Consequences of POST not being idempotent (RESTful API)

Question

I am wondering if my current approach makes sense or if there is a better way to do it.

I have multiple situations where i want to create new objects and let the server

Answer 1

No matter what HTTP method you use, it is theoretically impossible to make an idempotent request without generating the unique identifier client-side, temporarily (as part of some request checking system) or as the permanent server id. An HTTP request being lost will not create a duplicate, though there is a concern that the request could succeed getting to the server but the response does not make it back to the client.

If the end client can easily delete duplicates and they don't cause inherent data conflicts it is probably not a big enough deal to develop an ad-hoc duplication prevention system. Use POST for the request and send the client back a 201 status in the HTTP header and the server-generated unique id in the body of the response. If you have data that shows duplications are a frequent occurrence or any duplicate causes significant problems, I would use PUT and create the unique id client-side. Use the client created id as the database id - there is no advantage to creating an additional unique id on the server.