Learn Rails5.2 Routes摘录

Posted 2020-11-19 chentianwei

Naming a Route

 

get ‘home/index‘, as: "different_name"

会得到prefix: different_name代替home_index, 这个是路径的名字。

 

get ‘home/ping‘, to: "home#pong" 

to方法，定义到哪个控制器的哪个action。 这会改变默认的控制器的action。而控制器会指向view。

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Paramter 

 

通过浏览器输入的URI Pattern ，可以导向控制器的某个action

 

在router.rb中

  resources :posts

  get ‘:year(/:month(/:day))‘, to: ‘posts#index‘

 

Verb  URI Pattern               Controller#Action

GET    /:year(/:month(/:day))(.:format)		 posts#index 

 

解释：这里参数:year是必须的,括号里的是可选的。

http://localhost:3000/2018/01/01 

Started GET "/2018/01/01" for 127.0.0.1 at 2018-06-18 09:52:25 +0800

Processing by PostsController#index as html

  Parameters: {"year"=>"2018", "month"=>"01", "day"=>"01"}

  Rendering posts/index.html.erb within layouts/application

  Post Load (0.1ms)  SELECT "posts".* FROM "posts"

  ? app/views/posts/index.html.erb:16

  Rendered posts/index.html.erb within layouts/application (1.8ms)

Completed 200 OK in 39ms (Views: 37.7ms | ActiveRecord: 0.1ms)

 

解释：在controller的index动作中， 你可以利用params[]来存取定义在URL中的值。 

valid_date?方法，找不到出处？

  def index

    if Date.valid_date?(params[:year].to_i, params[:month].to_i, params[:day].to_i)

      start_date = Date.parse("#{params[:day]}.#{params[:month]}.#{params[:year]}")

      end_date = start_date

    elsif Date.valid_date?(params[:year].to_i, params[:month].to_i, 1)

      start_date = Date.parse("1.#{params[:month]}.#{params[:year]}")

      end_date = start_date.end_of_month

    elsif params[:year] && Date.valid_date?(params[:year].to_i, 1, 1)

      start_date = Date.parse("1.1.#{params[:year]}")

      end_date = start_date.end_of_year

    end

    if start_date && end_date

      @posts = Post.where(published_on: start_date..end_date)

    end

  end

 

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constraints(constraints={}) 

用于限制url

  get ‘:year(/:month(/:day))‘, to: ‘posts#index‘, constraints: {year: /d{4}/, month: /d{2}/, day: /d{2}/ }

也可以接受块：

 constraints(id: /d+.d+/) do

   resources :posts

 end 

加入??后，id只能输入1.1或者10.11的格式，否则会报告Routing Error. 

 

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Redirect(*args, &block)方法 

用于返回到其他path。设置比较复杂。

  get ‘:year/:month/:day‘, to: redirect("/%{year}/0%{month}/0%{day}"), constraints: { year: /d{4}/, month: /d{1}/, day: /d{1}/ }

 还必须加上??，否则不能导航到控制器的index动作。

  get ‘:year(/:month(/:day))‘, to: ‘posts#index‘, constraints: {year: /d{4}/, month: /d{2}/, day: /d{2}/ }

 

我的理解：第一行代码是返回到第二行代码的路径，然后再指向控制器的index动作。 

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