Django处理分页以实现动态顺序

Question

I have done to query content and give as next_url, previous_url , etc. Problem is that query is based on dynamic sorting (just like Facebook newsfeed).

How can I handle for following scenario ?

User request page 1 and see article 10242. User haven't request page 2 yet. Due to sorting algorithm, article 10242 will potentially moved to page 2. If so, when user request page 2, user will see duplicate post.

I can't simply delete duplicate post on app. It will be okay for duplicate issue but let say when user request page 1, article 10333 is in page 2 but when user request page 2, article 10333 moves to page 1. Is there any recommended mechanism for pagination to support dynamic sorting?

Answer 1

Few suggestions:

1. Change the algorithm to hold a dirty parameter. Anytime someone likes it or changes are made, it becomes dirty and the sorting algorithm can be changed to factor it in. I used couple of search db's (elasticsearch and algolia) that allowed me to customize sorting order based on various parameters. Alongwith this change, you need a user state of what has been viewed and what can be viewed and use it as a filter.
   Here is a nice paper where facebook discusses some of its approaches.

2. A simpler approach would be to hold the information of what has been viewed by a user and when the user tries to fetch information filter/demote the article. Keeping per user state will take care of the issue where an article might be viewed by one person but not by another.
   I personally like nosql databases or something like redis/memcached for such state information