ActiveRecord::Integration::ClassMethods (original) (raw)

Methods

T

• to_param

Instance Public methods

to_param(method_name = nil)Link

Defines your model’s to_param method to generate “pretty” URLs using method_name, which can be any attribute or method that responds to to_s.

class User < ActiveRecord::Base
  to_param :name
end

user = User.find_by(name: 'Fancy Pants')
user.id         # => 123
user_path(user) # => "/users/123-fancy-pants"

Values longer than 20 characters will be truncated. The value is truncated word by word.

user = User.find_by(name: 'David Heinemeier Hansson')
user.id         # => 125
user_path(user) # => "/users/125-david-heinemeier"

Because the generated param begins with the record’s id, it is suitable for passing to find. In a controller, for example:

params[:id]               # => "123-fancy-pants"
User.find(params[:id]).id # => 123

Source: show | on GitHub

def to_param(method_name = nil) if method_name.nil? super() else define_method :to_param do if (default = super()) && (result = send(method_name).to_s).present? && (param = result.squish.parameterize.truncate(20, separator: /-/, omission: "")).present? "#{default}-#{param}" else default end end end end