Rails Decal

Lecture 4 - CRUD from the browser

CRUD

Refers to all of the major functions that are implemented in relational database applications

Get stoked!!

rails generate model Book title:string description:text

Our database

rake db:migrate

Our database

Form to create a book

Title:

Description:

Submit

Some value

1. Browser sends GET request

2. Your rails server receives this request

3. routes.rb specifies which controller action

4. Your controller action renders the view

What's actually happening

<%= form_for Book.new, url: {action: "create"} do |f| %>
  Title: <%= f.text_field :title %>
  Description: <%= f.text_area :description %>
  <%= f.submit "Create" %>
<% end %>

<form accept-charset="UTF-8" action="/books" class="new_book"
id="new_book" method="post">
  Title: <input id="book_title" name="book[title]" type="text">
  Description: <textarea id="book_description" name="book[description]"></textarea>
  <input name="commit" type="submit" value="Create">
</form>

Corresponding HTML

params

<form accept-charset="UTF-8" action="/books" class="new_book"
id="new_book" method="post">
  Title: <input id="book_title" name="book[title]" type="text">
  Description: <textarea id="book_description" name="book[description]"></textarea>
  <input name="commit" type="submit" value="Create">
</form>

Parameters: {"utf8"=>"✓", "authenticity_token"=>"ZtSPt/l/iQCBKhrA+2iJ3HServkqyogWYb9f4YpJyuk=",
"book"=>{"title"=>"Harry Potter", "description"=>"Sleepy Hallows"}, "commit"=>"Create"}

def create
    @book = Book.new(params[:book])
    @book.save
end

params[:book] = {"title"=>"Harry Potter", "description"=>"Sleepy Hallows"}

params = {"utf8"=>"✓", "authenticity_token"=>"ZtSPt/l/iQCBKhrA+2iJ3HServkqyogWYb9f4YpJyuk=",
"book"=>{"title"=>"Harry Potter", "description"=>"Sleepy Hallows"}, "commit"=>"Create"}

@book = Book.new({"title"=>"Harry Potter", "description"=>"Sleepy Hallows"})

Our params

Create

Strong parameters

We need to filter

parameters!!

Prefixes create a method that corresponds to the url for the action

    Prefix Verb URI Pattern          Controller#Action
    books  POST /books(.:format)     books#create
books_new  GET  /books/new(.:format) books#new
     book  GET  /books/:id(.:format) books#show

Prefixes end with _path or _url

    Means_this     Verb URI Pattern          Controller#Action
    books_path     POST /books(.:format)     books#create
books_new_path     GET  /books/new(.:format) books#new
     book_path     GET  /books/:id(.:format) books#show

<%= form_for @book, url: {action: "update"} do |f| %>
  Title: <%= f.text_field :title %>
  Description: <%= f.text_area :description %>
  <%= f.submit "Update" %>
<% end %>

<form accept-charset="UTF-8" action="/books/22" class="edit_book" id="edit_book_22" method="post">
  Title: <input id="book_title" name="book[title]" type="text" value="Harry Potter">
  Description: <textarea id="book_description" name="book[description]">Sleepy Hallows</textarea>
  <input name="commit" type="submit" value="Update">
</form>

Corresponding html

Resources

resources :books

Same as

  get '/books', to: 'books#index'
  post '/books', to: 'books#create'
  get '/books/new', to: 'books#new', as: 'books_new'
  get 'books/:id/edit', to: 'books#edit', as: 'edit_book'
  get 'books/:id', to: 'books#show', as: 'book'
  patch 'books/:id', to: 'books#update'
  put 'books/:id', to: 'books#update'
  delete 'books/:id', to: 'books#destroy'

SOAK IT IN!!

The adventure begins

http://bit.ly/1xHQLXH

Our guide :)