Ruby on Rails 开发笔记

安装 Ruby on Rails

安装 ruby

RubyInstall for Windows
安装 sqlite

SQLite Download Page

下载 sqlite-tools-win32-x86-......zip
安装 rails

gem install rails

创建应用

MacOS 平台

# 创建新的应用程序

$ rails new blog

$ cd blog

# 安装 yarn

$ brew install yarn

# 安装 webpacker

$ rails webpacker:install

# 启动服务器

$ rails server

# http://localhost:3000 可访问网页

Windows 平台

创建新的应用程序
安装 yarn
安装 node
安装 webpacker

官方示例

Rails 入门

控制器生成器

使用 generate controller 命令（控制器生成器）来自动生成控制器（controller），视图（view）以及动作（action）

# 生成 Welcome 控制器以及它的 index 动作

$ rails generate controller Welcome index

主要生成下面两个文件

app/controllers/welcome_controller.rb

控制器文件
app/views/welcome/index.html.erb

嵌入式Ruby文件
http://localhost:3000/welcome/index

Rails 将把该请求映射为 Welcome 控制器的 index 动作

路由

通过修改 config/routes.rb 文件来设定路由

Rails.application.routes.draw do

  get 'welcome/index'

  resources :articles do

    resources :comments

  end

  root 'welcome#index'

end

使用 routes 命令来确认路由

$ rails routes

              Prefix Verb   URI Pattern                                        Controller#Action

       welcome_index GET    /welcome/index(.:format)                           welcome#index

    article_comments GET    /articles/:article_id/comments(.:format)           comments#index

                     POST   /articles/:article_id/comments(.:format)           comments#create

 new_article_comment GET    /articles/:article_id/comments/new(.:format)       comments#new

edit_article_comment GET    /articles/:article_id/comments/:id/edit(.:format)  comments#edit

     article_comment GET    /articles/:article_id/comments/:id(.:format)       comments#show

                     PATCH  /articles/:article_id/comments/:id(.:format)       comments#update

                     PUT    /articles/:article_id/comments/:id(.:format)       comments#update

                     DELETE /articles/:article_id/comments/:id(.:format)       comments#destroy

            articles GET    /articles(.:format)                                articles#index

                     POST   /articles(.:format)                                articles#create

         new_article GET    /articles/new(.:format)                            articles#new

        edit_article GET    /articles/:id/edit(.:format)                       articles#edit

             article GET    /articles/:id(.:format)                            articles#show

                     PATCH  /articles/:id(.:format)                            articles#update

                     PUT    /articles/:id(.:format)                            articles#update

                     DELETE /articles/:id(.:format)                            articles#destroy

                root GET    /                                                  welcome#index

Articles Comments 控制器

# 生成 Articles 控制器

$ rails generate controller Articles

# 生成 Comments 控制器

$ rails generate controller Comments

Article Comment 模型

# 生成 Article 模型，然后创建 db

$ rails generate model Article title:string text:text

$ rails db:migrate

# 生成 Comment 模型，然后更新 db

$ rails generate model Comment commenter:string body:text article:references

$ rails db:migrate

模型生成器主要生成下面两种文件

app/models/article.rb

app/models/comment.rb

模型文件
db/migrate/20200504035451_create_articles.rb

db/migrate/20200504050736_create_comments.rb

数据迁移指令Ruby文件

模型类代码

app/models/article.rb 文件

class Article < ApplicationRecord

  has_many :comments, dependent: :destroy

  validates :title, presence: true,

                    length: { minimum: 5 }

end

app/models/comment.rb 文件

class Comment < ApplicationRecord

  belongs_to :article

end

控制器类代码

app/controllers/articles_controller.rb 文件

class ArticlesController < ApplicationController

  http_basic_authenticate_with name: "dhh", password: "secret", except: [:index, :show]

  def index

    @articles = Article.all

  end

  def show

    @article = Article.find(params[:id])

  end

  def new

    @article = Article.new

  end

  def edit

    @article = Article.find(params[:id])

  end

  def create

    @article = Article.new(article_params)

    if @article.save

      redirect_to @article

    else

      render 'new'

    end

  end

  def update

    @article = Article.find(params[:id])

    if @article.update(article_params)

      redirect_to @article

    else

      render 'edit'

    end

  end

  def destroy

    @article = Article.find(params[:id])

