python实现ABAC

ABAC（Attribute-Based Access Control）是一种基于属性的访问控制，可以根据用户的属性来控制对资源的访问。在Python中实现ABAC，可以使用PyABAC库。

首先，需要定义一些实体和属性。比如，我们定义一个用户实体和一个文件资源实体，用户实体拥有一个role属性，文件资源实体拥有一个owner属性。

from pyabac import Policy, AccessRequest, Action, Attribute, Access

# Define entities and attributes
class User:
    def __init__(self, role):
        self.role = role

class FileResource:
    def __init__(self, owner):
        self.owner = owner

# Define policies
policy = Policy(
    "file access policy",
    {
        "attributes": {
            "role": Attribute(str),
            "owner": Attribute(str),
        },
        "rules": {
            "allow owner to read": {
                "target": {
                    "entity": "file",
                    "attribute": "owner",
                },
                "effect": "permit",
                "condition": {
                    "equals": {
                        "attribute": "user.role",
                        "value": "owner",
                    },
                },
                "actions": [
                    "read",
                ],
            },
            "allow owner to write": {
                "target": {
                    "entity": "file",
                    "attribute": "owner",
                },
                "effect": "permit",
                "condition": {
                    "equals": {
                        "attribute": "user.role",
                        "value": "owner",
                    },
                },
                "actions": [
                    "write",
                ],
            },
            "deny others": {
                "target": {
                    "entity": "file",
                },
                "effect": "deny",
                "condition": {
                    "not": {
                        "equals": {
                            "attribute": "user.role",
                            "value": "owner",
                        },
                    },
                },
                "actions": [
                    "read",
                    "write",
                ],
            },
        },
    },
)

然后，我们可以创建一个AccessRequest对象来请求访问资源。AccessRequest对象包含了用户实体和文件资源实体的属性。

# Create access request
user = User("owner")
file = FileResource("owner")
access_request = AccessRequest(
    user=user,
    resource=file,
    action=Action.READ,
)

最后，我们可以使用Policy对象来判断用户是否有访问资源的权限。

# Check access
access = policy.evaluate(access_request)
if access == Access.ALLOW:
    print("Access granted")
else:
    print("Access denied")

完整代码示例：

from pyabac import Policy, AccessRequest, Action, Attribute, Access

# Define entities and attributes
class User:
    def __init__(self, role):
        self.role = role

class FileResource:
    def __init__(self, owner):
        self.owner = owner

# Define policies
policy = Policy(
    "file access policy",
    {
        "attributes": {
            "role": Attribute(str),
            "owner": Attribute(str),
        },
        "rules": {
            "allow owner to read": {
                "target": {
                    "entity": "file",
                    "attribute": "owner",
                },
                "effect": "permit",
                "condition": {
                    "equals": {
                        "attribute": "user.role",
                        "value": "owner",
                    },
                },
                "actions": [
                    "read",
                ],
            },
            "allow owner to write": {
                "target": {
                    "entity": "file",
                    "attribute": "owner",
                },
                "effect": "permit",
                "condition": {
                    "equals": {
                        "attribute": "user.role",
                        "value": "owner",
                    },
                },
                "actions": [
                    "write",
                ],
            },
            "deny others": {
                "target": {
                    "entity": "file",
                },
                "effect": "deny",
                "condition": {
                    "not": {
                        "equals": {
                            "attribute": "user.role",
                            "value": "owner",
                        },
                    },
                },
                "actions": [
                    "read",
                    "write",
                ],
            },
        },
    },
)

# Create access request
user = User("owner")
file = FileResource("owner")
access_request = AccessRequest(
    user=user,
    resource=file,
    action=Action.READ,
)

# Check access
access = policy.evaluate(access_request)
if access == Access.ALLOW:
    print("Access granted")
else:
    print("Access denied")