Rails:臭名昭著的“current_user"在哪里?来自?

问题描述

我最近一直在浏览 Rails，注意到有很多对 current_user 的引用.这仅来自Devise吗?即使我使用 Devise，我是否必须自己手动定义它?使用 current_user 是否有先决条件(例如会话、用户等的存在)?

I've been looking around recently into Rails and notice that there are a lot of references to current_user. Does this only come from Devise? and do I have to manually define it myself even if I use Devise? Are there prerequisites to using current_user (like the existence of sessions, users, etc)?

推荐答案

它由几个 gem 定义，例如设计

It is defined by several gems, e.g. Devise

您需要将 user_id 存储在某处，通常是在登录后的会话中.它还假设您的应用拥有并需要用户、身份验证等.

You'll need to store the user_id somewhere, usually in the session after logging in. It also assumes your app has and needs users, authentication, etc.

通常，它类似于:

class ApplicationController < ActionController::Base
  def current_user
    return unless session[:user_id]
    @current_user ||= User.find(session[:user_id])
  end
end

这假设 User 类存在，例如#{Rails.root}/app/models/user.rb.

This assumes that the User class exists, e.g. #{Rails.root}/app/models/user.rb.

更新:当没有当前用户时避免额外的数据库查询.

Updated: avoid additional database queries when there is no current user.

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