Re: the meaning of stateless

Hi Mike,

On Wed, Apr 24, 2013 at 5:25 PM, Mike Schinkel <[email protected]> wrote:
> Hi Mark,
>
> I'm really struggling to get the nuances with this, hoping you can help.
>
> On Apr 24, 2013, at 2:23 PM, Mark Baker <[email protected]> wrote:
>
> It is, but the *meaning* of future messages doesn't change if the
> state of that resource changes.
>
>
> If that is absolutely true, then how can REST implement workflow or
> transactions? For example (admittedly trivial, but the pattern could be
> applied to something much less than trivial):
>
> GET /client/abc123/accounts
> ---> 200 ok, [ { "account": "checking", "balance": 500.00 },{ "account":
> "savings", "balance": 100.00 }]
>
> POST /client/abc123/account-transfer/new
> ---> 200 ok, Location: /account-transfer/12345
>
> PUT /client/abc123/account-transfer/12345/checking
> balance=350
> ---> 200 ok
>
> PUT /client/abc123/account-transfer/12345/savings
> balance=250
> ---> 200 ok
>
> POST /client/abc123/account-transfer/12345
> action=commit
> ---> 200 ok
>
>
> In the real world I can come up with all kind of other examples where an
> action based on a POST would be different based on POSTs and PUTs that came
> before it, or the thing that needs to be accomplished cannot be. So my
> intuition tells me that there must be some kind of state that is okay and
> some kind of state that is bad but the more questions I ask the less I'm
> confident that I understand the answer. Based on your comment I would be
> driven to think that systems cannot implement workflow or transactions and
> still be RESTful.

Well, it sounds like you have a far narrower view than I do of what
constitutes "workflow" or "transactions", but yah, what you've got
above is totally stateful.

Mark.