def test_partial_constraint(polar):
class User:
pass
class Post:
pass
polar.register_class(User)
polar.register_class(Post)
polar.load_str("f(x: User) if x.user = 1;")
polar.load_str("f(x: Post) if x.post = 1;")
partial = Partial("x", TypeConstraint("User"))
results = polar.query_rule("f", partial)
first = next(results)["bindings"]["x"]
and_args = unwrap_and(first)
assert len(and_args) == 2
assert and_args[0] == Expression("Isa", [Variable("_this"), Pattern("User", {})])
unify = unwrap_and(and_args[1])
assert unify == Expression(
"Unify", [Expression("Dot", [Variable("_this"), "user"]), 1]
)
with pytest.raises(StopIteration):
next(results)
def test_register_constants_with_decorator():
@polar_class
class RegisterDecoratorTest:
x = 1
p = Polar()
p.load_str("foo_rule(x: RegisterDecoratorTest, y) if y = 1;")
p.load_str("foo_class_attr(y) if y = RegisterDecoratorTest.x;")
assert (
next(p.query_rule("foo_rule", RegisterDecoratorTest(), Variable("y")))[
"bindings"
]["y"]
== 1
)
assert next(p.query_rule("foo_class_attr", Variable("y")))["bindings"]["y"] == 1
p = Polar()
p.load_str("foo_rule(x: RegisterDecoratorTest, y) if y = 1;")
p.load_str("foo_class_attr(y) if y = RegisterDecoratorTest.x;")
assert (
next(p.query_rule("foo_rule", RegisterDecoratorTest(), Variable("y")))[
"bindings"
]["y"]
== 1
)
assert next(p.query_rule("foo_class_attr", Variable("y")))["bindings"]["y"] == 1
def test_partial(polar):
polar.load_str("f(1);")
polar.load_str("f(x) if x = 1 and x = 2;")
results = polar.query_rule("f", Partial("x"))
first = next(results)
x = first["bindings"]["x"]
assert unwrap_and(x) == Expression("Unify", [Variable("_this"), 1])
second = next(results)
x = second["bindings"]["x"]
# Top level should be and
and_args = unwrap_and(x)
assert and_args[0] == Expression("Unify", [Variable("_this"), 1])
polar.load_str("g(x) if x.bar = 1 and x.baz = 2;")
results = polar.query_rule("g", Partial("x"))
first = next(results)
x = first["bindings"]["x"]
and_args = unwrap_and(x)
assert len(and_args) == 2
assert unwrap_and(and_args[0]) == Expression(
"Unify", [Expression("Dot", [Variable("_this"), "bar"]), 1]
)
assert unwrap_and(and_args[1]) == Expression(
"Unify", [Expression("Dot", [Variable("_this"), "baz"]), 2]
)
def test_partial(polar):
polar.load_str("f(1);")
polar.load_str("f(x) if x = 1 and x = 2;")
results = polar.query_rule("f", Variable("x"), accept_expression=True)
first = next(results)
x = first["bindings"]["x"]
assert x == 1
with pytest.raises(StopIteration):
next(results)
polar.load_str("g(x) if x.bar = 1 and x.baz = 2;")
results = polar.query_rule("g", Variable("x"), accept_expression=True)
first = next(results)
x = first["bindings"]["x"]
and_args = unwrap_and(x)
assert len(and_args) == 2
assert and_args[0] == Expression(
"Unify", [1, Expression("Dot", [Variable("_this"), "bar"])])
assert and_args[1] == Expression(
"Unify", [2, Expression("Dot", [Variable("_this"), "baz"])])
def test_partial_unification(polar):
polar.load_str("f(x, y) if x = y;")
x = Variable("x")
y = Variable("y")
results = polar.query_rule("f", x, y)
result = next(results)["bindings"]
assert result["x"] == y
assert result["y"] == x
with pytest.raises(StopIteration):
next(results)
def test_model_registration():
"""Test that models are automatically registered with the policy."""
