Recap in HTTP design

Some of the common stuff when it comes to responding to REST based API are as follows :-

1. GET - 200 for OK, 404 when not found

2. POST - 201 for created and 204 No update. Returns 404 if it is a bad request. Returns 409 when conflict.

For long running or async processes, an API could just return 202 (ACCEPTED) with a link to poll status info. Agent can poll the status and once upon completed returns 303.
Results can be show here :-

HTTP/1.1 202 Accepted Location: /api/status/12345


HTTP/1.1 303 See Other Location: /api/orders/12345


3. PUT - 201 for created and 204 No update. Returns 409 when conflict.

4. PATCH - this is mainly used for update resource. It will return 415 for unsupported media, 400 bad request and 409 for conflict.

5. HEAD - for handling large content


If you have a long running task or wanted to poll status of a resources, then you can do something like this :-

POST to a resource and returns 202 (Accepted) with a location of resource URL. 

Issue GET on the new location resource 

Return 303 if creates a new resource and returns locations of the newly created resource url.