Re: My Favorite soapbox : XML linkage (was Re: [DotGNU]Jabber-thon)

[Barry Fitzgerald]

Gopal V wrote:
> 
> 
> *exactly* -- we're against "Vendor Lockin" and we attempt a similar
> coup ?. Execution via RPC is as similar to linking as IPC is to linking.
> Is IPC covered by GPL ?. Are pipes covered ? No !... So why should RPC
> be covered ?.
> 
> The question is "Is RPC mere aggregation or a specific interface based
> linking ...." ... I have no answer ?.
> 
> Is grep "^<.*>" | sed "s/^<\([^>]*\)>\(.*\)$/\1 said : \2/g" mere aggregation
> or linking ?... no one can deny they work together ;)
> 


It certainly is not a simple question.  Actually, I've been thinking
about this long and hard for the past couple of months...

My initial concern is that an already GPL'ed piece of Free Software
could have it's functions exposed to the outside world via a server. 
Well, that's not such a big deal until you put XML-RPC/SOAP into the mix
and the actual functions can be incorporated into another program.

And then, thinking about that, I came upon the realization that it would
be economically stupid to do such a thing (if you're a proprietary
company).

The reasoning: let's assume that all use of XML-RPC for "linking"
purposes is legally not linking, just to assume the "worst case
scenario" here.

You own XYZ proprietary company.  You really love ABC Free Software
product.  Do you: A. redistribute said Free Software product or B.
modify ABC Free Software products functions after converting it into a
linked library, exposing that functionality to an outside client.

Well, B. sounds nice if you want to legally violate the spirit of the
GNU GPL.  However, it's not without investment.

In order to get there, you'd have to produce the framework to expose
that functionality - and, even if that were trivial, the company would
still have to develop the proprietary interface to those XML-RPC calls
and thus interpret them.  That's a lot of work just to get around the
GNU GPL.

Now, let's assume that XML-RPC/SOAP didn't exist and I'm XYZ prop.
company trying to build a proprietary extension to a GNU GPL'ed
product.  I could, theoretically, do it with a wrapper.  That wrapper
could link the function and then output it's result to STDIO -- and
thus, give me access to the output of the function very similarly to the
way that XML-RPC does so.  The difference here is that that output by
that wrapper is not being served over a network and thus, the GNU GPL
applies.  But, that doesn't mean that it couldn't be served by - say, an
apache server... and thus we're back to the webservice issue without the
nice XML-RPC formatting.

So, it's not an easy issue to discuss.  But, I feel sorry for any
company that even tries to do this.  It really is cost prohibitive.

        -Barry