    @article.destroy

    redirect_to articles_path

  end

private

  def article_params

    params.require(:article).permit(:title, :text)

  end

end

下面是该控制器类所包含的方法以及它们所对应的路由

index（列表）GET /articles
show（显示）GET /articles/:id
new（新建）GET /articles/new
edit（编辑）GET /articles/:id/edit
create（创建）PATCH/POST /articles
update（更新）PUT /articles/:id
destroy（删除）DELETE /articles/:id

app/controllers/comments_controller.rb 文件

class CommentsController < ApplicationController

  http_basic_authenticate_with name: "dhh", password: "secret", only: :destroy

  def create

    @article = Article.find(params[:article_id])

    @comment = @article.comments.create(comment_params)

    redirect_to article_path(@article)

  end

  def destroy

    @article = Article.find(params[:article_id])

    @comment = @article.comments.find(params[:id])

    @comment.destroy

    redirect_to article_path(@article)

  end

  private

    def comment_params

      params.require(:comment).permit(:commenter, :body)

    end

end

下面是该控制器类所包含的方法以及它们所对应的路由

create（创建）PATCH/POST /articles/:article_id/comments
destroy（删除）DELETE /articles/:article_id/comments/:id

welcome 视图代码

app/views/welcome/index.html.erb 文件

<h1>Hello, Rails!</h1>

<%= link_to 'My Blog', controller: 'articles' %>

articles 视图代码

app/views/articles/_form.html.erb 文件

<%= form_with model: @article, local: true do |form| %>

  <% if @article.errors.any? %>

    <div id="error_explanation">

      <h2>

        <%= pluralize(@article.errors.count, "error") %> prohibited

        this article from being saved:

      </h2>

      <ul>

        <% @article.errors.full_messages.each do |msg| %>

          <li><%= msg %></li>

        <% end %>

      </ul>

    </div>

  <% end %>

  <p>

    <%= form.label :title %><br>

    <%= form.text_field :title %>

  </p>

  <p>

    <%= form.label :text %><br>

    <%= form.text_area :text %>

  </p>

  <p>

    <%= form.submit %>

  </p>

<% end %>

app/views/articles/edit.html.erb 文件

<h1>Edit article</h1>

<%= render 'form' %>

<%= link_to 'Back', articles_path %>

app/views/articles/index.html.erb 文件

<h1>Listing articles</h1>

<%= link_to 'New article', new_article_path %>

<table>

  <tr>

    <th>Title</th>

    <th>Text</th>

    <th></th>

  </tr>

  <% @articles.each do |article| %>

    <tr>

      <td><%= article.title %></td>

      <td><%= article.text %></td>

      <td><%= link_to 'Show', article_path(article) %></td>

      <td><%= link_to 'Edit', edit_article_path(article) %></td>

      <td><%= link_to 'Destroy', article_path(article),

                      method: :delete,

                      data: { confirm: 'Are you sure?' } %></td>

    </tr>

  <% end %>

</table>

app/views/articles/new.html.erb 文件

<h1>New article</h1>

<%= render 'form' %>

<%= link_to 'Back', articles_path %>

app/views/articles/show.html.erb 文件

<p>

  <strong>Title:</strong>

  <%= @article.title %>

</p>

<p>

  <strong>Text:</strong>

  <%= @article.text %>

</p>

<h2>Comments</h2>

<%= render @article.comments %>

<h2>Add a comment:</h2>

<%= render 'comments/form' %>

<%= link_to 'Edit', edit_article_path(@article) %> |

<%= link_to 'Back', articles_path %>

comments 视图代码

app/views/articles/_comment.html.erb 文件

<p>

  <strong>Commenter:</strong>

  <%= comment.commenter %>

</p>

<p>

  <strong>Comment:</strong>

  <%= comment.body %>

</p>

<p>

  <%= link_to 'Destroy Comment', [comment.article, comment],

               method: :delete,

               data: { confirm: 'Are you sure?' } %>

</p>