如何使用Rails在Twitter风格的应用程序中实现此直接消息传递功能？

Question

我正在尝试使用Rails实现与Twitter非常相似的直接消息传递功能，我想知道我在这里做错了什么。我试图限制用户关注的关注者和用户的直接消息传递，但我只能限制直接消息传递给关注者，但由于某种原因无法为用户关注的用户添加此功能。

这是相关代码：app/controllers/messages_controller.rb

class MessagesController < ApplicationController
  before_action :signed_in_user
  before_action :find_user_id, only: :create

def create
    @message = current_user.messages.build(message_params)
    @message.recipient_id = @recipient.id
    if @message.save
      flash[:success] = "You successfully sent a message to #{@message.recipient.username}!"
      redirect_to messages_path
    else
      flash[:error] = "There was an error sending your message, try again!"
      redirect_to messages_path
    end
  end

 private

  def message_params
    params.require(:message).permit(:recipient_id, :content)
  end

  def find_user_id
    username = params[:message][:recipient].downcase
    @recipient = User.where('lower(username) = ?', username).first
    if @recipient.nil?
      flash[:error] = "Invalid username"
      redirect_to messages_path
    elsif @recipient.following?(current_user) == nil || @recipient.follower?(current_user) == nil
      flash[:error] =
          "You can only direct message followers or users you are following"
      redirect_to messages_path
    end
  end
end

问题区域似乎是这行代码：

elsif @recipient.following?(current_user) == nil || @recipient.follower?(current_user) == nil

elsif @recipient.following?(current_user) == nil works properly, but the latter code doesn't.  The code from those two lines are from: app/models/user.rb

  def follower?(other_user)
    relationships.find_by(follower_id: other_user.id)
  end

  def following?(other_user)
    relationships.find_by(followed_id: other_user.id)
  end

如果有人可以帮助我或建议对此问题进行一些可能的修复，我们将不胜感激。如果您需要更多信息来理解代码或解决问题，请不要犹豫！

以下是了解其背后数据模型的其他信息：

在db / migrate文件夹中：

class CreateRelationships < ActiveRecord::Migration
  def change
    create_table :relationships do |t|
      t.integer :follower_id
      t.integer :followed_id

      t.timestamps
    end
    add_index :relationships, :follower_id
    add_index :relationships, :followed_id
    add_index :relationships, [:follower_id, :followed_id], unique: true
  end
end

同样在同一目录中：

class CreateMessages < ActiveRecord::Migration
  def change
    create_table :messages do |t|
      t.integer :sender_id
      t.integer :recipient_id
      t.string  :content

      t.timestamps
    end
    add_index :messages, [:sender_id, :recipient_id, :content]
  end
end

谢谢。