Rails 入门（1）

必要的环境

• 用 rbenv 安装 ruby
• 用 rvm 安装 node.js
• 安装 yarn
• Mac 自带 SQLite3

安装 ruby

rbenv install 3.0.3

安装 rails

gem install rails -v 7.0.0.rc1

初始化项目

初始化项目，启动项目

rails new rails-blog-1
cd rails-blog-1
bin/rails s

文章列表

在 config/routes.rb 添加路由

Rails.application.routes.draw do
  get "/articles", to: "articles#index"
end

创建 Controller

bin/rails generate controller Articles index --skip-routes

编辑 app/views/articles/index.html.erb

<h1>Hello, Rails!</h1>

重启项目

打开文章列表：http://127.0.0.1:3000/articles，可看到 Hello, Rails!

编辑 config/routes.rb，设置首页

Rails.application.routes.draw do
  root "articles#index"
  get "/articles", to: "articles#index"
end

保存，重新打开 http://127.0.0.1:3000，页面显示和文章列表一样

创建 Model

bin/rails generate model Article title:string body:text

迁移数据

bin/rails db:migrate

往数据库插入一条数据

bin/rails console
article = Article.new(title: "Hello Rails", body: "I am on Rails!")
article.save

修改 app/controllers/articles_controller.rb

class ArticlesController < ApplicationController
  def index
    @articles = Article.all
  end
end

修改 app/views/articles/index.html.erb

<h1>Articles</h1>

<ul>
  <% @articles.each do |article| %>
    <li>
      <%= article.title %>
    </li>
  <% end %>
</ul>

打开 http://127.0.0.1:3000 就能看见页面显示一条文章标题：Hello Rails

文章详情页

编辑路由 config/routes.rb

Rails.application.routes.draw do
  root "articles#index"
  get "/articles", to: "articles#index"
  get "/articles/:id", to: "articles#show"
end

编辑 app/controllers/articles_controller.rb

class ArticlesController < ApplicationController
  def index
    @articles = Article.all
  end
  
  def show
    @article = Article.find(params[:id])
  end
end

新建 app/views/articles/show.html.erb

<h1><%= @article.title %></h1>

<p><%= @article.body %></p>

编辑 app/views/articles/index.html.erb

<h1>Articles</h1>

<ul>
  <% @articles.each do |article| %>
    <li>
      <a href="/articles/<%= article.id %>">
        <%= article.title %>
      </a>
    </li>
  <% end %>
</ul>

现在打开 http://127.0.0.1:3000，点击文章标题，跳转到文章详情页，详情页展示文章标题和内容。

路由

编辑 config/routes.rb，用 resources 代替

Rails.application.routes.draw do
  root "articles#index"
  resources :articles
end

可以用下面命令查看路由：

bin/rails routes

编辑 app/views/articles/index.html.erb，替换 a 标签

<h1>Articles</h1>

<ul>
  <% @articles.each do |article| %>
    <li>
      <%= link_to article.title, article %>
    </li>
  <% end %>
</ul>

打开 http://127.0.0.1:3000，内容没变。