javascript - 显示部分统计的记录

Question

我有一个 ruby​​ 应用程序，我在其中发布和喜欢模型。我希望能够单击一个赞按钮，然后刷新该帖子的赞数。为此，我正在使用 ajax。

我的问题是如何在我的部分 html 文档中计算帖子的点赞数。目前我的 _show.html.erb 中的代码如下所示:

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

我想在其中显示 index.html.erb 中的代码的 div 如下所示:

<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 %>");

我的 Like 创建方法如下所示:

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'

如果您还需要什么，请告诉我。非常感谢!

Answer 1

@flo3719 您的代码中可能存在其他问题，但您提到的问题 ActionView::Template::Error (undefined method 'likes' for "13":String is due to the culprit行 @post = params[:post_id]，由于这一行，您的 @post 对象在 View 中包含 "13"。

您应该使用以下方法从数据库中找到您的帖子:

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

用下面的代码替换你的@post = params[:post_id]

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