嵌套路由和 CRUD 操作以及 Rails 中关联的附加值 [英] Nested routes and CRUD operations with additional values for assciation in Rails

问题描述

我通过 rails api 中的关系创建了一个 has_many.我还使用了嵌套路由.

我的模型如下；

class Author :注释结尾课后:注释结尾班级评论ActiveRecord::Base归属地:作者归属地:发布结尾

我的路线如下；

Rails.application.routes.draw 做命名空间:api，默认值:{ :format =>'json' } 做资源:帖子做资源:评论结尾资源:作者结尾结尾

所以我的目标是

<块引用>

1. 评论是嵌套路由，以便我可以从帖子中创建和显示评论
2. 这里不是任何帖子作者.作者是为评论所有者准备的

我实现了几乎所有的概念和工作.但是我面临以下两个关联问题

1. 如何在父级创建时为关联表添加其他字段.我的要求是在创建帖子时，我需要插入一个默认条目以进行评论.我的创建后控制器实现如下

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def 创建params = create_params.merge(:record_status => 1)@post = Post.new(params)@post.authors <<作者.find(1)如果@post.save渲染:显示，状态::创建结尾结尾高清秀@post = Post.find(params[:id])结尾私人的def create_paramsparams.permit(:name, :description, :author_id)结尾

这里我在请求 json 中传递 author_id.这需要在评论表中添加为作者 ID.现在我只是硬编码为 1.我使用了 '<<'用于关联条目.这是有效的，但我还需要包括另外两个字段:comments 和:record_status.再次:评论来自请求本身.

注意:这不是 rails mvc 应用程序.这是rails api，输入为json.

2. 当我使用嵌套路由显示评论时，我需要显示作者以及评论表中的评论.我的评论控制器方法是 ;

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class Api::CommentsController <应用控制器before_filter :fetch_post定义索引@authors = @post.authors.where(:record_status => 1, 评论:{ record_status: 1 })结尾私人的def fetch_post@post = Post.find(params[:post_id])结尾结尾

在这里我得到了作者，但在连接表评论"中没有正确的评论

请帮我解决这些问题

解决方案

对于第一个问题，您要配置 posts_controller 以接受评论的嵌套属性.在控制器的开头添加这一行:

accepts_nested_attributes_for :comments

查看文档了解更多详情在这个方法上.

然后，您需要修改控制器允许的参数:

def create_paramsparams.permit(:name, :description, :author_id, comments_attributes: [ :author_id, :comments, :record_status ] )结尾

修改 comments_attributes 数组中列出的属性以匹配您的 Comment 模型的属性.

我不确定你想在第二个问题中得到什么，但也许你只需要稍微不同的查询:

@comments = Comment.where(post_id: @post.id).includes(:author)

以上将返回包括评论作者在内的评论列表.

I created one has_many through relationship in rails api. I also used nested routes.

My models like below;

class Author < ActiveRecord::Base
 has_many :comments
 has_many :posts, :through => :comments
end

class Post < ActiveRecord::Base
 has_many :comments
 has_many :authors, :through => :comments
end

class Comment < ActiveRecord::Base
 belongs_to :author
 belongs_to :post
end

my routes like below;

Rails.application.routes.draw do
 namespace :api, defaults: { :format => 'json' } do
  resources :posts do
   resources :comments
  end
  resources :authors
 end
end

So here my aims are

1. Comments are nested route so that i can create and display comments from post
2. Here not any post author. The author is meant for comment owner

I implemented the concepts and working almost all. But i am facing the following 2 problems with associations

1. How to add additional fields for associated table when parent create. Here my requirement is when a post is created, i need to insert one default entry for comment. My post controller implementation for create is like below

def create
  params = create_params.merge(:record_status => 1)
  @post = Post.new(params)
  @post.authors << Author.find(1)
  if @post.save 
   render :show, status: :created
  end
 end

 def show
  @post = Post.find(params[:id])
 end

private
def create_params
 params.permit(:name, :description, :author_id )
end

Here i am passing author_id in the request json. This needs to be added as author id in the comments table. Now i just hard coded as 1. I used '<<' for association entry. This is working but i also need to include two more fields which are :comments and :record_status. Again :comments is from the request itself.

Note: This is not rails mvc application. This is rails api and input as json.

2. When i display comments using nested routes i need to show author and also comments from comments table. My comments controller method is ;

class Api::CommentsController < ApplicationController
 before_filter :fetch_post

 def index
    @authors = @post.authors.where(:record_status => 1, comments: { record_status: 1 })
end

private

def fetch_post
 @post = Post.find(params[:post_id])
end

end

Here i got authors but not correct comments in the join table 'comments'

Please help me to solve these issues

解决方案

For the first problem, you want to configure the posts_controller to accept the nested attributes for comments. Add this line at the beginning of your controller:

accepts_nested_attributes_for :comments

Check the documentation for further details on this method.

Then, you need to modify the parameters that the controller will allow:

def create_params
 params.permit(:name, :description, :author_id, comments_attributes: [ :author_id, :comments, :record_status ] )
end

Modify the attributes listed in the comments_attributes array to match those of your Comment model.

I'm not sure what you're trying to get in the second problem, but maybe you just need to query a little differently:

@comments = Comment.where(post_id: @post.id).includes(:author)

The above would return a list of comments including the comment author.

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