Methods
- T
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
# File activerecord/lib/active_record/integration.rb, line 147 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