Authorize::Rule - Rule-based authorization mechanism
version 0.003
This is an extensive example, showing various options:
my $auth = Authorize::Rule->new( rules => { dev => { Payroll => [ [0] ], # always deny '' => [ [1] ], # default allow for unknown resources }, tester => { '' => [ # labeled rulesets 'check tester' => [ # all rules must apply # key 'is_test' with value 1 # and keys test_name/test_id must exist 1, { is_test => 1 }, 'test_name', 'test_id' ], 'default' => [0], ] }, admin => { '' => [ [1] ] }, biz_rel => { Graphs => [ [0] ], Databases => [ # access to reservations table [ 1, { table => 'Reservations' } ], ], Invoices => [ [ 0, 'user' ], [ 1 ], ], Payroll => [ [1] ], Revenue => [ [1] ], '' => [ [0] ], }, support => { Databases => [ [ 1, { table => 'Complaints' } ], ], Invoices => [ [1] ], '' => [ [0] ], }, sysadmins => { Graphs => [ [1] ], '' => [ [0] ], }, }, );
(this example is not taken from any actual code)
Authorize::Rule allows you to provide a set of rulesets, each containing rules, for authorizing access of entities to resources. This does not cover authentication, or fine-grained parameter checking.
While authentication asks "who are you?", authorization asks "what are you allowed to do?"
The system is based on decisions per entities, resources, and any optional parameters.
I can't promise some of this won't change in the next few versions.
Stay tuned.
The specification covers several elements:
Entity
Resource
Action
Optional parameters
Optional label
The general structure is:
{ ENTITY => { RESOURCE => [ OPTIONAL_LABEL => [ ACTION, RULE1, RULE2, ...RULE10 ], ] } }
Allowed rules are:
# parameters must have this key with this value [ $action, { key => 'value' } ] [ $action, { name => 'Marge' } ] [ $action, { names => [ qw<Marge Homer Lisa Bart Maggie> ] } ] [ $action, { families => { Simpsons => [...] } } ] # parameters must have these keys, values aren't checked [ $action, 'key1', 'key2', ... ] # they can be seamlessly mixed [ $action, { Company => 'Samsung' }, { Product => 'Phone' }, 'model_id' ] # and yes, this is the equivalent of: [ $action, { Company => 'Samsung', Product => 'Phone' }, 'model_id' ] # labels can be applied to rulesets: 'verifying test account' => [ $action, { username => 'tester' } ]
An action is either true or false, but can be provided any defined value. Traditionally these will be 1 or 0:
1
0
[ 1, RULES... ] [ 0, RULES... ] [ 'FAILURE', RULES... ] my $result = $auth->is_allowed( $entity, $resource ); if ( $result eq 'FAILURE' ) { ... }
Rules are read consecutively and as soon as a rule matches the matching stops.
Cats think they can do everything, and they can:
my $rules = { Cat => { # default rule for any unmatched resource '' => [ # only 1 ruleset with no actual rules, just an action [1] ], } } my $auth = Authorize::Rule->new( rules => $rules ); $auth->check( cats => 'kitchen' ); # 1, success $auth->check( cats => 'bedroom' ); # 1, success
If you don't like the example of cats (what's wrong with you?), try to think of a department (or person) given all access to all resources in your company:
$rules = { Sysadmins => { '' => [ [1] ], }, CEO => { '' => [ [1] ], }, }
Dogs, however, provide less of a problem. Mostly if you tell them they aren't allowed somewhere, they will comply. Dogs can't get on the table. Other than the table, we do want them to have access everywhere.
$rules = { Cat => { '' => [ [1] ], }, Dog => { Table => [ [0] ], # can't go on the table '' => [ [1] ], # otherwise, allow everything }, }
A corporate example might refer to some departments (or persons) having access to some resources while denied everything else, or a certain resource not available to some while all others are.
