A system has nested resources. For example
Farm HasMany Sectors
An example object relation will be like below
farm1 => [sector1]
farm2 => [sector2, sector3]
Now say, user1 has read,write permission on farm1.
user1 Has(read,write) on farm1
I need the system to automatically use the access for all the nested resources of farm1, in this case sector1.
In other words, something like user1.hasWritePermisson(sector1) should return true, though the ACL is actually stored with farm1. I need this even to work on the nested resources of sector and so on.
A straightforward solution would probably be to copy the access to all of the children objects of farm1 at the updating its acl. But I believe this would be a really inefficient one if farm1 contains thousands of sectors.
What would be the best way to achieve this in symfony2?
First of all. I think your question has nothing to do with SF2. In my opinion, you should create a efficient database which helps you to do the task. The rest is only a few queries away.
As I understand, it will be 3 major objects: User, Farm and Sector.
User could be in many Farms and Farms could be seen/wrote by many users
A Farm has many sectors, but a sector can only be in one farm
That being clarified, you will also need to declare the permissions for every user has in a farm. But, this will be declared in the many-to-many relationship with two relationship properties (read, write).
Once everything well designed, you should be able to create queries that satisfy your needs.
I know it's hard to understand because I'm talking in abstract, but let me know if you don't understand and I will draw you a scheme.