显示部分记录计数记录

Question

我有一个ruby应用程序，我有帖子和类似的模型。我想能够点击一个像按钮，然后刷新帖子的喜欢数量。为此，我正在使用ajax。

我的问题是我如何计算我的部分HTML文档中的帖子的喜欢。目前，我的_show.html.erb中的代码如下所示：

<%= @post.likes.all.count %>

我想在index.html.erb中显示代码的div看起来像这样：

<div>
        Likes: <div id="<% post.id %>_likes_output", local: :post></div>
</div>

我的create.js.erb看起来像这样：

$(document.getElementById("<%@post%> _likes_output").innerHTML = "<%= render partial: "likes/show", local: :post %>");

My Like create方法如下所示：

def create
  @user = current_user.id
  @post = params[:post_id]
  likes = {user_id: @user, post_id: @post}
  @like = Like.new(likes)

  # a new entry in the likes table gets created
  if @like.save!
  else
    flash[:alert] = "Something went wrong"
  end
end 

目前我收到以下错误：

Started POST "/posts/13/likes" for ::1 at 2019-03-22 11:38:28 +0100
Processing by LikesController#create as JS
  Parameters: {"post_id"=>"13"}
  User Load (0.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ↳ app/controllers/likes_controller.rb:4
   (0.0ms)  begin transaction
  ↳ app/controllers/likes_controller.rb:10
  Post Load (0.2ms)  SELECT  "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT ?  [["id", 13], ["LIMIT", 1]]
  ↳ app/controllers/likes_controller.rb:10
  User Load (0.1ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ↳ app/controllers/likes_controller.rb:10
  Like Create (0.3ms)  INSERT INTO "likes" ("created_at", "updated_at", "user_id", "post_id") VALUES (?, ?, ?, ?)  [["created_at", "2019-03-22 10:38:28.067946"], ["updated_at", "2019-03-22 10:38:28.067946"], ["user_id", "1"], ["post_id", "13"]]
  ↳ app/controllers/likes_controller.rb:10
   (1.0ms)  commit transaction
  ↳ app/controllers/likes_controller.rb:10
  Rendering likes/create.js.erb
  Rendered likes/_show.html.erb (21.0ms)
  Rendered likes/create.js.erb (38.8ms)
Completed 500 Internal Server Error in 91ms (ActiveRecord: 1.8ms)



ActionView::Template::Error (undefined method `likes' for "13":String
Did you mean?  lines):
    1: <%= @post.likes.all.count %>

app/views/likes/_show.html.erb:1:in `_app_views_likes__show_html_erb___2777362880017156755_70224479796840'
app/views/likes/create.js.erb:3:in `_app_views_likes_create_js_erb__712898782247662482_70224408518740'

如果您还有其他需要，请告诉我。非常感谢！

Answer 1

@ flo3719你的代码中可能还有其他问题，但你提到ActionView::Template::Error (undefined method 'likes' for "13":String的问题是由于罪魁祸首线@post = params[:post_id]，由于这条线你的@post对象在视图中包含"13"。

您应该使用以下命令从数据库中找到您的帖子：

@post = Post.find_by_id(params[:post_id])

用以下代码替换你的@post = params[:post_id]

@post = Post.find_by_id(params[:post_id])

Answer 2

看来你的@post是一个字符串。这里

@post = params[:post_id]

应该

@post = Post.find(params[:post_id])

Answer 3

你应该找到你的帖子而不是传递id：

@post = Post.find(params[:post_id])

另外，考虑使用counter_cache存储喜欢的数量 - 在性能方面要好得多！ https://guides.rubyonrails.org/association_basics.html#options-for-belongs-to-counter-cache