$rules = { CEO => { Payrolls => [ [0] ], # no access to Payrolls '' => [ [1] ], # access to everything else }, Support => { UserPreferences => [ [1] ], # has access to this UserComplaintHistory => [ [1] ], # and this '' => [ [0] ], # but that's it }, }
This is the most extensive control you can have. This allows you to set permissions based on conditions, such as specific parameters per resource.
Suppose we have no problem for the dogs to walk on that one table we don't like?
my $rules => { Dog => { Table => [ # if the table is owned by someone else, it's okay [ 1, { owner => 'someone-else' } ], # otherwise, no [0], ], '' => [ [1] ], # but generally dogs can go everywhere } }; my $auth = Authorize::Rule->new( rules => $rules ); $auth->is_allowed( Dog => 'Table', { owner => 'me' } ); # 0, fails
You can also specify just the existence (and definess) of keys:
define
my $rules = { Support => { ClientTable => [ [ 1, 'user_id' ], # must have a user id to access the table [0], # otherwise, access denied ] } };
If you want to create an OR condition, all you need is to provide another ruleset:
my $rules = { Dog => { Table => [ [ 1, { carer => 'Jim' } ], # if Jim takes care of the dog [ 1, { carer => 'John' } ], # or if John does [0], # otherwise, no ] } }; $auth->is_allowed( Dog => 'Table', { owner => 'me' } ); # 0, fails $auth->is_allowed( Dog => 'Table', { owner => 'Jim' } ); # 1, succeeds $auth->is_allowed( Dog => 'Table', { owner => 'John' } ); # 1, succeeds
If you want to create an AND condition, just add more rules to the ruleset:
my $rules = { Dog => { Table => [ [ 1, # allow if... { carer => 'John' }, # john is the carer { day => 'Sunday' }, # it's Sunday { clean => 1 }, # you're clean 'tag_id', # and you have a tag id # otherwise, no [0], ] } };
As shown in other examples above, any hash rules can be put in the same hash, so this is equivalent:
my $rules = { Dog => { Table => [ [ 1, # allow if... { carer => 'John', # john is the carer day => 'Sunday', # it's Sunday clean => 1, # you're clean }, 'tag_id', # and you have a tag id # otherwise, no [0], ] } };
The order of rules does not change anything, except how quickly it might mismatch. If you have insane amounts of rules and conditions, it could make a difference, but unlikely.
Optional labels can be applied in order to help structure rulesets and understand which ruleset matched.
my $rules = { Tester => { # Tester's rulesets for any resource '' => [ # regular ruleset [ 1, 'test_mode' ], # if we're in test_mode # labeled ruleset 'has test ID' => [ 1, 'test_id' ], # has a test ID ], }, };
Labeled and unlabeled rulesets can be interchanged freely.
You might ask what if there is no last rule at the end for any other resource?
The answer is simple: the default clause will be used. You can find an explanation of it under ATTRIBUTES.
default
Currently callbacks are not supported, but there are plans for a later version. The issue with callbacks is that you will not be able to serialize the rules.
In case there is no matching rule for the entity/resource/conditions, what would you like to do. The default is to deny (0), but you can change it to allow by default if there is no match.
Authorize::Rule->new( default => 1, # allow by default rules => {...}, ); Authorize::Rule->new( default => -1, # to make sure it's the catch-all rules => {...}, );
A hash reference of your permissions, defined by the specification explained above.
Returns the action for the entity and resource.
Effectively, this is the action key in the result coming from the allowed method described below.
action
allowed
my $result = $auth->allowed( $entity, $resource, $params );
Returns an entire hash containing every piece of information that might be helpful:
entity
resource
params
label
ruleset_idx
The index of the ruleset, starting from 1.
Sawyer X <xsawyerx@cpan.org>
Mickey Nasriachi <mickey@cpan.org>
This software is copyright (c) 2014 by Sawyer X.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Authorize::Rule, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Authorize::Rule
CPAN shell
perl -MCPAN -e shell install Authorize::Rule
For more information on module installation, please visit the detailed CPAN module installation guide.