Rails RESTful & CRUD

Rails RESTful

Generate function

Rails g model

rails g model tablename column1 column2
Tablename, this needs to be what your model is going to be called.

Rails 6 has plurallize built in so it'll make the model singular but keep the table plural as is best practice. To set them as other data types just state them as other than a string.

All the useful data types, there are more but these will get the job done most of the time.

string
integer
float
timestamp

Rails g controller

rails g controller ControllerslName controller actions
ControllersName needs to reference the model with the following convention

ModelsController
The controller actions are, by default, empty unless you specifiy them. The convention is the following order

index show new edit create update destroy

This will setup those seven routes in routes.rb as well create app/views/model and .html.erb files for each route

routes.rb
after runing rails g controller command like above the routes.rb file will be created with the following boilerplate code

Rails.application.routes.draw do
  get '/models/index'
  get '/models/show'
  get '/models/new'
  get '/models/edit'
  get '/models/create'
  get '/models/update'
  get '/models/destroy'
end

This is fine as is or it can be refactored down to a single line
resources :models.

If you only generate a controller action as needed then the routes and view file will need to be created manually as you go. This may be a better method of going about building out the basic functionality of your web app to be honest as there will be no routes that are unknown to you as the dev.

side note: I didn't follow that pattern of build only what you need as you go, and in the last code challenge I found myself lost quickly.
While troubleshooting I knew there was more in the app than I had full understanding of.
In the future I will build controller actions out 1 at a time as I need the functionality and route.

To take advantage of resources :models with only specific routes (the buils it as you go method) there is a way to have rails only create those routes you need.

resources :models, only: [:index, :show]

you can add to the list within the brackets as you build out your web app.

controller action methods

For every route you need a controller action method. These live in the ./app/controllers/models_controller.rb file. Each model has a controller and they each inherit from application_controller.rb.

This is a great file to place repeated logic in different models, just have the method in the application_controller.rb and all models will have access to the method

index

def index
  @models = Model.all
end

For index the only thing really needed is @models = Model.all as this will provide the logic needed to be able to access all data in the dB table for the model. This is useful as an index web page that lists out everything - table of contents, or all users, or all whatevers.

show

def show
  @model = Model.find(params[:id])
end

This ensures that a show page for any indivdual record in the dB table for the model can be accessed. This line of code is actually used often in other controller action methods and can be moved to a before_action macro (more on that later though).

new

def new
  @model = Model.new
end

Another brief bit of logic that makes sure the page will send a .new command to the dB to kick off the creation of a new record. Additional logic could go here that would pull in more logic for a New page in the browser.

update

def update
end

This is the best place to any logic for creating, editing, or updating a record. Placing validation logic here will ensure that when you create the update view and use form_for that a submit button will change it's wording to match the actual action. This is super cool rails magic as it will first check if the record id exists, if it does then it'll pull in the record data to your form_for form and the submit button will say 'update'. If there is no record then the form_for form will be empty and the submit button will say 'create'. Also if all routes to any of these actions (craete, or update) are set to the same route than rails again will make sure everything works as expected. Basically just user the update route and rails will take care of it.