Не удается создать уведомление для упоминания пользователя At.js?Рельсы 5.2

Question

Я разработал решение, которое позволяет пользователям упоминать друг друга в сообщениях с at.js и отдельным объектом класса, который отслеживает изменения в сообщении.У меня проблема с тем, что я не могу сослаться на упомянутого пользователя, чтобы добавить свой идентификатор в объект уведомления, находясь внутри класса.Он отлично находит пользователя с символом '@', но объект Notification.create () завершается с ошибкой в ​​середине с помощью nil: NilClass.Я не знаю, где разместить уведомление, чтобы получить доступ к current_user и целевому пользователю.Как я могу отформатировать свой код, чтобы получить доступ к current_user в области видимости и о том, что пользователь получает уведомление для объекта Notification?

messages.rb

Ожидаемые значениядля объекта уведомления :

Notification.create(recipient: mentioned.user, actor_id: current_user.id, action: "mentioned you", notifiable: mentioned.user, content: post.body_text.truncate(50).to_s, link_to_content: post.id)

application.js

//= require jquery
//= require jquery.atwho

application.scss

//=require jquery.atwho

application_helper.rb

def markdown(text)
  renderer = Redcarpet::Render::SmartyHTML.new(filter_html: true, 
                                           hard_wrap: true, 
                                           prettify: true)
  markdown = Redcarpet::Markdown.new(renderer, markdown_layout)
  markdown.render(sanitize(text)).html_safe
end

def markdown_layout
  { autolink: true, space_after_headers: true, no_intra_emphasis: true,
    tables: true, strikethrough: true, highlight: true, quote: true,
    fenced_code_blocks: true, disable_indented_code_blocks: true,
    lax_spacing: true }
end

_post.html.erb

<li>
  <span class="content"><%= markdown(post.content) %></span>
  <span class="timestamp">
    Posted <%= time_ago_in_words(post.created_at) %> ago.
  </span>
  <% if current_user?(post.user) %>
    <%= link_to "delete", post, method: :delete,
             data: { confirm: "You sure?" },
             title: post.content %>
  <% end %>
</li>

rout.rb

Rails.application.routes.draw do

  get 'mentions', to: 'users#mentions'
end

users_controller.rb

def mentions
  respond_to do |format|
    format.json { render :json => Mention.all(params[:q]) }
  end
end

posts.coffee

class @Post
  @add_atwho = ->
    $('#post_content').atwho
      at: '@'
      displayTpl:"<li class='mention-item' data-value='(${name},${image})'>${name}${image}</li>",
  callbacks: remoteFilter: (query, callback) ->
    if (query.length < 1)
      return false
    else
      $.getJSON '/mentions', { q: query }, (data) ->
        callback data

jQuery ->
  Post.add_atwho()

post.rb

class Post < ActiveRecord::Base 

  after_create :add_mentions

  def add_mentions
    Mention.create_from_text(self)
  end
end

упоминание.rb

class Mention
  attr_reader :mentionable
  include Rails.application.routes.url_helpers

  def self.all(letters)
    return Mention.none unless letters.present?

    users = User.limit(10).where('username like ?', "#{letters}%").compact
    users.map do |user|
      { image: user.profile.avatar.url(:feed_thumb), name: user.username }
    end
  end

  def self.create_from_text(post)
    potential_matches = post.body_text.scan(/@\w+/i)
    potential_matches.uniq.map do |match|
      mention = Mention.create_from_match(match)
      next unless mention

      post.update_attributes!(body_text: mention.markdown_string(post.body_text))
      # notification fails to save here!
      Notification.create(recipient: @mentionable.user, actor_id: post.user.id, action: "mentioned you", notifiable: @mentionable.user, content: post.body_text.truncate(50).to_s, link_to_content: post.id)
      mention
    end.compact
  end

  def self.create_from_match(match)
    user = User.find_by(username: match.delete('@'))
    UserMention.new(user) if user.present?
  end

  def initialize(mentionable)
    @mentionable = mentionable
  end

  class UserMention < Mention
    def markdown_string(text)
      host = Rails.env.development? ? '127.0.0.1:3000' : 'https://nothing.net' # add your app's host here!
      text.gsub(/@#{mentionable.username}/i,
            "[**@#{mentionable.username}**](#{user_url(mentionable, host: host)})")
    end
  end

конец

ошибка журнала сервера

Started POST "/posts" for 127.0.0.1 at 2019-02-25 16:25:00 -0500
Processing by PostsController#create as JS
  Parameters: {"utf8"=>"✓", "post"=>{"body_text"=>"@cooler Ok. Send this to myself.", "photo_cache"=>""}, "commit"=>"Post"}
  User Load (0.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 2], ["LIMIT", 1]]
  (0.0ms)  BEGIN
  Post Exists (2.0ms)  SELECT  1 AS one FROM "posts" WHERE "posts"."hash_id" = $1 LIMIT $2  [["hash_id", "gai887Te1VwC"], ["LIMIT", 1]]
  Post Create (2.0ms)  INSERT INTO "posts" ("body_text", "user_id", "created_at", "updated_at", "hash_id") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["body_text", "@cooler Ok. Send this to myself."], ["user_id", 2], ["created_at", "2019-02-25 21:25:01.907985"], ["updated_at", "2019-02-25 21:25:01.907985"], ["hash_id", "gai887Te1VwC"]]
  Post Load (0.0ms)  SELECT  "posts".* FROM "posts" WHERE "posts"."id" = $1 LIMIT $2  [["id", 0], ["LIMIT", 1]]
  User Load (1.0ms)  SELECT  "users".* FROM "users" WHERE "users"."username" = $1 LIMIT $2  [["username", "cooler"], ["LIMIT", 1]]
  Post Update (1.0ms)  UPDATE "posts" SET "body_text" = $1, "updated_at" = $2 WHERE "posts"."id" = $3  [["body_text", "[**@cooler**](http://127.0.0.1:3000/u/cooler) Ok. Send this to myself."], ["updated_at", "2019-02-25 21:25:01.919976"], ["id", 71]]
   (1.0ms)  ROLLBACK
Completed 500 Internal Server Error in 92ms (ActiveRecord: 7.0ms)



NoMethodError (undefined method `user' for nil:NilClass):

app/models/mention.rb:21:in `block in create_from_text'
app/models/mention.rb:16:in `map'
app/models/mention.rb:16:in `create_from_text'
app