Rails router, route, path, URL, resource routing

When it come to routing, there is a lot of confusing terms. In this blog, I'll try to shed some light on their meanings.

Router
Rails router is just a piece of code that handles HTTP verb and URL combos and dispatch them to a controller's action.

Route
Route is just the mapping from HTTP verb and URL combo to controller's action.
For example

get '/patients/:id', to: 'patients#show'

Path vs URL
Paths and URLs are easy to be confused.
Say we have a users controller, we can have a path and a URL for it, shown below.
Path => /users
URL => http://www.example.com/users

As we can see here, URLs are just paths prefixed with the current host, port and path prefix.

Resource Routing
In Rails, resource routing allows you to quickly declare all of the common routes for a given resourceful controller by using a single line. For example, you have a controller called photos.

resource :photos

By adding this line into our routes.rb file, we creates the following seven routes.

HTTP Verb	Path	Action	Used for
GET	/photos	index	display a list of all photos
GET	/photos/new	new	return an HTML form for creating a new photo
POST	/photos	create	create a new photo
GET	/photos/:id	show	display a specific photo
GET	/photos/:id/edit	edit	return an HTML form for editing a photo
PATCH/PUT	/photos/:id	update	update a specific photo
DELETE	/photos/:id	destroy	delete a specific photo

For example, if Rails application receives a incoming request for 

GET /photos/1

The router would dispatch that request to the show action in the photos controller with {id: '1'} in params.