How does Nginx map to different backend servers based on message headers or message content?

Question

For example, when the accessing user is a mobile phone user or a PC user, the packets sent are inconsistent. How to map to different back-end servers based on different flags in the packets?
Are there any third-party modules?
Can we rely on nginx native modules to achieve this function?

Answer 1

Use ifcommand

Answer 2

nginx configuration location summary and how to write rewrite rules