Rails 5：will_paginate gem 分页重复 objects（ID 1-10 等的 100 objects）。

Question

我在我的应用程序上安装了 will_paginate 版本 3.1.5，它正在做一些奇怪的事情。

我正在尝试分页 Books。我在 books_controller:

中设置了这样的分页

def index
  @books = Book.paginate(page: params[:page], per_page: 10)
  respond_to do |format|
    format.html
    format.js
  end
end

但是当我访问那个页面时，我注意到终端没有像它应该的那样查询 10 本书：

Started GET "/" for ::1 at 2017-05-16 10:28:47 -0700
Processing by BooksController#index as HTML
  Rendering books/index.html.erb within layouts/application
  Book Load (1.1ms)  SELECT  "books".* FROM "books" LIMIT  OFFSET   [["LIMIT", 10], ["OFFSET", 0]]
  Rendered collection of books/_book.html.erb [10 times] (291.7ms)
   (0.6ms)  SELECT COUNT(*) FROM "books"
  Rendered books/index.html.erb within layouts/application (389.9ms)
Completed 200 OK in 880ms (Views: 849.9ms | ActiveRecord: 1.7ms)

如果我检查 @books，我发现 collection 中有 100 个 books。

(byebug) @books.count
  CACHE (0.0ms)  SELECT COUNT(*) FROM "books"
100

但是，进一步检查，它只是 collection 中前 10 本书的 10 份。 collection中只有id是1-10.

(byebug) @books.each { |b| puts b.id }
  Book Load (0.9ms)  SELECT  "books".* FROM "books" LIMIT  OFFSET   [["LIMIT", 10], ["OFFSET", 0]]
1
2
3
4
5
6
7
8
9
10

如果我转到下一页，我只会得到另外 100 个结果，但是 ids 只有 11-20:

(byebug) @books.count
   (0.4ms)  SELECT COUNT(*) FROM "books"
100
(byebug) @books.each { |b| puts b.id }
  Book Load (4.9ms)  SELECT  "books".* FROM "books" LIMIT  OFFSET   [["LIMIT", 10], ["OFFSET", 10]]
11
12
13
14
15
16
17
18
19
20

以下是我的观点：

<!-- index.html.erb -->
<h1>Books list:</h1>

<div>
  <table>
    <thead>
      <tr>
        <th>ID</th>
        <th>Title</th>
        <th>Author</th>
        <th>Genre</th>
        <th>Publication Date</th>
      </tr>
    </thead>
    <tbody id="book-list">
      <%= render @books %>
    </tbody>
  </table>
  </ul>
</div>

<div id="infinite-scrolling">
  <%= will_paginate %>
</div>

<!-- _book.html.erb -->
<% @books.each do |b| %>
<tr>
  <div>
    <td><%= b.id %></td>
    <td><%= b.title %></td>
    <td><%= b.author %></td>
    <td><%= b.genre %></td>
    <td><%= b.pub_date %></td>
  </div>
</tr>
<% end %>

Answer 1

我解决了我的问题。我处理的代码 <%= render @books %> 错误（我用得不多）。

我不得不更改部分代码以使其更加隐含。使用 @books.each do |b| 会使事情重复多次。将我的代码更改为：

<!-- _book.html.erb -->
<tr>
  <div>
    <td><%= book.id %></td>
    <td><%= book.title %></td>
    <td><%= book.author %></td>
    <td><%= book.genre %></td>
    <td><%= book.pub_date %></td>
  </div>
</tr>

解决了我所有的问题。

Rails 5：will_paginate gem 分页重复 objects（ID 1-10 等的 100 objects）。

Rails 5: will_paginate gem paginating repeated objects (100 objects of ids 1-10 etc).

ruby

ruby-on-rails

will-paginate

ruby-on-rails-5