为什么我在论坛中的评论没有保存到数据库中？

Question

我正在使用我在 youtube 上找到的教程使用 ruby​​ on rails 创建一个论坛网站。到目前为止，我已经完成了 80%，没有任何问题。我已经重新观看了 10 多次视频，以确保没有语法错误或任何其他事故。基本上，人们在帖子上发布的 cmets 不会保存到数据库中，因此它们不会显示在我展示它们的 html 视图中。我知道他们没有保存，因为我在终端中检查了 cmets 的数据库，它以 0 计数返回。这是我在不同文件中的代码...

ROUTES.RB

Rails.application.routes.draw do
    devise_for :users

    resources :posts do 
        resources :comments
    end

    root 'posts#index'
end

create_cmets 的迁移文件

class CreateComments < ActiveRecord::Migration[5.0]
    def change
        create_table :comments do |t|
            t.text :comment
            t.references :post, foreign_key: true
            t.references :user, foreign_key: true

            t.timestamps
        end
    end
end

cmets_controller.rb

class CommentsController < ApplicationController

    def create
        @post = Post.find(params[:post_id])
        @comment = @post.comments.create(params[:comment].permit(:comment))

        if @comment.save
            redirect_to post_path(@post)
        else
            render 'new'
        end
    end
end

_form.html.haml

= simple_form_for([@post, @post.comments.build]) do |f|
    = f.input :comment
    = f.submit

模型文件注释.rb

class Comment < ApplicationRecord
    belongs_to :post
    belongs_to :user
end

提交表单时记录

Started POST "/posts/2/comments" for ::1 at 2016-09-04 23:00:46 +1000
Processing by CommentsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"/Un6QNWL4BIUbjH5VYMhLRatTq2hokcKnZ3Jb4WzTlvhuZ5AN3gFkA5VHN2E6zsm0iDIx/sKarEfID7Nx4WwwQ==", "comment"=>{"comment"=>"1"}, "commit"=>"Create Comment", "post_id"=>"2"}
  Post Load (0.3ms)  SELECT  "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT ?  [["id", 2], ["LIMIT", 1]]
   (0.1ms)  begin transaction
   (0.1ms)  rollback transaction
Completed 500 Internal Server Error in 26ms (ActiveRecord: 0.5ms)



ActionView::MissingTemplate (Missing template comments/new, application/new with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby, :coffee, :haml, :jbuilder]}. Searched in:
  * "/Users/koz/Desktop/forum/app/views"
  * "/Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/devise-4.2.0/app/views"
):

app/controllers/comments_controller.rb:11:in `create'
  Rendering /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/missing_template.html.erb within rescues/layout
  Rendering /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
  Rendered /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb (14.6ms)
  Rendering /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
  Rendered /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (5.4ms)
  Rendering /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
  Rendered /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (2.9ms)
  Rendered /Users/koz/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/templates/rescues/missing_template.html.erb within rescues/layout (297.8ms)

Answer 1

您的Comment#create 调用失败，因为Comment 模型需要User（belongs_to 关联默认带有存在验证），而您没有设置一个。

要解决它，设置一个用户。

@comment = @post.comments.create(params[:comment].permit(:comment))
@comment.user = current_user

（如果您使用的是 Devise；否则，请通过其他方式找到您的用户）

然后继续你的代码 (@comment.save)。