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Issue 21: HTTP binding does not support out first MEPs

From: Hugo Haas <hugo@w3.org>
Date: Thu, 9 Dec 2004 16:24:56 -0800
To: www-ws-desc@w3.org
Message-ID: <20041210002456.GA2846@w3.org>
Hi.

I am afraid that I am going to reopen an issue (issue 21[1]), but this
is with additional information as I was implementing the resolution in
Part 3.

We took the decision that the HTTP binding supports out-message first
MEPs, saying that the service could initiate the HTTP request, if it
knew where to do so somehow.

Some people at the last F2F pointed out that this "somehow" was an
interoperability issue.

Actually, I think that it is not "somehow" that this is communicated.
The spec clearly says that the HTTP Request URI is built from
@location on a binding operation and @address on an endpoint URI.

What that means is that the Request URI that a service would use for
this request is well-known and communicated in a standard way: in the
WSDL document itself. A (pseudo) example:

  <description>

    <interface>
      <operation pattern="out-in">
	<output/>
	<input/>
      </operation>
    </interface>

    <binding type="HTTP">
      <operation location="http://myclient.example/"/>
    </binding>

    <service>
      <endpoint address="http://myservice.example/"/>
    </service>

  </description>

Here, the service does an HTTP request to http://myclient.example/ and
gets a reply from the client.

The downside is that it is completely static.

I have mixed feelings about the usefulness of this, and this changes
the text that we agreed to put in the spec, so I think that the WG
should consider this (forced) change of plan.

Cheers,

Hugo

  1. http://www.w3.org/2002/ws/desc/4/lc-issues/issues.html#LC21
-- 
Hugo Haas - W3C
mailto:hugo@w3.org - http://www.w3.org/People/Hugo/

Received on Friday, 10 December 2004 00:24:57 GMT

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