from test_app import models
from oso import Variable
assert (next(
Oso.query_rule("models", models.TestRegistration(),
Variable("x")))["bindings"]["x"] == 1)
assert (next(
Oso.query_rule("models", models.TestRegistration2(),
Variable("x")))["bindings"]["x"] == 2)
def test_datetime(polar, query):
# test datetime comparison
t1 = datetime(2020, 5, 25)
t2 = datetime.now()
t3 = datetime(2030, 5, 25)
t4 = datetime(2020, 5, 26)
polar.load_str("lt(a, b) if a < b;")
assert query(Predicate("lt", [t1, t2]))
assert not query(Predicate("lt", [t2, t1]))
# test creating datetime from polar
polar.load_str("dt(x) if x = new Datetime(year: 2020, month: 5, day: 25);")
assert query(Predicate("dt", [Variable("x")])) == [{
"x":
datetime(2020, 5, 25)
}]
polar.load_str("ltnow(x) if x < Datetime.now();")
assert query(Predicate("ltnow", [t1]))
assert not query(Predicate("ltnow", [t3]))
polar.load_str(
"timedelta(a: Datetime, b: Datetime) if a.__sub__(b) == new Timedelta(days: 1);"
)
assert query(Predicate("timedelta", [t4, t1]))
def test_partial_rule_filtering(polar):
class A:
def __init__(self):
self.c = C()
class B:
pass
class C:
pass
class D:
pass
polar.register_class(A)
polar.register_class(B)
polar.register_class(C)
polar.register_class(D)
polar.load_str("""f(x: A) if g(x.c);
g(_: B);
g(_: C);
g(_: D);""")
x = Variable("x")
with pytest.raises(exceptions.PolarRuntimeError) as e:
next(polar.query_rule("f", x, bindings={x: TypeConstraint(x, "A")}))
assert str(e.value) == "Cannot generically walk fields of a Python class"
def test_dot_path():
non_dot = Expression("And", [])
assert dot_path(non_dot) == ()
this = Variable("_this")
assert dot_path(this) == (this, )
var = Variable("x")
assert dot_path(var) == (var, )
single_dot = Expression("Dot", [this, "created_by"])
assert dot_path(single_dot) == (this, "created_by")
double_dot = Expression("Dot", [single_dot, "username"])
assert dot_path(double_dot) == (this, "created_by", "username")
triple_dot = Expression("Dot", [double_dot, "first"])
assert dot_path(triple_dot) == (this, "created_by", "username", "first")
def test_dot_path():
single = Expression("Dot", [Variable("_this"), "created_by"])
assert dot_path(single) == ("created_by", )
double = Expression("Dot", [single, "username"])
assert dot_path(double) == ("created_by", "username")
triple = Expression("Dot", [double, "first"])
assert dot_path(triple) == ("created_by", "username", "first")
def test_query(load_file, polar, query):
"""Test that queries work with variable arguments"""
load_file(Path(__file__).parent / "test_file.polar")
# plaintext polar query: query("f(x)") == [{"x": 1}, {"x": 2}, {"x": 3}]
assert query(Predicate(name="f", args=[Variable("a")])) == [
{"a": 1},
{"a": 2},
{"a": 3},
]
def test_partial_unification():
Oso.load_str("f(x, y) if x = y and x = 1;")
results = Oso.query_rule("f",
Variable("x"),
Variable("y"),
accept_expression=True)
first = next(results)["bindings"]
assert first["x"] == 1
assert first["y"] == 1
with pytest.raises(StopIteration):
next(results)
Oso.load_str("g(x, y) if x = y and y > 1;")
results = Oso.query_rule("g",
Variable("x"),
Variable("y"),
accept_expression=True)
first = next(results)["bindings"]
# TODO not ideal that these are swapped in order (y = x) not (x = y).
# this is a hard case, we want the (y > 1) to be this in both cases AND keep the x = y.
assert first["x"] == Expression(
"And",
[
Expression("Unify",
[Variable("y"), Variable("_this")]),
Expression("Gt", [Variable("y"), 1]),
],
)
assert first["y"] == Expression(
"And",
[
Expression("Unify",
[Variable("_this"), Variable("x")]),
Expression("Gt", [Variable("_this"), 1]),
],
)
def get_allowed_actions(self,
actor,
resource,
allow_wildcard=False) -> list:
"""Determine the actions ``actor`` is allowed to take on ``resource``.
