instance method
to_param
Ruby on Rails edge
Since v4.1.16Signature
to_param(method_name = nil)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 # => “123-fancy-pants” User.find(params).id # => 123 “`
Parameters
-
method_nameopt = nil
Source
# File activerecord/lib/active_record/integration.rb, line 171
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
Defined in activerecord/lib/active_record/integration.rb line 171
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Defined in ActiveRecord::Integration::ClassMethods