Name Tree Schema (#18)

* schema: A first draft on schema tree

* schema: bug fix

* schema: Add schematized trust

* schema: Register, LocalOnly

* schema: SegmentedNode

* schema: Fix RDR

* schema: Policy cannot change Data Name

* schema: Fix raw_packet

* schema: Add document

* examples: Modify the RDR example for tutorial

Author: zjkmxy

AUTHORS.rst

@@ -5,3 +5,4 @@ Authors
 * Zhaoning Kong  <https://jonnykong.com>
 * Eric Newberry  <https://ericnewberry.com>
 * Junxiao Shi    <https://yoursunny.com>
+

docs/index.rst

@@ -17,6 +17,7 @@ Table Of Contents
    src/app
    src/encoding/encoding
    src/security/security
+   src/schema/schema
    src/misc
    src/examples/examples
    src/contribute_support

docs/src/schema/schema.rst

@@ -0,0 +1,44 @@
+:mod:`ndn.schema` package
+============================
+
+Introduction
+------------
+
+The :mod:`ndn.security` package provides an implementation of CNL application framework.
+
+
+CNL Static Namespace Tree
+-------------------------
+
+.. automodule:: ndn.schema.schema_tree
+  :members:
+
+Utils
+-----
+
+.. automodule:: ndn.schema.util
+  :members:
+
+Custom Nodes
+------------
+
+.. automodule:: ndn.schema.simple_node
+  :members:
+
+Policy Types
+------------
+
+.. automodule:: ndn.schema.policy
+  :members:
+
+Trust Policies
+--------------
+
+.. automodule:: ndn.schema.simple_trust
+  :members:
+
+Cache Policies
+--------------
+
+.. automodule:: ndn.schema.simple_cache
+  :members:

examples/rdrnode.py

@@ -0,0 +1,86 @@
+# -----------------------------------------------------------------------------
+# Copyright (C) 2019-2020 Xinyu Ma
+#
+# This file is part of python-ndn.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# -----------------------------------------------------------------------------
+import sys
+import asyncio as aio
+import logging
+from ndn.app import NDNApp
+from ndn.encoding import Name
+from ndn.schema import policy
+from ndn.schema.schema_tree import Node
+from ndn.schema.simple_node import RDRNode
+from ndn.schema.simple_cache import MemoryCache, MemoryCachePolicy
+from ndn.schema.simple_trust import SignedBy
+
+
+logging.basicConfig(format='[{asctime}]{levelname}:{message}',
+                    datefmt='%Y-%m-%d %H:%M:%S',
+                    level=logging.INFO,
+                    style='{')
+app = NDNApp()
+
+
+async def main():
+    if len(sys.argv) <= 1:
+        print(f'Usage: {sys.argv[0]} <name> [<file-path>]')
+        exit(0)
+
+    # Make static tree
+    root = Node()
+    root['/<IDName>/KEY/<KeyID>/self/<CertID>'] = Node()
+    root['/file/<FileName>'] = RDRNode()
+
+    # Set policies
+    id_name = Name.Component.get_value(app.keychain.default_identity().name[0])
+    cache = MemoryCache()
+    root.set_policy(policy.Cache, MemoryCachePolicy(cache))
+    root['/file/<FileName>'].set_policy(
+        policy.DataValidator,
+        SignedBy(root['/<IDName>/KEY/<KeyID>'],
+                 subject_to=lambda _, vars: vars['IDName'] == id_name))
+
+    # Store the certificate
+    cert = app.keychain.default_identity().default_key().default_cert()
+    await cache.save(Name.normalize(cert.name), cert.data)
+
+    # Attach the tree to the face
+    await root.attach(app, '/')
+
+    filename = sys.argv[1]
+    if len(sys.argv) > 2:
+        # If it's the producer
+        filepath = sys.argv[2]
+        print(f'Read {filename} from file {filepath}...')
+        # Provider with file
+        with open(filepath, 'rb') as f:
+            data = f.read()
+            await root.match('/file/' + filename).provide(data, freshness_period=60000)
+        # Wait for it to be cached
+        await aio.sleep(0.1)
+    else:
+        # If it's the producer
+        print(f'Try to fetch {filename}...')
+
+    # The file is ready!
+    data, metadata = await root.match('/file/' + filename).need()
+    print(f'Content size: {len(data)}')
+    print(f'Content: {data[:70]} ...')
+    print(f'Number of segments: {metadata["block_count"]}')
+    print(f'Serving {filename}')
+
+if __name__ == '__main__':
+    app.run_forever(after_start=main())

