A Method Should Tell You What Changed

Thu, 01 Oct 2020 00:00:00 +0000

A balance reservation could be pending, captured, released, or expired. Only a pending reservation could move to one of the other three states.

That gave the system three commands:

capture reservation
release reservation
expire reservation

It did not get one method called updateReservation() with a status argument. The names said which transition the caller intended. The responses included the resulting status, so a caller did not have to guess what a successful request had produced.

An HTTP 200 Does Not Mean the Operation Succeeded

Mon, 01 Jan 2018 00:00:00 +0000

Two requests reach the same JSON application.

The first lacks authentication. The server returns HTTP 200 with this body:

{
 "status": 0,
 "error": {
 "code": 401,
 "message": "Unauthenticated"
 }
}

The second is authenticated but lacks permission to browse a collection. It also returns HTTP 200, this time with an empty array:

[]

Both behaviors are pinned by retained tests. Neither can be interpreted from the status code alone. Worse, the empty array is indistinguishable from an authorized search which genuinely found nothing.

Apis on Brian Faust

A Method Should Tell You What Changed

An HTTP 200 Does Not Mean the Operation Succeeded