= !BluePrint for Authorization =
== User Stories ==
 * A Developer needs to be able to restrict access to a Module
  * done: s3.modules (Add Controller check as well as menu check. Configure permissions in 000_config.py?)
 * A Developer needs to be able to restrict access to a Function
  * Decorator function - although it doesn't support OR (we could easily write our own function to do this, though)
 * A Developer needs to be able to restrict access to a resource
  * REST controller can be blocked via a Decorator
  * Full security policy can be invoked, but this is painful/untested within S3 recently
  * We could check for what other functions can access data? Sync. Hard to maintain though.
  * Need a new method. Do all accesses go via S3XRC? If not, then needs to be a DAL-level method! Use the Web2Py 'full' for tables but not records?
 * A Developer needs to be able to restrict access to a record
  * Add 2 reusable multiple=True fields to each table which needs this: {{{reader_id}}} & {{{writer_id}}} combined as {{{permissions_id}}}
   * Full backward compatibility since they default to None
  * reader_id check as a new API function
   * combine with the deleted==True check?
    * makes it easier to then replace that check with an 'inactive' field which is a date instead of a boolean, so that records can be set to expire (as well as giving us easy access to know when a record was deleted)
   * Option 1: Do the check alongside deleted as part of a big JOIN
{{{
def shn_accessible_query(user, table):
    """ Modified version of current function from models/01_crud.py """

    deleted = (table.deleted == None)

    _memberships = db.auth_membership
    memberships = db(_memberships.user_id == user).select(_memberships.group_id)
    roles = []
    for membership in memberships:
        roles.append(membership.group_id)

    if 1 in roles:
        # Admins see all data
        query = deleted
    else:
       # Fields with no restriction
       accessible = (table.reader_id == None)
       for role in roles:
           accessible = accessible & (table.reader_id == role) 
       query = deleted & accessible
    return query

def user_function:
    table = db[tablename]
    available = shn_accessible_query(user, table)
    query = available & query
}}}
    * Advantages:
     * Combines the deleted into single API call
     * Single JOIN for optimal DB performance
    * Disadvantage:
     * Can we deal with Multiple=True?
   * Option 2: Do the check in Python after the initial query has returned
    * Advantage: Allows us to process the Multiple=True field properly
    * Disadvantage: More records pulled from DB than necessary
  * writer_id check: All Write access goes via S3XRC so can be checked there (we can also develop an API call for Manual DAL access?)
  * UI to manage the fields.
   * We expect relatively few groups per instance, so can use the checkboxes widget?
   * Have a single checkbox for 'Restrict access' which then opens out the 2 fields.
 * A Person's Subscriptions shouldn't be visible by default.
  * Admin or themselves is OK
   * This requires the default of adding 1 group per user!?
 * A Person's Contacts shouldn't be visible by default.
  * Authenticated is OK
   * This requires all authenticated users to be added to the 'Authenticated' group
 * An Admin should be able to restrict access to records to just those within a certain GIS location (e.g. Country or Region)
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BluePrintAuthenticationAccess

BluePrints