[Zope3-dev] Zope 3 without ZODB

[Jim Fulton]

On Jan 20, 2007, at 3:07 PM, Chris Withers wrote:

> Jim Fulton wrote:
>>> ...mean that Zope 3 is currently hard-coded to need a ZODB?
>> That depends on what you mean by Zope 3.  If you define "Zope 3"  
>> as  zope.app.server.main, or zope.app.twisted.main, then yes, it  
>> is. I wouldn't define it that way, although I can see how others  
>> might. :)
>
> Well, for me, a Zope 3 instance is what you get when you run  
> mkzopeinstance. If there's other alternatives to that, I'd be  
> interested in exploring them :-)

I think mkzopeinstance if fine, as far as it goes.  I don't plan to  
use it in the future, even for setting up the existing main programs,  
which generally do meet my needs. (I have no interest in running Zope  
w/o ZODB myself.)

>>> If so, how should we go about making this optional?
>> You would need to write a different main program that did  
>> something else.
>
> Has anyone else attempted this?

As I have said over and over. Yes.


> Does grok have one of these?

I suspect so,.

>
>> You would need to understand how the publisher framework worked  
>> and plug in an alternate publication that traversed to non-ZODB  
>> objects.
>
> I touched on this with my reply to Philip, but surely the  
> publication type should just be operating on objects that implement  
> an interface?
> It seems odd, at least to me, that I'd need to rewrite publications  
> that know about things like http, ftp and webdav just because the  
> object I want to publish come from a file system or relational  
> database rather than a zodb...

The publisher knows nothing about the application. The publication  
object is the object responsible for providing this integration. It  
is not a very complicated interface to implement.  Depending on your  
needs, you can likely subclass the existing piblication if you wish.

...

>>> (I am willing to put the work in to make this happen if people  
>>> give me some hints...)
>> Other people have already made this happen. I don't know if any of  
>> their code is public or if they have written up what they've done.
>
> This is a bit cryptic... are you saying there is an "alternative  
> zope 3" that already has alternatives to zope.app.server.main or  
> zope.app.twisted.main? If so, where are they to be found?

Alan Runyan and Sidnei Da Silva created one of the earliest Zope 3  
applications using SQL Objects.  I don't remember the name of their  
application or what it's status is.  Maybe they'll chime in or you  
can ask them.  Launchpad is a Zope 3 application that doesn't use  
ZODB.  I don't think that code is available.

I'll note, and this will be, hopefully, the last comment on this  
thread, that a Zope 3 application based on relational databases is  
likely to look a lot different than a traditional Zope application.  
In particular, I wouldn't expect such an application to use an object  
filing system model, which is difficult to achieve with an RDBMS.  I  
expect that such an application would simply expose pages in some URL  
space that isn't derived from data structures and that these pages  
would simply call into databases as necessary.  I expect that such an  
application would look a lot like applications built with other web  
frameworks.

Jim

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