gem devise how to add comment created user email?

问题

I am using gem devise for creating users profile Each user can create a comment. I need to add the user name beside each comment something like this <%= @comment.user.name %>

in user.rb

  has_many :comments, dependent: :destroy

in comment.rb

  belongs_to :users

in comment controller

before_action :find_comment ,only:[:show,:update,:edit,:destroy]

   def new
    @user =User.find(params[:id])
    @comment = @user.comments.build
  end

  def create
    @user =User.find(params[:id])
    @comment = @user.comments.build(comment_params)
    @comment.user = current_user
    if @comment.save
      redirect_to doctor_path(:id => @user.id)
    end
  end

private

  def find_comment
    @comment = Comment.find(params[:id])
  end

  def comment_params
    params.require(:comment).permit(:text)
  end

user controller

  def show
    @user = User.find(params[:id])
  end

user show.html.erb

<% for item in @user.comments %>
  <% if item.text.present? %>
    <%= item.text %><br>        
    <%= @comment.user.name %>
    <br><hr>
  <% end %>

I got this error

undefined method `user' for nil:NilClass

回答1:

You could do it the other way around, in your show method:

@comments = Comment.all

in your show view:

<% @comments.each do |comment| %>
  <%= comment.text %>
  <%= comment.user.name %>
<% end %>

Since your question is not really clear I'll specifiy that if you want to show just the comments posted by the user:

def show
  user_id = User.find(params[:id]).id
  @comments = Comment.where(user_id: user_id)
end

回答2:

Just some quick rules to start with

A user has many comments, this will be the relationship between the user and a comment that the user has made. You already have this
A user has many profile comments, this is the relationship between a user and the comments that have been left for that user on their profile

Now you have that distinction things start to be come clearer.

Start by creating a single xref table to act as the go between users and comments that have been left for a profile and call it profile_comments this profile_comments table needs a user_id and a comment_id of type integer to store the primary keys from user and comments tables, where the user_id is the id of the user that is having a comment left about them on their profile

You can now setup a profile_comment model that with the following relationships

belongs_to comment
belongs_to user

So now you need to change your user model relationships to the following

user.rb

  has_many :comments
  has_many :profile_comments, dependent: :destroy

comment.rb

  belongs_to :user #not users as you have defined in your question
  has_many :profile_comments, dependent: :destroy

and the new profile_comment.rb model needs the two belongs_to clauses for comment and user

profile_comment.rb

belongs_to :user
belongs_to :comment

Now when you create a comment you need to assign to to the user, and also to the profile_comment

So now your comments controller needs to setup these relationships so instead of

before_action :find_comment ,only:[:show,:update,:edit,:destroy]

   def new
    @user =User.find(params[:id])
    @comment = @user.comments.build
  end

  def create
    @user =User.find(params[:id])
    @comment = @user.comments.build(comment_params)
    @comment.user = current_user
    if @comment.save
      redirect_to doctor_path(:id => @user.id)
    end
  end

You need something like this

  def create
    @user =User.find(params[:id])
    @comment = current_user.comments.build(comment_params)
    @profile_comment = ProfileComment.new
    @user.profile_comment < @profile_comment
    @comment.profile_comment < @profile_comment
    if @comment.save
      redirect_to doctor_path(:id => @user.id)
    end
  end

Your update action will need to also change accordingly

Now in your view instead of

<% for item in @user.comments %>
  <% if item.text.present? %>
    <%= item.text %><br>        
    <%= @comment.user.name %>
    <br><hr>
  <% end %>
<% end %>

You want this, it's a little complex because you need to get from the profile comment to the comment then to the user that created the comment

<% @user.profile_comments.each do | profile_comment |%>
  <%comment = profile_comment.comment%>
  <% if comment.text.present? %>
    <%= comment.text %><br>
    <%if comment.user.blank?%>
      No user assigned to this comment
    <%else%>
      <%= comment.user.name #or email or whatever%>
    <%end%>
    <br><hr>
  <% end %>
<% end %>

Although text is a reserved word and is an actual column type so you might want to change the column name text to something else

Any questions on this feel free to get back to me but I won't be around for the next 24 hours. Hope it's clear and helps you understand what has gone wrong with your initial setup

In the controller and the view I have assumed that the current_user is the person making the comment and @user is the person that is being commented on. Just switch that round if I have that wrong

来源：https://stackoverflow.com/questions/62886524/gem-devise-how-to-add-comment-created-user-email

标签

ruby-on-rails

database

authentication

devise

comments