Creating Idea route in Rails

In the previous page, we have created our first three ideas while playing around with Rails console].

In this page, we will setup the required route in our application which will help us to display those ideas in the browser.

Request and response flow

Following image should help you understand how a request from browser goes to routes.rb, ideas_controller.rb, fetch first idea from database, process by ideas_controller.rb again, through show.html.erb displayed to the browser.

Routing error

Let’s try typing url https://localhost:3000/ideas/1 in our browser and see what happens.

You will encounter following error and it is expected.

Routing Error

No route matches [GET] "/ideas/1"
...

Fixing routing error

Let’s try to understand error here.

It says, No route matches [GET] "/ideas/1". Typically this is a HTTP GET request. In Rails, we can map such route in the routes.rb file as following.

Rails.application.routes.draw do
  resources :ideas, only: [:show]
end

NOTE: only: [:show] means to define only route for ideas/:id where id is the id of idea.

Restart the Rails server (Ctrl + C and rails s) every time you change the 'routes.rb' to reflect the changes.

After updating the routes.rb file with above lines, the error should be replaced with following different error:

Routing Error

uninitialized constant IdeasController Did you mean? Ideastore
...

That we will fix in the next page.

CRUD and REST

CRUD

CRUD represents following:

C: Create
R: Read
U: Update
D: Delete

CRUD are the standard four ways through which we can interact with data. These are the basic functions that all models should have.

REST

REST stands for REpresentation State Transfer.

REST is an architectural pattern for defining routes. It is a way of mapping the HTTP verbs like GET, POST, PATCH/PUT or DELETE with the CRUD actions.

In general, CRUD actions are mapped to the following HTTP actions:

Action	HTTP Verb
Create (C)	PUT/POST
Read (R)	GET
Update (U)	POST/PUT
Delete (D)	DELETE

Resourceful routing

The line resources :ideas provides following different routes which maps to HTTP Verbs (GET/PUT/POST/DELETE/PATCH) and controller actions.

Rails provides well defined routing mechanism for CRUD which properly map with HTTP verbs.

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

See Resourceful routing from Ruby on Rails Guides to understand more.

Route helpers

Creating a resourceful route will also expose a number of helpers to the controllers or views in your application. In our case resources :ideas has given us following helpers:

Helper	URL
`ideas_path`	`/ideas`
`new_idea_path`	`/ideas/new`
`edit_idea_path(:id)`	`/ideas/:id/edit`
`idea_path(:id)`	`/ideas/:id`

Checking available routes

Rails provide a handy command to check the available routes in your application. Type following to see yourself:

$ rails routes | grep idea
  idea GET    /ideas/:id(.:format)    ideas#show

NOTE: rails routes will list all the routes available in the app.

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