What is good way to limit the amount of comments shown to a user until they choose to view all?

问题

Currently I have an each loop in the template for where the comments are display. Say a user has 50 comments to a micropost they have posted. A long list showing 50 comments will be displayed.

To save space on the page I've decided I'd like to limit comments shown to 2-3 per micropost. If a user wishes to view more they can click "view more" or "view all". I'm wondering how a server would cope if there were like 10,000 comments and a user clicked "view all" which is why I may choose to implement "view more" then have like 50 more comments shown"

Anyway I'd like to know a good way to limit the amount of comments shown to a user until they choose to view all?

If I go the jquery/js route and make it so only the 2-3 most recent messages are shown the others would have still been loaded back end wouldn't they so wouldn't a better option be to control this in ruby on rails some how?

I'd really like some nice solutions/info on the best way to do this.

Any further info you need I'd be happy to provide.

Thanks Kind regards

回答1:

You can do like Facebook:

Show only 2/3 comments. Load only 2/3 comments from the backend.
When the users clicks "Show more", it shows 50 more. It loads them through AJAX. So on the backend you only get a request like "GET 50 comments EXCEPT the three firsts".
Another "Show more" link is shown. It will load 50 other comments except the 53 firsts.

On Facebook, you can't load more than 50 comments at once. I think you should do the same.

回答2:

The clean way is to implement pagination for comments.

回答3:

I suppose there's a simple belongs_to and has_many relationship between Post and Comment. I normally will do:

routes:

resources :posts do
  resources :comments
end

model: set a default page size:

class Comments < ActiveRecord::Base
  belongs_to :post

  DEFAULT_PAGE_SIZE = 25
end

controller:

class CommentsController
  def index
    post = Post.find(params[:post_id])
    offset = params[:offset] || 0
    limit = params[:limit] || Comment::DEFAULT_PAGE_SIZE
    @comments = post.comments.offset(offset).limit(limit)

    respond_to do |format|
      #respond as you like
    end
  end

  # more actions...
end

view, a load more link something like, to load the comments via ajax:

<%= link_to "load more comments", post_comments_path(@post, :format => 'js'), :method => :get, :remote=>true id='load-more-comments' %>

and you also would like to bind the offset to the ajax post:

$ ->
  $('#load-more-comments').on 'ajax:before', (event) ->
    el = $(this)
    offset = #count your offset, I often do by counting the <li>s already in the <ul>
    el.data 'params', "offset=#{offset}"
    # you could also pass the limit: el.data 'params', "offset=#{offset}&limit=#{some limit}"
  .on 'ajax:complete', (event, xhr, status) ->
    el = $(this)
    el.removeData 'params' # remember to remove this.

I am also interested in what's the better way to do this. Looking forward to the answers and critics. :)

来源：https://stackoverflow.com/questions/10174127/what-is-good-way-to-limit-the-amount-of-comments-shown-to-a-user-until-they-choo

标签

javascript

jquery

ruby-on-rails

ruby-on-rails-3

ruby-on-rails-3.1