What we're going to do:
- Play follow-the-error to guide our development
- Add routes, a controller, and a view to make a home page
- Learn how to read the routing info at http://localhost:3000/rails/info
Getting Started
That Rails default page is boring. Let's add a page to list the open jobs at RailsBridgeCorp!
To start, let's visit the page that we want to put our jobs on: http://localhost:3000/jobs.
Error! Woo!!!
No route matches [GET] '/jobs'
That's pretty reasonable, since we currently don't have any routes at all right now.
Adding Routes
So it's looking for a route, but can't find one. Let's add one!
Open up the routes file. It's in the config directory, called routes.rb. If you're using Atom, you can open it using keyboard shortcuts:
- Hitting cmd + p (on Mac) or ctl + p (on PC)
- typing in
route
- hitting enter
Magic! (Atom is using fuzzy search, so you can use the entire file path, or just part of the filename to go to files.)
We're going to need a resource route, which will create EIGHT different routes for us. Add this to line two:
resources :jobs
Discussion: How to read the routes page.
In your browser, visit http://localhost:3000/rails/info. Go over each of the columns and how to read it.
- Helper
- HTTP Verb (don't worry about going to in-depth with these yet)
- Path
- Controller#Action
Why does the Helper column sometimes not have anything?
Can you find the line that will make /jobs a route?
Error! Woo!!!
uninitialized constant JobsController
Why does Rails now think it needs a JobsController?
Add a controller
Time for a shortcut!!! Unlike the scaffold that we make in Suggestotron that makes about a million different files, we're just going to use a Rails generator to make the files we need.
Type this in the terminal:rails generate controller jobs
Discussion: What did that command do?
What files were made by that last command? Are they awesome?
How will this change what error we see when we go to the jobs page?
Error! Woo!!!
The action 'index' could not be found for JobsController
What is telling Rails to look in JobsController?
Let's go back to http://localhost:3000/rails/info again and look at what controller and method (AKA action) the route /jobs is pointing to.
It's looking for a method called index on the jobs controller! Since there isn't a controller method for this route, we'll need to add it.
Open up your jobs controller (again, try to use keyboard shortcuts: cmd+p on Mac or ctl+p on PC to find the file at app/controllers/jobs_controller.rb).
Add the index method to the controller:
class JobsController < ApplicationController
def index
end
end
Error! Woo!!!
JobsController#index is missing a template for this request format and variant.
What's a template? How does Rails decide to look for the template associated with JobsController's index action?
Talk through what Rails is trying, and failing, to do, and how file names and method names are important here.
Add a view
Within app/views/jobs, add a file called index.html.erb.
Save that file, and refresh http://localhost:3000/jobs
NO ERROR!?!?! How boring. Let's add some content so we can be more confident that this really a thing.
Within index.html.erb, add this (or the name of your fictional megacorp):
<h1>RailsBridgeCorp Open Jobs</h1>
DONE! Well, except that we don't have any jobs. And even though we could hand-code a table of job titles here, that would be awfully tedious and we'd probably get sick of adding job postings every time someone came up with a new volunteer position. Let's empower people to add their own postings!