（对于nil：NilClass，未定义方法`receipts_for'-MailBoxer Gem Rails

Question

I'm using the mailboxer gem to build a messaging system between users for my rails application. For some reason, I'm getting this error:

(undefined method `receipts_for' for nil:NilClass)

Maybe it's because I should define 'receipts_for' somewhere in my controller or in the mailboxer.rb? I tried a few things.. but unfortunately none of them were successful.

This is my routes.rb:

 Rails.application.routes.draw do root 'static_pages#home' get '/help', to: 'static_pages#help' get '/about', to: 'static_pages#about' get '/contact', to: 'static_pages#contact' get '/signup', to: 'users#new' get '/login', to: 'sessions#new' get 'search/index' post '/login', to: 'sessions#create' delete '/logout', to: 'sessions#destroy' resources :users do member do get :following, :followers end end resources :conversations do resources :messages end resources :account_activations, only: [:edit] resources :password_resets, only: [:new, :create, :edit, :update] resources :microposts, only: [:create, :destroy] resources :relationships, only: [:create, :destroy] resources :searches end 

This is my conversations controller:

 class ConversationsController < ApplicationController def show @conversation = current_user.mailbox.conversation.find(params[:id]) end def new @recipients = User.find(params[:user_id]) end def create recipient = User.find(params[:user_id]) receipt = current_user.send_message(recipient, params[:body]) redirect_to conversation_path(receipt.conversation) end end 

This is my messages_controller:

 class MessagesController < ApplicationController before_action :set_conversation def create receipt = current_user.send_message(@conversation, body) redirect_to receipt.conversation end private def set_conversation @conversation = current_user.mailbox.conversations.find(params[:conversation_id]) end end 

The messaging system I'm building precisely, is a messaging system where the 'current_user' can go to the profile page of any user on the application and message him/her via the profile page. So this means that I'm rendering show.html.erb of the conversation model inside the show.html.erb of my users model. Here is the code of both views:

show.html.erb - Users Model:

 <% provide(:title, @user.name) %> <div class="row"> <aside class="col-md-4"> <section> <h1> <%= gravatar_for @user %> <%= @user.name %> </h1> </section> <section class="stats"> <%= render 'shared/stats' %> </section> <h6> <%= @user.gender %> </h6> <%= render "conversations/conversation" %> </aside> <div class="col-md-8"> <%= render 'follow_form' if logged_in? %> <% if @user.microposts.any? %> <h3>Microposts (<%= @user.microposts.count %>)</h3> <ol class="microposts"> <%= render @microposts %> </ol> <%= will_paginate @microposts %> <% end %> </div> </div> 

_conversation.html.erb - show view of the conversations model.

 <% @conversation.receipts_for(current_user).each do |receipt| %> <div> <%= receipt.message.body %> </div> <% end %> <%= form_tag conversation_messages_path(@conversation), method: post do %> <div> <%= text_area_tag :body %> </div> <%= submit_tag %> <% end %> 

So how exactly can I define the 'receipts_for' method for my mailboxer? Or is something else wrong with my code?

Any help would be much appreciated!

Thanks!

Answer 1

I'll piggy-back on what @mu is too short said. It's important to pay attention to the whole error message. “undefined method receipts_for for nil:NilClass” is telling you that the receiver of the receipts_for method is nil. @conversation.receipts_for(current_user) looks to be the only place where receipts_for is used, so I would start debugging by making sure @conversation is assigned the value of an existing ActiveRecord-backed conversation object.

There seems to be too a lot going on, so I don't know how to offer you a quick fix. The value assignment in your ConversationsController#show method, @conversation= current_user.mailbox.conversation.find(params[:id]) looks cumbersome. That suggests to me that you're looking for a conversation based on a mailbox belonging to the current_user , which might be what you want (in which case, you need to have the appropriate associations defined in your models).

However, since the chain ends with conversation.find(params[:id]) , I'm guessing that current_user.mailbox is not needed. Alternatively, if your params don't actually have a conversation id, then maybe that's what you need to focus on.

The good news is you can probably figure out how to define @conversation if you stick byebug (or binding.pry , depending on what you have installed) at the top of your show method and in your view partial:

# In the controller:

  def show
    binding.pry
    @conversation = current_user.mailbox.conversation.find(params[:id])
  end


# in the view
<% binding.pry %>