ZEO Client space was: [Zope] Prerequisites for a desktop IDE, or any desktop app w/Zope

[Michel Pelletier]

On Thu, 24 May 2001, Tim Cook wrote:

> Michel Pelletier wrote:
>
> > XMLRPC could do this, but I'm afraid it would be seriously
> > limited.  XMLRPC is very useful, but it does not map as well as it could
> > onto the python object model.  I would prefer to see a GUI client running
> > in the same process space as a ZEO client, this way the GUI client could
> > do everything that Zope could do and re-use alot of the existing
> > interfaces (like security, acquisition, script objects, etc).
> >
>
> Michel,
> I took this off list because it was off topic for the thread. But
> feel free to Cc it back if you feel it's important.  I think it
> was covered a few weeks ago on the -dev list but couldn't locate
> it.

It's not off topic so I'm cc:ing the list.

> Anyway, the question is: I thought I had read that using ZEO
> basically by-passed the Zope security model? Maybe I was thinking
> of direct ZODB access?

This is a good question.

Using ZEO does bypass the Zope security model, but then again, Zope
bypasses the Zope security model.  Zope is, essentially, a client that
implements an application on top of a persistent database.  Why can't your
client do the same thing?  Zope enforces security upon its users using
tested, re-usable interfaces.

You're should essentially change the user interface to the Zope core code
by making it call wxPython widgets or whatever instead of spewing HTML to
a browser over a socket.  If this GUIfied ZEO client ran on the same
machine as the server, it would actually be safer than a "real" Zope
ZEO client, which is exposed to the web.

We use ZEO clients to access Zope through many different interfaces, not
necessarily all of them over a network, or running in a context we don't
trust.  We use ZEO clients to debug zope from the command line, to serve
just FTP or a monitor server, and each different way of doingit is just a
shim on top of the core Zope interfaces.

By going with xml-rpc, you'll be shoving *very* rich interface semantics
of a full blown windowing sytem down the tiny semantic straw of xml-rpc,
to try and manipulate interfaces that were originally indented to be used
by medium to poor semantic HTML interfaces.  If you use a ZEO client,
there are no bottle necks.  You could render the object system in 3D
OpenGL if you wanted to, and still enforce the user.

Jerome's ZShell script shows how this can be done safely.  His shell is
essentialy just another interface to the Zope core code.  It would be very
dangerous if it did not use Zope's security API to restrict its actions.

In zshell's case, the interface is really simple, a command line. It is
probably not as safe to to grant access to this command line over
unprotected networks. and it would be unsafe to expose a GUIfied ZEO
client to unprotected networks, but this is easily mitigatable with things
like ssh or ssl.

-Michel