src/ndn/schema/__init__.py

@@ -0,0 +1,117 @@
+import abc
+from typing import Optional
+from ..encoding import SignaturePtrs, FormalName, InterestParam, BinaryStr
+from ..encoding.signer import Signer
+from ..types import Validator
+
+
+class Policy:
+    """
+    Policy is an annotation attached to a node.
+    """
+    def __init__(self):
+        self.node = None
+
+
+class Cache(Policy, metaclass=abc.ABCMeta):
+    """
+    Cache policy determines how Data packets are stored.
+    """
+    @abc.abstractmethod
+    async def search(self, match, name: FormalName, param: InterestParam):
+        pass
+
+    @abc.abstractmethod
+    async def save(self, match, name: FormalName, packet: BinaryStr):
+        pass
+
+
+class InterestValidator(Policy, metaclass=abc.ABCMeta):
+    """
+    InterestValidator policy describes how to verify an Interest packet.
+    """
+    @abc.abstractmethod
+    async def validate(self, match, sig_ptrs: SignaturePtrs) -> bool:
+        pass
+
+
+class DataValidator(Policy, metaclass=abc.ABCMeta):
+    """
+    DataValidator policy describes how to verify a Data packet.
+    """
+    @abc.abstractmethod
+    def get_validator(self, match) -> Validator:
+        pass
+
+
+class Signing(Policy, metaclass=abc.ABCMeta):
+    """
+    Signing policy gives a signer used to sign a packet.
+    When a user uses signing policy, he needs to specify whether its
+    :class:`InterestSigning` or :class:`DataSigning`.
+    """
+    @abc.abstractmethod
+    async def get_signer(self, match) -> Signer:
+        pass
+
+
+class InterestSigning(Signing, metaclass=abc.ABCMeta):
+    """
+    InterestSigning policy is a type used to indicate the Interest signer.
+    Used as the type argument of set_policy.
+    """
+    pass
+
+
+class DataSigning(Signing, metaclass=abc.ABCMeta):
+    """
+    DataSigning policy is a type used to indicate the Data signer.
+    Used as the type argument of set_policy.
+    """
+    pass
+
+
+class Encryption(Policy, metaclass=abc.ABCMeta):
+    """
+    Encryption policy encrypts and decrypts content.
+    When a user uses encryption policy, he needs to specify whether its
+    :class:`InterestEncryption` or :class:`DataEncryption`.
+    """
+    @abc.abstractmethod
+    async def decrypt(self, match, content: BinaryStr) -> Optional[BinaryStr]:
+        pass
+
+    @abc.abstractmethod
+    async def encrypt(self, match, content: BinaryStr) -> Optional[BinaryStr]:
+        pass
+
+
+class InterestEncryption(Encryption, metaclass=abc.ABCMeta):
+    """
+    InterestSigning policy is a type used to indicate the Interest encryption policy.
+    Used as the type argument of set_policy.
+    """
+    pass
+
+
+class DataEncryption(Encryption, metaclass=abc.ABCMeta):
+    """
+    DataEncryption policy is a type used to indicate the Data encryption policy.
+    Used as the type argument of set_policy.
+    """
+    pass
+
+
+class LocalOnly(Policy):
+    """
+    LocalOnly means the Data should be stored in the local storage.
+    It prevents the node from sending Interest packets.
+    """
+    pass
+
+
+class Register(Policy):
+    """
+    Register policy indicates the node should be registered as a prefix in the forwarder.
+    """
+    pass