用户收藏夹-ActivereCord :: AsscocyTypemismatch

Question

已经存在很多问题，但是没有一个完全解决我的问题。

我正在尝试实现一项功能，允许用户从本机构中的答案中"喜欢"的咖啡店"添加到收藏夹"中。在Rails 3＆amp;4.但是，当尝试添加喜欢的人时，我会得到：

ActiveRecord::AssociationTypeMismatch (Coffeeshop(#70266474861840) expected, got NilClass(#70266382630600)):

user.rb

  has_many :coffeeshops
  has_many :favorite_coffeeshops # just the 'relationships'
  has_many :favorites, through: :favorite_coffeeshops, source: :coffeeshop

咖啡馆.rb

  belongs_to :user
  has_many :favorite_coffeeshops # just the 'relationships'
  has_many :favorited_by, through: :favorite_coffeeshops, source: :user

加入关系的新模型

faly_coffeeshops

class FavoriteCoffeeshop < ApplicationRecord
  belongs_to :coffeeshop
  belongs_to :user
end

咖啡馆.show.html.erb

<% if current_user %>
  <%= link_to "favorite",   favorite_coffeeshop_path(@coffeeshop, type: "favorite"), method: :put %>
  <%= link_to "unfavorite", favorite_coffeeshop_path(@coffeeshop, type: "unfavorite"), method: :put %>
<% end %>

咖啡馆_controller.rb

  def favorite
    type = params[:type]
    if type == "favorite"
      current_user.favorites << @coffeeshop
      redirect_to :back, notice: "You favorited #{@coffeeshop.name}"
    elsif type == "unfavorite"
      current_user.favorites.delete(@coffeeshop)
      redirect_to :back, notice: "Unfavorited #{@coffeeshop.name}"
    else
      # Type missing, nothing happens
      redirect_to :back, notice: "Nothing happened."
    end
  end

我意识到最初的问题是基于Rails 3/4，而我在5中，所以也许现在我的代码已经过时了。

解决方案

咖啡馆_controller.rb

  def favorite
    @coffeeshop = Coffeeshop.find(params[:id]) #<= Added this
    type = params[:type]
    if type == "favorite"
      current_user.favorites << @coffeeshop
      redirect_to :back, notice: "You favorited #{@coffeeshop.name}"
    elsif type == "unfavorite"
      current_user.favorites.delete(@coffeeshop)
      redirect_to :back, notice: "Unfavorited #{@coffeeshop.name}"
    else
      # Type missing, nothing happens
      redirect_to :back, notice: "Nothing happened."
    end
  end

Answer 1

@coffeeshop是null，您应该使用用户想要喜欢的一个初始化它(例如从 params[:id]检索(