Question

I have model User. And one of controller methods is

 def view_messages
    @user = User.find(params[:id])
    @message=Message.new
    @messages=@user.messages.reverse
  end

Also i have model Message , and one of parametres of this model is user_from:integer

view_messages view have

render :partial => 'messages/message', :collection => @messages

and _message.haml have

= content_tag_for(:li,message) do
  %p
    From:
    =link_to User.find(message.user_from).name,User.find(message.user_from)

it writes an error

Couldn’t find User without an ID

but if i want to print it like

 = content_tag_for(:li,message) do
      %p
        From:
        =message.user_from

it print it ( for exaple it prints 2) , so why it cant find user with id 2 if i have this user? What i am doing wrong?
Thanks in advance

Answer 1

General issues:

1. user_from should be user_from_id, by Rails convention

2. Then you should have a belongs_to relation:

   class Message
     belongs_to :user_from
   end
   

   which will automatically pull the user from the database

3. Then you can refer to the user as an attribute of Message

   link_to @message.user_from.name, @message.user_from
   

Check all of the Message records. One of them probably has no user_from, and causes the error.