RubyDoc.info: File: README – Documentation for ffmike-from_param (1.0.3)

FromParam

This plugin is an addition to ActiveRecord::Base that establishes a better convention for finding records based on parameters. It adds a “from_param” class method to ActiveRecord::Base as a convention for fetching a model from a URL parameter. By default it will find a record based on the to_i of the passed in parameter, but storing a parameter in a column is where it becomes especially useful.

If you create a ‘param’ column in your table (or any other column using set_param_column), the to_param of your record will automatically be saved to that column whenever you save the record, and you will be able to retrieve it using just a simple Model.from_param call with the generated to_param. It is probably wise to add an index to the param column if you use one.

It’s time to move away from generated-key-dependence, and this plugin is an attempt to make that easy, painless, and work easily within the existing systems.

Example

# default behavior

class User < ActiveRecord::Base
  def to_param
    "#{id}-#{first_name.downcase}-#{last_name.downcase}"
  end
end

class UsersController < ApplicationController
  # GET /users/1-bobby-mcfarin
  def show
    @user = User.from_param(params[:id]) # => <User id=1 first_name="Bobby" last_name="McFarin">
  end
end

# using a 'param' column, in this case 'slug'. Note the use of String.urlize to make the title URL-friendly.
# On Rails 2.2+, String.urlize is an alias for Rails built-in Inflector.parameterize.

class Post < ActiveRecord::Base
  set_param_column "slug" # defaults to "param"
  def to_param
    "#{created_at.strftime("%Y-%m-%d")}-#{title.urlize}"
  end
end

class PostsController < ApplicationController
  # GET /posts/2008-04-26-from-param-plugin-released
  @post = Post.from_param(params[:id]) # => <Post title="From Param: Plugin Released" created_at="2008-04-26">
end

Note: You will need to have the rspec gem installed to run the tests.

Resources

GitHub: github.com/mbleigh/from_param Lighthouse: mbleigh.lighthouseapp.com/projects/10478-from-param