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RE: Article: Fat protocols slow Web services

From: Anne Thomas Manes <anne@manes.net>
Date: Wed, 9 Jan 2002 10:06:32 -0800
To: "Roger L. Costello" <costello@mitre.org>, "Xml-Dist-App@W3. Org" <xml-dist-app@w3.org>
I take a different viewpoint. I don't like to make generalizations along the
line of "the proper use of SOAP is to send asynchronous, connectionless
messages". While I agree that many Web services should be designed using an
asynchronous, connectionless architecture, I believe that SOAP can and
should be used however people decide to use it. SOAP is simply a messaging
envelope. SOAP messages can be sent over a variety of protocols. They can be
sent and consumed by pretty much any type of application.

Making mandates about the proper use of a technology will generally get
ignored by the general public. I remember similar arguments about BTRIEVE.
People will use technology wherever that technology can help them solve the
problem at hand.

Which brings me back to the point I wanted to make: The application
architecture that you choose to use should be determined by the requirements
of your application. Some applications lend themselves most easily to a
request/response architecture, while others favor an asynchronous model.
Sometimes you can build your application with either architecture.
Sometimes, though, you really need to use one and not the other. (I'm not
going to use asynchronous messaging -- regardless of it's reliability -- if
I'm transferring funds from one account to another.) What's interesting
about SOAP is that it easily supports both models.

As I see it, the biggest challenge is that a huge majority of developers
have never developed an asynchronous application. Lot's of people who are
playing with SOAP and .NET these days are using request/response because
it's what's familiar (or it's the only way they know). Meanwhile, all the
tools out there are designed to serve this majority, so the tools promote
the use of request/response also.

Meanwhile, I view the whole premise of this article (the bloated nature of
XML) to be completely specious. If we can realistically think about using
the Internet to deliver video on demand, then it's ridiculous to talk about
the inefficiency of using XML versus a binary encoding system.


> -----Original Message-----
> From: xml-dist-app-request@w3.org [mailto:xml-dist-app-request@w3.org]On
> Behalf Of Roger L. Costello
> Sent: Wednesday, January 09, 2002 5:46 AM
> To: xml-dist-app@w3.org
> Subject: Re: Article: Fat protocols slow Web services
> Great discussion!  Let me see if I understand Kurt what you are saying
> is the proper use of Web services.  You are saying that the proper use
> of SOAP is to send asynchronous, connectionless messages ... similar to
> how we use the postal service.  To take the postal service analogy, we
> send a letter (message).  At some point the letter arrives at the
> destination.  [To some extent we have control over how fast the letter
> arrives - one day express, priority, first class, or regular.]  The
> receiver of the letter processes it when he/she has the time.  Perhaps
> the receiver may even reply.  Thus, the letter (message) has been sent
> in an asynchronous, connectionless fashion.  Is this analogous to the
> kind of use that you see for SOAP?  Thus, a SOAP message is sent, and at
> some point the message arrives at the destination.  The receiver of the
> message will process it when it has time, and then may reply with a
> message. The point is that the sender is not halted processing, awaiting
> a response.
> Thus, the wrong use of SOAP is to expect an instantaneous/real-time
> reponse to a message.
> Is this a fair summary?
> You made an interesting statement:
> > Asynchronous, message oriented applications have a different design
> > and architecture from stateful, RPC oriented apps. They change the way
> > that coding is done, they change the way that applications are built,
> > and they even alter the expectations of the user base.
> Interesting!  Can you elaborate upon the design and architecture of
> asynchronous, message-oriented applications, and upon the expectations
> of the users of such applications?
> /Roger
> Kurt Cagle wrote:
> >
> > Joshua,
> >
> > I don't disagree with your contention. RPCs over WANs in general are bad
> > ideas, regardless of whether you're talking about XML, DCOM,
> RMI or Joe's
> > handy brokering service, and over connectionless, asynchronous protocols
> > like HTTP they are even worse. My contention here is that the
> industry is
> > moving to an RPC model, though, with the emphasis on
> technologies like .NET,
> > and it's this that gets my eye to twitching. You CAN do .NET
> calls that are
> > message oriented and asynchronous - but that's not what most people are
> > hearing; I've heard any number of people saying that they didn't even
> > realize you could do asynchronous .NET calls.
> >
> > Asynchronous, message oriented applications have a different design and
> > architecture from stateful, RPC oriented apps. They change the way that
> > coding is done, they change the way that applications are
> built, and they
> > even alter the expectations of the user base. I think .NET is cool
> > technology, but I worry that people out there are going to use VB design
> > principles to build applications that will have a major
> negative impact on
> > the web itself. If its just a matter of education, that's
> great, but I don't
> > want to see the Internet slow to a crawl as 85% of the
> developer base learns
> > how to build asynchronous messaging applications.
> >
> > -- Kurt Cagle
> >
> > ----- Original Message -----
> > From: "Joshua Allen" <joshuaa@microsoft.com>
> > To: "Kurt Cagle" <kurt@kurtcagle.net>; "Roger L. Costello"
> > <costello@mitre.org>; <xml-dist-app@w3.org>
> > Sent: Tuesday, January 08, 2002 3:56 PM
> > Subject: RE: Article: Fat protocols slow Web services
> >
> > > The most recent rise of XML-based RPC web services is worrisome then
> > from
> > > a number of standpoints. SOAP messages ARE big. The current efforts by
> > a
> > > number of vendors are typically expanding the relevant bytes being
> > sent by
> > > a  factor of ten, you're adding the overhead of security and type
> > > encoding/decoding, and they are making this technology transparent -
> > drag
> > > and drop the requisite Bean or COM control on your form, and you can
> > start
> > > writing synchronous RPCs without even knowing that you're doing it.
> > This
> > > means that there will be a lot of very badly written web services
> > that, by
> > > themselves, work fine, but overall contribute to the degradation of
> > the
> > > networks.
> >
> > Take "XML" out of this, and everything you say is still true.
> > Synchronous RPC over a WAN is rough, no matter how it is encoded.  I
> > don't see any evidence at all that the RPC people wrap with XML is worse
> > than the crazy things people do with RMI and DCOM.
> >
> > All of the issues you mention are important for *any* synchronous RPC
> > system.  Encoding is one of the least important issues in most cases, so
> > if you are implying that finding a less "fat" encoding will solve the
> > problems you mention, you are misleading people.
Received on Wednesday, 9 January 2002 10:02:40 UTC

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