|--==> On Thu, 29 Jul 2010 10:45:58 +0200, "Charlie Clark"
CC> Am 29.07.2010, 10:25 Uhr, schrieb Free Ekanayaka
>>I agree that model objects and forms are not generally tight together,
>>even though I'd argue that virtually every web application will need
>>basic CRUD for the core entities.
CC> Form inference via schema adapter should be possible but I think there is
CC> consensus that interfaces that are schemas can cause more problems than
CC> they solve. Convenience versus overhead and confusion.
Agreed, I'm not thrilled by it either.
TH> I use a UML modeling tool to generate all my models and form
>>schemas so I
TH> tend not to write much code in these entities.
>>That's interesting, any pointer/link for this specific tool?
TH> I personally think the form schema is much more about the view than
>>Sure, however I believe the issue I was raising is orthogonal to this
>>one. Regardless how tight or loosely the form schema is bound to the
>>model, the authorization for a view in Repoze.bfg can effectively be
>>only True or False, which is simple and nice, but sometimes doesn't fit
>>what you need to do.
CC> In those cases you are free to add more to it such as, as Chris said,
CC> security proxies. Making this standard adds a lot of overhead to cases
CC> where it is totally irrelevant.
Absolutely. My question was more "is there another way I can think to
the problem, that plays well with plain Repoze.bfg (whose design I like
a lot, btw)?". I also appreciate the fact that, like Zope, Repoze.bfg is
pretty pluggable, so you can add what you need.
CC> NB. BFG's openness with regard to storage means you have to think about
CC> non-ZODB environments if you wish to have object-level security.
>>Let's make an example. You have a web application for sharing drawings,
>>you can upload drawings and for each drawing decide which other users
>>you want to share that drawing with. If you share a drawing with another
>>person, that other person can perform the same operations as you on it,
>>like tagging it or removing it.
>>Now let's say that you have views that act on collections of drawings,
>>like you could have a view for handling an HTTP request for tagging a
>>certain group of drawings or deleting them. The HTTP request for those
>>views would typically have a parameter holding a list for drawing IDs to
>>act on. How do you define the permission on those views? With a
>>model-based permissions system, you would simply make the view public
>>and let the model raise Unauthorized if you attempt to do something on a
>>drawing you don't have access too. However with a view-based permission
>>system you need to use some other pattern, and I'm not sure what would
CC> I would think you would need to add something to your application to
CC> handle this (something akin to workflow) but I don't see why you can't
CC> stick with security. BFG provides all the necessary hooks for
Introducing something like a workflow might be a good idea, I'll think
more about it, thanks.
CC> Regarding Maartijn's discussion of configuration close to the objects.
CC> Having grown up with Zope 2 I'm not keen to see declareProtected(), etc.
CC> return for this even if you have decorators. Much better, in my view, to
CC> have adapters and views implement behaviour and secure these.
CC> I guess the only thing that's missing is security aware form generation,
CC> ie. the ability to lock down parts of the form. With a form generation
CC> library such as deform this can be done at the view level, although it's
CC> not ideal.
Yeah, and you need security-awareness both ways, when you display the
form and when you process it.
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