如何设置基于多个模型的条件？

Question

通知/索引有<%= render partial: "notifications/notification", collection: @notifications %>，其中包含：

<% if Comment.find_by(notification.comment_id) == @habit %>
  <%= link_to "your habit", habit_path(notification) %>
<% else %>
  <%= link_to "your value", valuation_path(notification) %>
<% end %>

显示第一行的错误：

找不到“id”= 的习惯

即使控制台显示：

pry(main)> Comment.find(1)
  Comment Load (0.3ms)  SELECT  "comments".* FROM "comments" WHERE "comments"."id" = ? LIMIT 1  [["id", 1]]
=> #<Comment:0x007f86201267b0
 id: 1,
 content: "test",
 goal_id: nil,
 habit_id: 1,
 valuation_id: nil,
 quantified_id: nil,
 commentable_id: nil,
 commentable_type: nil,
 user_id: 1,
 created_at: Thu, 04 Jun 2015 00:07:22 UTC +00:00,
 updated_at: Thu, 04 Jun 2015 04:04:29 UTC +00:00,

我们如何使用条件让每个通知都指向正确的路径？

notifications_controller

def index
  @habit = Habit.find(params[:habit_id])
  @notifications = current_user.notifications
  @notifications.each do |notification|
    notification.update_attribute(:read, true)
  end
end

通知基于用户是否符合习惯或价值观：

comment.rb

class Comment < ActiveRecord::Base
  after_save :create_notification
  has_many :notifications
  belongs_to :commentable, polymorphic: true
  belongs_to :user
  validates :user, presence: true

private

  def create_notification
      Notification.create(
       user_id: self.user_id,
       comment_id: self.id,
       read: false
      )
  end
end

我遵循了这个通知教程，但它只基于一个模型：http://evanamccullough.com/2014/11/ruby-on-rails-simple-notifications-system-tutorial/

cmets_controller

class CommentsController < ApplicationController
  before_action :set_commentable, only: [:index, :new, :create]
  before_action :set_comment, only: [:edit, :update, :destroy, :like]

  def index
    @comments = @commentable.comments
  end

  def new
    @comment = @commentable.comments.new
  end

  def create
    @comment = @commentable.comments.new(comment_params)
    if @comment.save
      redirect_to @commentable, notice: "Comment created."
    else
      render :new
    end
  end

  def edit
  end

  def update
    if @comment.update_attributes(comment_params)
      redirect_to :back, notice: "Comment was updated."
    else
      render :edit
    end
  end

  def destroy
    @comment.destroy
    redirect_to @comment.commentable, notice: "Comment destroyed."
  end

  def like
    @comment_like = current_user.comment_likes.build(comment: @comment)
    if @comment_like.save
      @comment.increment!(:likes)
      flash[:success] = 'Thanks for liking!'
    else
      flash[:error] = 'Too many likes'
    end  
    redirect_to(:back)
  end

  private

  def set_commentable
    @commentable = find_commentable
  end

  def set_comment
    @comment = current_user.comments.find(params[:id])
  end

  # add more commentable models here
  def find_commentable
    if params[:goal_id]
      Goal.find(params[:goal_id])
    elsif params[:habit_id]
      Habit.find(params[:habit_id])
    elsif params[:valuation_id]
      Valuation.find(params[:valuation_id])
    elsif params[:quantified_id]
      Quantified.find(params[:quantified_id])
    end
  end

  def comment_params
    params[:comment][:user_id] = current_user.id
    params.require(:comment).permit(:content, :commentable, :user_id, :like)
  end
end

Answer 1

首先，根据 MVC，您不应该在视图中进行 SQL 查询：

<% if Comment.find_by(notification.comment_id) == Habit.find(params[:habit_id]) %> 不好的做法！

您应该在控制器中进行查询，然后在视图中使用控制器的实例变量（带有@的变量）。

其次，params[:habit_id] 仅在您的 url 有参数“habit_id”时才有效：?habit_id=[id] 但由于您的视图不应该进行任何查询，因此您应该先更改它。