RE: EDI over http?

[Andras Salamon <andras@xxxxxxxx>]

On Fri, 27 Jun 1997, Erron Criddle wrote:
> At 08:03 PM 6/24/97 -0500, Rik Drummond <drummond@xxxxxxxxxx> wrote:
> >Should we focus on Http or stmp (as discussed below) for doing real time EDI?
> >What do others think?
> 
> My suggestion is to go HTTP Rik...SMTP is too inflexible.

Basic SMTP is very inflexible, which is why the ESMTP framework was
introduced to allow protocol extensions.  ESMTP is at least as flexible
as the HTTP protocol extension mechanisms.

Basic SMTP does not have sufficiently powerful mechanisms for a two-way
information flow.  The server-side responses are essentially three-digit
numeric codes, so it becomes necessary to either send server-generated
information in the text comments (for instance message identifiers or
transport acknowledgements), which is nonstandard, or a separate return
SMTP message needs to be used, which increases the nondeterminacy and
ordering problems.

In my view, the main gain in HTTP over basic SMTP is richer information
in the server-side responses.

None of this precludes defining an ESMTP extension to enable specific
types of server-side responses in a standard way.  Defining and
implementing what information needs to be passed back to the client
_during_ the message transfer, is difficult but it is essentially the
same whether HTTP or ESMTP is used.

I feel that the functional differences between ESMTP and HTTP in this
context are small enough that the focus at this stage should be on the
transport model and the information passing between server and client,
not on the actual implementation of the transport model.  Once there is
some consensus on the model, it becomes possible to translate it into
ESMTP or HTTP or Internet-EDI-Protocol or whatever.

Other than server-side responses, are there any other problems with
(E)SMTP as a protocol?

-- Andras Salamon                              andras@xxxxxxxx