what does redirect_to(@model) means in rails?

Question

From this url http://www.helloworlder.com/?p=6 i found the syntax for redirect_to or render, expects a string.

Like this:

render(:action=>’my_action’)
redirect_to(:action=>’my_action’)

But in ruby rails guides i see something like redirect_to(@model). It is stated in their docs that it will go to show action. Please explain what does redirect_to(@model) means.

Thanks

Answer 1

For example, you have a Post model.

redirect_to @model will take you to this page:

http://yourapp/posts/:id/show

Answer 2

You can look at the source here: https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb

When redirect_to takes a Model, it filters through a few methods to get the path calling the polymorphic_url method. The API for this method [1] actually has a lot of details, copied from the comments here:

  # Constructs a call to a named RESTful route for the given record and returns the
  # resulting URL string. For example:
  #
  #   # calls post_url(post)
  #   polymorphic_url(post) # => "http://example.com/posts/1"
  #   polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1"
  #   polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1"
  #   polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1"
  #   polymorphic_url(Comment) # => "http://example.com/comments"
  #
  # ==== Options
  #
  # * <tt>:action</tt> - Specifies the action prefix for the named route:
  #   <tt>:new</tt> or <tt>:edit</tt>. Default is no prefix.
  # * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
  #   Default is <tt>:url</tt>.
  #
  # ==== Examples
  #
  #   # an Article record
  #   polymorphic_url(record)  # same as article_url(record)
  #
  #   # a Comment record
  #   polymorphic_url(record)  # same as comment_url(record)
  #
  #   # it recognizes new records and maps to the collection
  #   record = Comment.new
  #   polymorphic_url(record)  # same as comments_url()
  #
  #   # the class of a record will also map to the collection
  #   polymorphic_url(Comment) # same as comments_url()

Essentially, the answer to your question is that it calls (equivalently) the model_path(@model) method for the model.

[1] http://apidock.com/rails/ActionController/PolymorphicRoutes/polymorphic_url