Version 5 (modified by Dominic König, 14 years ago) ( diff )


Table of Contents

  1. General model
  2. Methods

BluePrint for Authorization (alternative version)

General model

Authorization is implemented for the following methods:

  • module access
  • controller access
  • table access (create/read/update/delete and custom method)
  • record access (create/read/update/delete and custom method)

Authorization policy is implemented as:

  • if a method is not restricted, then it is accessible for everyone
  • if a method is restricted, then access must be explicitly granted, otherwise its declined (Allow=>Deny order)

Permissions are assigned to roles (not to individual users):

  • roles are stored in auth_group
  • admin role is auth_group 1 (cannot be modified)
  • all methods on everything are allowed for members of the admin role
  • roles are assigned to users by auth_membership
    • this can happen either through admin UI or implicitly (no admin interaction)
    • it must be possible to log this
  • additional roles can be created after deployment
    • this will usually happen implicitly, i.e. not through admin UI
    • does not require a generic UI solution
  • roles of the actual user are re-read from the DB and stored in the session once per HTTP request
    • caching of this re-reading needs a proper method for cache invalidation on update notification
    • do not implement caching unless it really makes us performance problems

There are two pseudo-roles for record access:

  • author (=the author of the record)
  • editor (=the last author of the record)


Denial of access:

  • a method shn_unauthorized() realizes error notification and redirection as appropriate
  • non-interactive modes:
    • raise a HTTP error and a JSON error message
  • interactive modes, one of:
    • redirect (e.g. to login) and and display an error message on the target page (acceptable)
    • raise a HTTP error and display an error page, provide redirection options from the error page (more RESTful)
  • shn_unauthorized() takes an optional error message as argument

Module/Controller access:

  • access can be restricted inside the controllers using:
    • shn_has_role(role_name) which refers to the current user
  • shn_has_role() tests can be combined by and, or and not

Table/Record access:

  • table/record access can be restricted by:
    • shn_permit(table, method, role, id=None) adds role to the list of permitted roles for method on table/record
    • shn_deny(table, method, role, id=None) removes role from the list of permitted roles for method on table/record
    • shn_restrict(table, method, role, id=None) replaces the list of permitted roles for method on table/record with [role]
  • table/record access permission is tested by:
    • shn_permitted(table, method, id=None), which returns True/False refering to the current user
  • record restrictions override table permissions
  • table restrictions override record permissions
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