Re: SMTP Use Cases

On Fri, 22 Oct 2004, Markus Hofmann wrote:

> Hilarie Orman wrote:
>
> > There's an odd recursive aspect to applying OPES to SMTP, and I think
> > it is important to clarify why SMTP will benefit from OPES, 
> As I mentioned before - with OPES you can send parts of an applications 
> message to the callout server, you're not forced to send the entire message. 
> With SMTP, you would always have to sens the entire message. LEss efficient. 
> Do I miss anything here?
With SMTP, the adaptation box must know and speak SMTP. With OPES, the 
adaptation box must know and speak some OCP profile. OCP is designed 
for adaptations. SMTP is not. And the adaptation box does not have to 
learn new protocols to adapt messages they carry. One would not have 
to build a FooBar adaptation box to adapt FooBar protocol; with some 
lack, the old adaptation box can be used as-is.
Partial message adaptation is a side-effect. You are simply talking 
about an OCP profile that defines "content" in such a way that partial 
SMTP adaptation becomes possible. With some luck, partial HTTP 
adaptation may be possible with the same or very similar profile.
OPES makes some sense when we look at one application protocol in 
isolation (e.g., HTTP or SMTP). That's why ICAP is still alive. 
However, OPES true power is adaptation of multiple application 
protocols with little extra effort. That is, it scales with the number 
of application protocols. That scale is what current ICAP vendors 
struggle with.
Alex.