Simple Rails Q: Where is this variable defined?

Question

I'm following this tutorial (seems good) for Rails. After I run

ruby script/generate scaffold Post

then this link works in one of the erb files:

<%= link_to "My Blog", posts_path %>

WHY? I've looked for "posts_path" in the whole app and it's nowhere to be found. On the other hand, this

<%= link_to "My Blog", home_path %>

does not work, and it's also a Controller.

Where is the posts_path defined?

Answer 1

posts_path is a named route you get for free from the route that was added by script/generate scaffold. See routes.rb you should see something like this:

map.resources :posts

See the API docs for information on what other named routes you get for free.

Also you can run rake routes and see what all your routes.rb is giving you.

If you want a home_path named route add a line like this to your routes.rb:

map.home '/home', :controller => "home", :action => "index"

Answer 2

I believe that "posts_path" is created dynamically by Rails at runtime. Look at your routes.rb file - Home is probably not defined the same way as Posts. It has nothing to do with you controllers, it's dependent on the route definition.

Answer 3

map.root :controller => "home" would be a shorter way of writing the path to your home directory. This will use / has the home, and not /home. If you still want to use /home (and home_path), map.home 'home', :controller => "home" will do the same thing.

There's a great guide written by Mike Gunderloy about everything there is to know about routing.