Re: Web service question... -- RPG400-L

All,

FWIW, without wanting to disagree about what REST is (or isn't), much
discussion of REST on the web points to its relative simplicity and
implementation. Many of these examples show how a possibly complex procedure
call can be simplified to a simple URL.

I suspect that in many cases, this is what people 'mean' when they talk
about a RESTful implementation or interface - the fact that you can model
your application (a collection of web services) in such a way that each is a
stand-alone object which can be called using only a URL to perform a
specific action. This 2003 article points out that 85% of developers who
interface to Amazon's web services do so using REST rather than SOAP. Old
article, of course, but stil...

This is not to say that this is what REST *is* - but I have to admit that
when I first looked it up on Wikipedia several years ago, I was pretty
baffled. On looking at that Wikipedia entry again, I think the total lack of
good examples is a severe deficiency.

Rory

p.s. KrengelTech (home of Aaron Bartell) has a pretty nifty product called
DB2WSE (http://iwiki.krengeltech.com/wiki/DB2WSE_User_Guide) which allows
you to run SQL queries against your back-end database using either a
'complex' XML interface or a much simpler REST (or at least REST-like)
interface, e.g.:

http://red.rpg-xml.com/db2wse/demo:demo/petstore/item/est-1

instead of

<DB2WSEREQ>
<STATEMENT>
select * from petstore/item where itemid = 'EST-1'
</STATEMENT>
<USER>DEMO</USER>
<PASSWORD>DEMO</PASSWORD></DB2WSEREQ>

It is this user-visible feature of REST (the simple interface) which is what
many people 'mean' when they talk about the benefits of REST.

On Wed, Jul 20, 2011 at 9:25 AM, Henrik Rützou <hr@xxxxxxxxxxxx> wrote:

I agree with that, REST has a very loose definition and I will go further
than
that and argue that most REST services when evoked from AJAX in a browser
uses POST in order to ensure that the client don't get buffered data.

You can argue that REST acts like and is a RPC (Remote Procedure Call)

As an example a CGI program that acts as a CRUD service and where the
program just remains active and stateless under the Apache environment.

Further more XML isn't the only way to communicate because the interface
is bilatteral agreed so a REST service could also communicate in JSON,
consume FORMDATA etc.

Most of these definitions discussed here overlaps each other in one or
several ways.

On Wed, Jul 20, 2011 at 5:48 PM, Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx

wrote:

That's a reasonable description, but of course the devil is in the
details. First, a lot of RESTful services don't rely on the HTTP verb.
They all use GET (some use POST) and then leave it up to the service to
determine what to do. This is often the case when you simply expose
business logic as RESTful services; the HTTP interface is always the
same, the service interprets and executes the request. That makes it a
little easier to program the JavaScript on the browser; it doesn't have
to worry about different verbs. Second, XML is no longer the only or in
some cases even the dominant format for the message. JSON is used more
and more for both sides of the transaction, especially in Rich UI
applications where both the client and server are written by the same
development organization.

Joe

The way I've always described it...

1) In REST, the URI describes a "thing" to be acted upon. (Ex: An
invoice, PO, zip code, whatever)

2) In REST, the HTTP method is the "verb" telling it what to do.
(Retrieve, Update, Delete, Insert, etc)

3) In SOAP, the URI describes an 'endpoint' which generally refers to
some piece of software rather than a thing to act upon. A second URI,
called Soap Action describes what that software should do. A set of
input parameters defined in an XML message describe what data to act

upon.

4) In both cases, an XML message is returned, either as the output of
the web service, or describing the effect of calling the web service.

On 7/20/2011 4:51 AM, Larry Ducie wrote:

REST is a concept - it is the idea that the client has a picture (or
representation) of a "thing" in a certain well defined and valid
"state". The "thing" exists on the remote server. Changes to the
state of the "thing" from one valid state to another valid state is
performed via a call to a web service. A RESTful architecture will
provide a set of services that allow the client to describe the
current state (customer details, order details, invoice details) and
to also change the current state (start order, add item, pay bill).

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Regards,
Henrik Rützou

http://powerEXT.com <http://powerext.com/>
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