Forum OpenACS Q&A: What (really) is subsite-awareness?

I've been searching around a bit in forums and bugs trying to understand the elusive subsite-awareness. I found several places where packages claim to have this property.

For example, the "Directory" package claims awareness and, the best I can tell with a quick scan, in this context it really means that the package plays nicely with the groups (actually application groups) system. Aother example would be "Photo Album" (Jeff's version) where awareness means allowing access only to content associated with a particular subsite.

So, I'm thinking that subsite-awareness is:

a) being aware of and using subsite application groups and the permissions applied to objects through association with these groups, and

b) associating each object with the package_id of a particular subsite so that "select"s return the subset of objects having this association. I found context_id and said "woohoo, can I just set and select objects based on this value?", and then I read Dave's comments that say "don't do that!", so I'm not sure how to go about this aspect of awareness.

I would like to understand the components, tools, and procedures required to make an application subsite-aware. Would anyone care to break this down into a step-by-step process or set of guidleines so that I and others can understand and apply the principles in order to make our applications play nicely now and in the future? If not, I'll still read any comments that anyone would like to add.

Randy

Thank you, Dave. That was very helpful and I was able to incorporate the package_id column so that now only data created under an instance is visible to that instance.

Maybe this should be added to Joel's newpackage tutorial. I did use his tutorial as a basis to begin building my package.

Now, I would like to address the permissions aspect. As it stands now, there is a single explicit 'admin' right granted to the object's creator in the __new pgsql procedure. What I would like to do is expand on this by creating groups associated with a package instance, and use those groups to grant general rights such as read, modify, create, delete, and possibly change-ownership. I would like to learn how to this programatically.

Can anyone briefly describe the steps necessary to add this functionality?

Again, thanks Dave for your time and trouble.

Can you think of a good example package(s) that might illustrate the callbacks and api(s) mentioned above?