Question

我有一个用户和文章模型，用户可以拥有许多模型，并将删除功能限制为用户或管理员。然而，当我试图破坏文章时，我收到以下错误：

未定义的方法`user'代表nil：NilClass

并指向我的文章控制器中的这个私有函数：

def require_same_user
    if current_user != @article.user and !current_user.admin?
        flash[:danger] = "You can only edit or delete your own articles"
        redirect_to root_path
    end
end

这是我的整个控制器文件：

class ArticlesController < ApplicationController
before_action :set_article, only: [:edit, :update, :show]
before_action :require_user, except: [:index, :show]
before_action :require_same_user, only: [:edit, :update, :destroy]

def index 
    @articles = Article.paginate(page: params[:page], per_page: 5)
end

def show 

end

def new
    @article = Article.new
end

def edit 

end

def update
    @article.update(article_params)
    if @article.save
        flash[:success] = "Article successfully updated!"
        redirect_to article_path(@article)
    else
        flash[:danger] = "Sorry, try again..."
        render :edit
    end
end

def create 
    @article = Article.new(article_params)
    @article.user = current_user
    if @article.save
        flash[:success] = "New article created"
        redirect_to articles_path
    else
        flash[:danger] = "Sorry, invalid values"
        render :new
    end
end

def destroy
    @article = Article.find(params[:id])
    @article.destroy
    flash[:success] = "Article deleted"
    redirect_to articles_path
end

private

def article_params
    params.require(:article).permit(:name, :title, :description)
end

def set_article
    @article = Article.find(params[:id])
end

def require_same_user
    if current_user != @article.user and !current_user.admin?
        flash[:danger] = "You can only edit or delete your own articles"
        redirect_to root_path
    end
end

端

文章和用户存在于db中，这可能是什么？提前谢谢

Answer 1

您使用set_article功能设置文章，但在require_same_user功能的情况下，它不知道{{1}的值是什么1}};所以在这种情况下，值为nil，因为它不在范围内，也不是之前创建的实例变量。

@article

一种方法可能是将def require_same_user # Here there's no @article, so it's evaluated as nil, # and nil doesn't have a method user. if current_user != @article.user ... ...设置为在set_article执行之前执行。

require_same_user

您还可以将代码分成较小的部分，以便在需要时再次使用：

before_action :set_article, only: %i[edit update show require_same_user]

Answer 2

确保在destroy操作之前运行before_action :set_article, only: [:edit, :update, :show, :destroy]。

在您的控制器中：

{"name":"asfd","username":"awsf","email":"kean","age":"21","gender":"Male","submit":"Submit"},
{"name":"asdf","username":"asfd","email":"asdf@asdf","age":"21","gender":"Male","submit":"Submit"},
{"name":"null","username":"null","email":"null@gmail.com","age":"21","gender":"Male","submit":"Submit"},
{"name":"null","username":"null","email":"null@gmail.com","age":"21","gender":"Male","submit":"Submit"},

Ruby on Rails：销毁函数而不删除项

2 个答案: