pyodre 0.0.4

Open Digital Rights Enforcement Framework python implementation

ODRE Framework

Quickstart

To enforce an ODRL policy using the Python Interpreter

policy = """
{
    "@context": "http://www.w3.org/ns/odrl.jsonld",
    "@type": "Offer",
    "uid": "http://example.com/policy:6163",
    "profile": "http://example.com/odrl:profile:10",
    "permission": [{
       "target": "http://example.com/document:1234",
       "assigner": "http://example.com/org:616",
       "action": "distribute",
       "constraint": [{
           "leftOperand": "dateTime",
           "operator": "lt",
           "rightOperand":  { "@value": "2025-01-01", "@type": "xsd:date" }
       }]
   }]
}
"""
usage_decision = ODRE().enforce(policy)
print(usage_decision)

In the case a user wants to activate the DEBUG mode that shows the interpretable policies, the actions and the usage decision the following excerpt must be used. In addition, note that the interpreter can be modified

usage_decision = ODRE().set_debug(True).set_interpreter(PythonInterpreter()).enforce(policy)
print(usage_decision)

Interpolation

The policy templating is based on the Jinja language, it can be used to pass data variables that are not hardcoded in the policy increasing its privacy or it can be used to pass python native functions so they can be expressed in the policy and invoked during the enforcement.

In the following example a variable {{token}} is expressed in the policy and, as left operand, the function {{retrieve_token()}} is used. Note that the value of both is passed to the ODRE object under the parameter interpolations

policy = """
{
    "@context": "http://www.w3.org/ns/odrl.jsonld",
    "@type": "Offer",
    "uid": "http://example.com/policy:6163",
    "profile": "http://example.com/odrl:profile:10",
    "permission": [{
       "target": "http://example.com/document:1234",
       "assigner": "http://example.com/org:616",
       "action": "distribute",
       "constraint": [{
           "leftOperand": "dateTime",
           "operator": "lt",
           "rightOperand":  { "@value": "2025-01-01", "@type": "xsd:date" }
       },{
           "leftOperand": { "@value": "{{retrieve_token()}}" , "@type": "xsd:string" },
           "operator": "eq",
           "rightOperand":  { "@value": "{{token}}", "@type": "xsd:string" }
       }]
   }]
}
"""

def get_token():
    return "AAA"

usage_decision = ODRE().set_debug(True).enforce(policy, interpolations={'token' : 'AAA', 'retrieve_token' : get_token})
print(usage_decision)

Supported features

ODRL operantors

Operators	Implementation status	#
eq	supported	✓
gt	supported	✓
gteq	unsupported	✓
lt	supported	✓
lteq	supported	✓
neq	supported	✓
hasPart	unsupported	✗
isA	unsupported	✗
isAllOf	unsupported	✗
isAnyOf	unsupported	✗
isNoneOf	unsupported	✗
isPartOf	unsupported	✗

ODRL operands

• The available implemented Left Operands from those specified in the ODRL Vocabulary & Expression 2.2 are the following:

Left Operands	Implementation status	#
absolutePosition	unsupported	✗
absoluteSize	unsupported	✗
absoluteSpatialPosition	unsupported	✗
absoluteTemporalPosition	unsupported	✗
count	unsupported	✗
dateTime	unsupported	✗
delayPeriod	unsupported	✗
deliveryChannel	unsupported	✗
device	unsupported	✗
elapsedTime	unsupported	✗
event	unsupported	✗
fileFormat	unsupported	✗
industry	unsupported	✗
language	unsupported	✗
media	unsupported	✗
meteredTime	unsupported	✗
payAmount	unsupported	✗
percentage	unsupported	✗
product	unsupported	✗
purpose	unsupported	✗
recipient	unsupported	✗
relativePosition	unsupported	✗
relativeSize	unsupported	✗
relativeSpatialPosition	unsupported	✗
relativeTemporalPosition	unsupported	✗
resolution	unsupported	✗
spatial	unsupported	✗
spatialCoordinates	unsupported	✗
system	unsupported	✗
systemDevice	unsupported	✗
timeInterval	unsupported	✗
unitOfCount	unsupported	✗
version	unsupported	✗
virtualLocation	unsupported	✗

• The available implemented Right Operands from those specified in the ODRL Vocabulary & Expression 2.2 are the following:

Right Operands	Implementation status	#
policyUsage	unsupported	✗

ODRL actions

• The available implemented Right Operands from those specified in the ODRL Vocabulary & Expression 2.2 are the following:

Actions	Implementation status	#
policyUsage	unsupported	✗

Extensions

In order to include new operators or operands a user must provide their name space and a function prefix for it. For instance, the new function http://XXXXX and its function prefix fnc_. Then, the user must implement the function fnc_XX in the file python functions