Pet App!

Starter code and challenges for Validations & Error-Handling in Rails.

Getting Started

1. Fork this repo, and clone it into your WDI class folder on your local machine.
2. Run bundle in the Terminal to install gems from the Gemfile. (Feel free to take a look at what's included, first.)
3. Run rails db:create db:migrate in the Terminal to create your local database and run the migrations.
4. Run rails s in the Terminal to start your server.
5. Navigate to localhost:3000 in the browser - you should see a generic site#index page.
6. Run rails routes to see what routes are available in the app.

Part 1: Owner Validations and Error Handling

Add Model Validations

1. Run rspec spec/models/owner_spec.rb from the Terminal to see the tests that are set up for the Owner model.

2. Add validations to the Owner model. Owners have the following restrictions:

• owners are required to have a first_name, a last_name, and an email
• an owner's first_name, last_name, and email must each be at most 255 characters long
• emails must be unique; that is, no two owners can have the same email
• emails must contain an @ symbol (hint: this checks the format)

See the Active Record Validation guide for guidance.

2. In the Terminal, open up the Rails console, and try adding an invalid owner to the database using the .create method:

irb(main):001:0> guy = Owner.create({
irb(main):001:1>   first_name: "Guybrush",
irb(main):001:2>   last_name: "Threepwood"
irb(main):001:3> })

What happens?

3. Now try storing the invalid owner in memory with the .new method, and check if it's valid:

   irb(main):001:0> guy = Owner.new({
   irb(main):001:1>   first_name: "Guybrush",
   irb(main):001:2>   last_name: "Threepwood"
   irb(main):001:3> })
   irb(main):001:4> guy.valid?

4. Still in the Rails console, use .errors.full_messages to display the user-friendly error messages for the invalid owner you just created.

Refactor Controller to Handle Errors

1. The owners#create method currently looks like this:

#
# app/controllers/owners_controller.rb
#
def create
  owner = Owner.create(owner_params)
  redirect_to owner_path(owner)
end

The owner_params method is set up to use Rails strong parameters.

What happens when you navigate to localhost:3000/owners/new in the browser and try to submit a blank form?

Refactor your owners#create controller method to better handle this error. Hint: Use .new and .save.

Hint: which methods to use?

Try `.new` and `.save` so it's easier to see if there's an error.

Hint: what to do if there's an error?

For now, redirect back to the page with the form. If you don't remember the path helper method to use, `rails routes` in your Terminal and check the prefixes!

2. Once you've refactored owners#create to redirect in the case of an error, add flash messages to show the user the specific validation error they triggered, so they won't make the same mistake twice.

Hint: where to set the flash message?

Set the flash message in the controller by adding the message into the `flash` hash. The `flash` hash is special short-term memory in Rails that lasts just until the end of the *next* request - which makes it perfect to use with redirects! (See the [Rails Flash message guide](http://api.rubyonrails.org/classes/ActionDispatch/Flash.html) for syntax.)

Hint: where to display the flash message?

Create a place to render the flash message in the main application layout (`app/views/layouts/application.html.erb`). You should template in the contents of your flash hash.

Editing Owners

1. You already have routes for owners#edit and owners#update, since routes.rb calls resources :owners. Now, set up controller methods for owners#edit and owners#update, as well as a view for editing owners (edit form).

2. Make sure your owners#update method also handles errors by redirecting if the user submits invalid data and displaying a flash message in the view.

3. Common keys for flash messages are :notice, which just displays some information, and :error, which means something has gone wrong. Add styling to visually distinguish between these kinds of flash messages.

4. If you look at seeds.rb, you'll see FFaker is set up to generate seed data. In your Rails console, try FFaker::PhoneNumber.phone_number a few times. Just like real user data, the phone numbers don't have a standard format. Fill in the normalize_phone_number method so that it will:

• remove 1 from the beginning of the owner's phone number, and
• remove the characters (, ), -, and . from the owner's phone number.

The before_save method makes it so the normalize_phone_number method gets called whenever an owner is about to be saved in the database.

Part 2: Owners Have Many Pets

1. In addition to owners, this app has a model for pets. In this app, each owner will have many pets, and each pet will belong to one owner. Change the Owner and Pet models to reflect this relationship.

2. Add a foreign key to the Pet table so that each pet stores a reference to its owner.

See the ActiveRecord Migrations Rails guide for how add a foreign key to a table that's already been created.

Hint: how to generate migration to add foreign key?

The example from the docs adds a user foreign key to a products table, by running `bin/rails generate migration AddUserRefToProducts user:references`, but you can also use something like `rails g migration AddUserRefToProducts user:belongs_to`. Just replace the example models with the names this app needs!

