如何在Rails 4中缓存个性化片段？

Question

我的应用程序(Rails 4)允许用户对帖子进行投票.是否可以缓存帖子,但个性化投票缓存,以便显示一个针对current_user的个性化？例如,用户是否投票.

我宁愿不改变html结构来实现这一点.

# posts/_post.html.slim
- cache post do
  h1 = post.title
  = post.text
  = render 'votes/form', post: post

# votes/_form.html.slim
- if signed_in? && current_user.voted?(post)
  = form_for current_user.votes.find_by(post: post), method: :delete do |f|
    = f.submit
- else
  = form_for Vote.new do |f|
    = f.submit

Answer 1

你有两个选择:

选项1:不要缓存投票

这是最简单的解决方案,也是我个人推荐的解决方案.您只是不缓存动态用户相关部分,因此您有这样的事情:

# posts/_post.html.slim
- cache post do
  h1 = post.title
  = post.text
= render 'votes/form', post: post # not cached

选项2:使用javascript

这个解决方案更复杂,但实际上是basecamp如何做到这一点(但主要是用更简单的例子).您在页面上呈现了两个部分,但使用javascript删除其中一个部分.以下是使用jQuery和CoffeeScript的示例:

# posts/_post.html.slim
- cache post do
  h1 = post.title
  = post.text
  = render 'votes/form', post: post

# votes/_form.html.slim
div#votes{"data-id" => post.id}
  .not_voted
    = form_for current_user.votes.find_by(post: post), method: :delete do |f|
      = f.submit
  .voted
    = form_for Vote.new do |f|
      = f.submit

# css
.not_voted {
  display:none;
}

# javascript (coffeescript)
jQuery ->
  if $('#votes').length
    $.getScript('/posts/current/' + $('#votes').data('id'))

# posts_controller.b
def current
  @post = Post.find(params[:id])
end

# users/current.js.erb
<% signed_in? && current_user.voted?(@post) %>
  $('.voted').hide();
  $('.not_voted').show();
<% end %>

但是我会正确地更改voted?方法以接受id,因此您不需要进行新查询.您可以在此railscast中了解有关此方法的更多信息:http: //railscasts.com/episodes/169-dynamic-page-caching-revised?view=asciicast