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第一次在这里发帖，所以我希望它是有道理的，但是我在这方面已经旋转了太久了。首先是一点背景。我正在构建一个具有 3 个模型的 Wiki 应用程序：用户、Wiki 和协作（连接表）。

我正在使用 Devise 和 Pundit，并且有 4 类用户应该根据他们的状态查看不同的 wiki 子集。

这是规则：

  • 公共用户（未登录）- 只应查看（无编辑）公共 wikis (:hide => false)
  • Authenticated User(:role => "standard") - 只能查看、编辑和删除公共 wiki。
  • 高级用户 (:role => "premium") - 查看、编辑、删除公共 wiki 以及创建私人 wiki 的能力 (:hide => true) 并将协作者添加到他们的私人 wiki 中，从而赋予他们对该 wiki 的编辑权限。
  • 管理员 (:role => "admin") 完全控制所有记录。

因此，我的 Wiki 索引视图在 Policy 范围（检查用户状态）中有一个冗长的 scope.joins 条件，以便根据他们的角色为 current_user 提供一个 wiki 列表的子集。

它不断吐出这个错误：

Started POST "/__better_errors/59802a57d82fd17e/variables" for 127.0.0.1 at 2014-12-02 09:05:41 -0800
  Wiki Load (0.4ms)  SELECT "wikis".* FROM "wikis" INNER JOIN "collaborations" ON "collaborations"."wiki_id" = "wikis"."id" WHERE (hide = 'f' or user_id = 2 or collaborations.user_id = 2)
SQLite3::SQLException: ambiguous column name: user_id: SELECT "wikis".* FROM "wikis" INNER JOIN "collaborations" ON "collaborations"."wiki_id" = "wikis"."id" WHERE (hide = 'f' or user_id = 2 or collaborations.user_id = 2)

这是政策

class WikiPolicy < ApplicationPolicy

  # What collections a user can see users `.where` 
  class Scope < Scope

    def resolve
      if user && user.role == 'admin'
        scope.all 
      elsif user
        scope.joins(:collaborations).where("hide = :hide or user_id = :owner_id or collaborations.user_id = :collaborator_id", {hide: false, owner_id: user.id, collaborator_id: user.id})
      else 
        scope.where hide: false
      end
    end
  end


  #Policies are boolean logic true or false to determine if a user has access to a controller action.
  def update?
    (user && user.role == 'admin') || (user && record.users.pluck(:id).include?(user.id)) || (user && user.id == record.owner.id )
  end

  def show?
    (user.present? && user.admin?) or not record.hide?
  end

  def premium?
    user.admin? or user.premium?
  end

  def edit?

  end

end

我的模型

class Wiki < ActiveRecord::Base
  belongs_to :user
  has_many :collaborations, dependent: :destroy
  has_many :users, through: :collaborations

  def owner
    user
  end

  def collaborators
    users
  end

  validates :title, length: { minimum: 5 }, presence: true
  validates :body, length: { minimum: 20 }, presence: true

end

class User < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable, :confirmable
  has_many :wikis
  has_many :collaborations 
  has_many :cowikis, through: :collaborations, source: :wiki

  after_initialize :init

  def admin?
    role == 'admin'
  end

  def premium?
    role == 'premium'
  end

  def standard?
    role == 'standard'
  end

private
  def init
    if self.new_record? && self.role.nil?
      self.role = 'standard'
    end
  end
end

 class Collaboration < ActiveRecord::Base
  belongs_to :user
  belongs_to :wiki
end

维基控制器 

class WikisController < ApplicationController
  def index
   @wikis = policy_scope(Wiki)  
    # authorize @wikis
  end

  def show
    @wiki = Wiki.find(params[:id])
    authorize @wiki
  end

  def new
    @wiki = Wiki.new
    authorize @wiki
  end

  def create
    @wiki = Wiki.new(wiki_params)
    authorize @wiki
    if @wiki.save
      flash[:notice] = "Post was saved."
      redirect_to @wiki
    else
      flash[:error] = "There was an error saving the post. Please try again."
      render :new
    end
  end

  def edit
    @user = current_user
    @users = User.all
     @wiki = Wiki.find(params[:id])
     authorize @wiki
  end

 def update
   @wiki = Wiki.find(params[:id])
   authorize @wiki
   @wiki.collaborators = params[:wiki][:user_ids]
   if @wiki.update_attributes(wiki_params)
     flash[:notice] = "Post was updated."
     redirect_to @wiki
   else
     flash[:error] = "There was an error saving the post. Please try again."
     render :edit
   end
 end

  def destroy
    @wiki = Wiki.find(params[:id])
    authorize @wiki
    title = @wiki.title

    if @wiki.destroy
      flash[:notice] = "\"#{title}\" was deleted successfully."
      redirect_to wikis_path
    else
      flash[:error] = "There was an error deleting the wiki."
      render :show
    end
  end

  private

   def wiki_params
     params.require(:wiki).permit(:title, :body, :hide)
   end
end

我希望你不会被代码淹没，但我想提供尽可能多的信息。

谢谢你的帮助！

哦，这很可能是有问题的代码，但我将其他所有内容都包含在上下文中。

scope.joins(:collaborations).where("hide = :hide or user_id = :owner_id or collaborations.user_id = :collaborator_id", {hide: false, owner_id: user.id, collaborator_id: user.id})
4

1 回答 1

1

这是错误消息中最有价值的部分：

SQLite3::SQLException: ambiguous column name: user_id

当 SQL 结果集有多个同名的列时，可能会发生列名不明确的错误。在这种情况下，列是user_id。

该user_id列位于 wikis 表和协作表上。这两个表都在 SQL 查询中使用。

这是导致问题的 SQL 片段：

# DB can't figure out which table "user_id = 2" refers to:
WHERE (hide = 'f' or user_id = 2 or collaborations.user_id = 2)

我们需要在该user_id列上指定一个表名前缀。

为此，请尝试将这一行更改WikiPolicy为：

scope.joins(:collaborations)
    .where("hide = :hide or user_id = :owner_id or collaborations.user_id = :collaborator_id", {hide: false, owner_id: user.id, collaborator_id: user.id})

到：

scope.joins(:collaborations)
    .where("hide = :hide or wikis.user_id = :owner_id or collaborations.user_id = :collaborator_id", {hide: false, owner_id: user.id, collaborator_id: user.id})
于 2014-12-02T17:51:03.250 回答