instance method
to_param
Ruby on Rails edge
Since v3.2.22.5Signature
to_param()Returns a String, which Action Pack uses for constructing a URL to this object. The default implementation returns this record’s id as a String, or nil if this record is unsaved.
For example, suppose that you have a User model, and that you have a ‘resources :users` route. Normally, user_path will construct a path with the user object’s ‘id’ in it:
“‘ user = User.find_by(name: ’Phusion’) user_path(user) # => “/users/1” “‘
You can override to_param in your model to make user_path construct a path using the user’s name instead of the user’s id:
“‘ class User < ActiveRecord::Base
def to_param # overridden
name
end
end
user = User.find_by(name: ‘Phusion’) user_path(user) # => “/users/Phusion” “‘
Source
# File activerecord/lib/active_record/integration.rb, line 61
def to_param
id = self.id
return unless id
# Only composite primary keys need their values joined. A single
# integer or string key is stringified directly, without the wrapping
# array that Array(id).join would allocate. The string is still copied
# so that callers never hold the record's own attribute value.
case id
when Integer then id.to_s
when String then id.dup
else Array(id).join(self.class.param_delimiter)
end
end
Defined in activerecord/lib/active_record/integration.rb line 61
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Defined in ActiveRecord::Integration