1. In the Terminal, open up the Rails console, and create a few associated instances of pets and owners.

irb(main):001:0> ash = Owner.create({
irb(main):001:1>   first_name: "Ash",
irb(main):001:2>   last_name: "Ketchum",
irb(main):001:3>   email: "a_ketchum@example.com",
irb(main):001:4>   phone: "(03) 1234-5678"
irb(main):001:5> })

irb(main):001:0> pikachu = Pet.create({
irb(main):001:1>   name: "Pikachu",
irb(main):001:2>   breed: "pokemon"
irb(main):001:3> })

irb(main):001:0> ash.pets << pikachu

Compare ash's id with pikachu's new owner_id.

Model Validation for Pets

1. Practice TDD. Pets are required to have both name and breed, and name cannot be longer than 255 characters. Using the Owner model tests as an example, write tests for these validations.

Note that two gems are included to add extra Rails-appropriate RSpec features to this project: rspec-rails and shoulda-matchers. You can see where they're set up in Gemfile and spec/rails_helper.rb.

Hint: Where to code `Pet` model tests?

The tests for the `Pet` model belong in `spec/models/pet_spec`. This file already exists and was generated when the command `rails g model pet ...` was run.

Hint: Where to look for `Owner` test examples?

The tests for the `Owner` model are in `spec/models/owner_spec`.

1. Add validations to the Pet model. Then, test your validations with rspec spec/models/pet_spec.rb. If you're not sure of the quality of your tests, try a few valid and invalid inputs in the console to make sure invalid inputs don't get saved.

2. At this point, you can "comment in" the parts of the db/seeds.rb file that relate to pets and run rails db:seed. This will destroy all old pets and create new ones.

Pet Routes

Nest routes for pets inside the routes for owners. Start with just an few routes:

# config/routes.rb
resources :owners do
  resources :pets, only: :index, :show, :new, :create
end

Run rails routes in the Terminal to see the new routes. You can see a table of nested routes and each route's purpose in the Routing Rails guide.

Pet Index and Show

1. On the owner show view, add a "view this owner's pets" link. Remember to use link_to. The link should go to the path that will show all of that owner's pets. Reference the route table in the Routing Rails guide.

2. The pets index view will show all the pets for a particular owner. Finish filling in the pets index view template. The pets index view should list the names of all pets belonging to the owner.

Hint: What data will this view need from the controller?

Since we're looking for the pets from a single owner, the view will need to know which owner to use (`@owner`). If you have your model relationship set up correctly, an owner's pets are simply `@owner.pets`.

1. Add a link to each pet's name that leads to the pet's show page. Remember to use link_to.

2. Fill in the pets#index controller action so that the view has the necessary information to display.

3. Fill in the pet show template to display the pet's name and breed.

4. Fill in the pets#show controller action to give this view the necessary information.

Pet New and Create

1. On the pet index view, add a link to the path for the new pet form. Remember to reference the route table in the Routing Rails guide.

2. Create a new pet view that renders a form. The form should have text fields for the pet's name and breed. Research the syntax for form_for with nested resources.

Hint: research help?

The top google result for "form_for nested resource" is a StackOverflow question, and the top answer has the necessary syntax. Take a look at [the answer](http://stackoverflow.com/a/4611932).

1. Add a new action to the pets controller, and have the controller retrieve the data necessary to create a new pet for a particular owner.

Hint: what data is necessary?

Like with most `new` actions, you'll want a dummy new pet to use with the `form_for` helper. Since this pet is being added to a particular owner, you'll also need to use that owner's information.

1. Add a create action to the pets controller. This action will need to find the proper owner, make and save a new pet, and add the pet to the owner's list of pets. It can redirect to the new pet's show page when the creation is successful.

2. If there is an error in the creation of the new pet, add a flash message. Redirect back to the new pet form for that owner.

Part 3: Choose Your Own Adventure

Three types of stretch challenges lay before you. Pick and implement the set(s) you find interesting. Solutions are provided.

Circumnavigate the Site for User Experience

Practice using path helper methods by adding link_tos to help users move among the pages of your site. Consider adding:

• a link to the owner index from the owner show page
• a link to the owner's show page from the list of their pets
• a link to the owner's list of pets from the pet show page
• a link to the site index on every page (keep it DRY!)

Follow the Routes to Full CRUD

Create or fill in routes, controllers, and views for the missing crud actions for owners and pets. Choose one route at a time. It might be easiest to start with destroy; just remember the difference between destroy and delete!

Play with Pets!

Practice your Ruby skills - get more time with the Date and DateTime built-in classes.

1. Generate and run a migration to add a date_of_birth field to the Pet model. The type of this field should be date. Display the pet's date_of_birth in the view for pets#show.

2. Fill in the Pet model's date_of_birth_cannot_be_in_the_future method. This method should add an error to the validation errors if the pet's date_of_birth is in the future. See the Validations Rails guide.

3. Fill in the Pet model's age instance method. If the pet instance has a date_of_birth, this method should calculate and return the pet's age in years (as a decimal). If the pet doesn't have a date_of_birth, the age method should return nil. Display the pet's age in the view for pets#show.