through => :person, :parameter_key => :foo_id, :foreign_key => :baz_id
Would result in a call similar to the following:
Require works as you would expect.
If you would like load_model to not assume a pluralized association name, you can provide the association name with the :association option. Like so:
class Person < ActiveRecord::Base has_many :blog_postings end class PostController < ActionController::Base load_model :post, :through => :person, :assocation => :blog_postings end
Perhaps you don't need to do a subquery on a model's association and you just need to load a model from another's
has_one association. This would be impossible in the above example. Instead, will want to use the :from option. Like so:
class Post < ActiveRecord::Base belongs_to :user end class PostController < ActionController::Base load_model :post load_model :user, :from => :post end
The example is contrived, but you get the point. Essentially, this would do the same as writing the following code:
@post = Post.find_by_id(params[:id]) @user = @post.user
sudo gem install thumblemonks-load_model
- Ruby 1.8.6 or higher
- Rails 2.x or higher
Anyone who developed, discussed, or any other way participated in HTTP, REST, and Rails.
Justin Knowlden firstname.lastname@example.org