以请求未到达的“路径”结尾的控制器操作

Question

对于我的生活，我不明白为什么我的控制器不进行SQL调用，然后将它传递到视图中。

在我的应用程序的每一个其他部分，包括在这个控制器中的其他方法，不用担心。但不管是什么原因我都搞不好。

app/controllers/referrals_controller.rb

class ReferralsController < ApplicationController

    def index # <- This works fine. 
        @referrals = Referral.all
        @referral = Referral.first 
        @reminder = Reminder.first 
        respond_to(:js, :html)
    end 

    def category_path # <- This doesn't work
        @referrals = Referral.where(:category => :option)
        @referral = @referrals.first 
        respond_to :js 
    end 

    def fetch_content # <- This works fine. 
        @referral = Referral.find(params[:follow_id])
        respond_to :js 
    end 
    ...
end 

Config/routes.rb

Rails.application.routes.draw do
  ...
  resources :referrals

  get '/referrals' => 'referrals#index'
  get '/category_path' => 'referrals#category_path', as: 'category'
  get '/fetch_content' => 'referrals#fetch_content', as: 'fetch_content'
end 

以下是我对这些路线的看法。

app/views/referrals/index.html.erb

<%= link_to 'Immigration Referral', category_path(:option => 'Immigration Referral'), remote: true, class: 'category-links' %> - 
...
<%= link_to referral.title, fetch_content_path(:follow_id => referral.id), remote: true %>

尽管category_path和fetch_content的设置实际上是相同的，但是fetch_content工作得很完美，category_path甚至不做SQL查询。在我使用fetch_content的地方日志显示

Started GET "/fetch_content?follow_id=1" for 127.0.0.1 at 2018-02-24 09:22:16 -0600
Processing by ReferralsController#fetch_content as JS
  Parameters: {"follow_id"=>"1"}
  User Load (0.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Referral Load (0.3ms)  SELECT  "referrals".* FROM "referrals" WHERE "referrals"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Rendering referrals/fetch_content.js.erb
  Rendered referrals/_content.html.erb (0.3ms)
  Rendered referrals/fetch_content.js.erb (2.6ms)
Completed 200 OK in 19ms (Views: 14.9ms | ActiveRecord: 0.5ms)

但是，当我使用category_path时，结果是：

Started GET "/category_path?option=Immigration+Referral" for 127.0.0.1 at 2018-02-24 09:22:22 -0600
Processing by ReferralsController#category_path as JS
  Parameters: {"option"=>"Immigration Referral"}
  User Load (0.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Rendering referrals/category_path.js.erb
  Rendered referrals/_titles.html.erb (0.7ms)
  Rendered referrals/_content.html.erb (0.4ms)
  Rendered referrals/category_path.js.erb (32.6ms)
Completed 200 OK in 80ms (Views: 62.1ms | ActiveRecord: 0.2ms)

在我看来，@referrals.nil?正在返回true，如果它没有进行一个SQL调用，我就会期望它返回true。我的问题是，为什么？！为什么我的控制器不进行SQL调用。我甚至尝试更改为更简单的东西，如@referrals = Referral.all，但这仍然不会触发SQL调用。发生什么事了呢？

Answer 1

后缀"path“似乎不适用于控制器中的任何操作，可能是因为它应该与Rails管理的路由发生冲突，如@apneadiving所指出的那样。

如果您设置一个带有后缀路径的操作，并尝试列出该控制器的操作方法，您将看到该操作不存在：

class ReferralsController < ApplicationController
  ...

  def category_path # <- This doesn't work
    ...
  end 

  def fetch_content_path # <- This works fine. 
    ...
  end 
end

控制器有两个动作，用*_path完成。现在，请使用您获得的操作方法：

ReferralsController.action_methods
=> #<Set: {"new", "index", "update", "create", "edit", "destroy", "show"}>

如果删除操作名称中的最后一个"h“字符，会发生什么情况？

ReferralsController.action_methods
=> #<Set: {"new", "index", "update", "create", "edit", "destroy", "show", "category_pat"}>

操作出现在那里，这就是为什么可以到达您的fetch_content操作，而类别之一却不能。解决方案只是重命名操作方法。