REST APIs: custom HTTP headers vs URL parameters

Question

When do you use custom HTTP headers in the request part of a REST API ?

Example:

Would you ever use

GET /orders/view 
(custom HTTP header)          


        

Answer 1

There is no standard for REST however the accepted way would be

GET /orders/view/23

Not using the custom headers and hence the 23 after view assumes to be the id hence you would have a function that takes in the id and hence produces just that information.