Collects all actions allowed by allow rules in the Polar policy for the
given combination of actor and resource.
:param actor: The actor for whom to collect allowed actions
:param resource: The resource being accessed
:param allow_wildcard: Flag to determine behavior if the policy \
includes a wildcard action. E.g., a rule allowing any action: \
``allow(_actor, _action, _resource)``. If ``True``, the method will \
return ``["*"]``, if ``False``, the method will raise an exception.
:type allow_wildcard: bool
:return: A list of the unique allowed actions.
"""
results = self.query_rule("allow", actor, Variable("action"), resource)
actions = set()
for result in results:
action = result.get("bindings").get("action")
if isinstance(action, Variable):
if not allow_wildcard:
raise exceptions.OsoError(
"""The result of get_allowed_actions() contained an
"unconstrained" action that could represent any
action, but allow_wildcard was set to False. To fix,
set allow_wildcard to True and compare with the "*"
string.""")
else:
return ["*"]
actions.add(action)
return list(actions)
def test_partial_unification():
Oso.load_str("f(x, y) if x = y and x = 1;")
results = Oso.query_rule("f",
Variable("x"),
Variable("y"),
accept_expression=True)
first = next(results)["bindings"]
assert first["x"] == 1
assert first["y"] == 1
with pytest.raises(StopIteration):
next(results)
Oso.load_str("g(x, y) if x = y and y > 1;")
results = Oso.query_rule("g",
Variable("x"),
Variable("y"),
accept_expression=True)
first = next(results)["bindings"]
assert first["x"] == Expression("And",
[Expression("Gt", [Variable("_this"), 1])])
assert first["y"] == Expression("And",
[Expression("Gt", [Variable("_this"), 1])])
def authorize_model(oso: Oso, actor, action, session: Session, model):
"""Return SQLAlchemy expression that applies the policy to ``model``.
Executing this query will return only authorized objects. If the request is
not authorized, a query that always contains no result will be returned.
:param oso: The oso class to use for evaluating the policy.
:param actor: The actor to authorize.
:param action: The action to authorize.
:param session: The SQLAlchemy session.
:param model: The model to authorize, must be a SQLAlchemy model or alias.
"""
def get_field_type(model, field):
try:
field = getattr(model, field)
except AttributeError:
raise PolarRuntimeError(f"Cannot get property {field} on {model}.")
try:
return field.entity.class_
except AttributeError as e:
raise PolarRuntimeError(
f"Cannot determine type of {field} on {model}.") from e
oso.host.get_field = get_field_type
try:
mapped_class = inspect(model, raiseerr=True).class_
except AttributeError:
raise TypeError(f"Expected a model; received: {model}")
resource = Variable("resource")
constraint = TypeConstraint(resource, polar_model_name(mapped_class))
results = oso.query_rule(
"allow",
actor,
action,
resource,
bindings={resource: constraint},
accept_expression=True,
)
combined_filter = None
has_result = False
for result in results:
has_result = True
resource_partial = result["bindings"]["resource"]
filter = partial_to_filter(resource_partial,
session,
model,
get_model=oso.get_class)
if combined_filter is None:
combined_filter = filter
else:
combined_filter = combined_filter | filter
if not has_result:
return sql.false()
return combined_filter
def test_unexpected_expression(polar):
"""Ensure expression type raises error from core."""
polar.load_str("f(x) if x > 2;")
with pytest.raises(UnexpectedPolarTypeError):
next(polar.query_rule("f", Variable("x")))
