Removing other dependencies and moving to minimal code

Author: Jim Bennett

README.rst

@@ -45,15 +45,11 @@ This driver depends on:
 
 * `Adafruit CircuitPython <https://github.com/adafruit/circuitpython>`_
 * `Adafruit CircuitPython MiniMQTT <https://github.com/adafruit/Adafruit_CircuitPython_MiniMQTT>`_
-
-* `CircuitPython Base64 <https://github.com/jimbobbennett/CircuitPython_Base64>`_
-* `CircuitPython Parse <https://github.com/jimbobbennett/CircuitPython_Parse>`_
+* `Adafruit CircuitPython Requests <https://github.com/adafruit/Adafruit_CircuitPython_Requests>`_
 
 Please ensure all dependencies are available on the CircuitPython filesystem.
 This is easily achieved by downloading
-`the Adafruit library and driver bundle <https://github.com/adafruit/Adafruit_CircuitPython_Bundle>`_
-and
-`the CircuitPython community library and driver bundle <https://github.com/adafruit/CircuitPython_Community_Bundle>`_
+`the Adafruit library and driver bundle <https://github.com/adafruit/Adafruit_CircuitPython_Bundle>`_.
 
 Usage Example
 =============

adafruit_azureiot/__init__.py

@@ -37,9 +37,6 @@
 
 * Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
 * Adafruit's ESP32SPI library: https://github.com/adafruit/Adafruit_CircuitPython_ESP32SPI
-* Community HMAC library: https://github.com/jimbobbennett/CircuitPython_HMAC
-* Community base64 library: https://github.com/jimbobbennett/CircuitPython_Base64
-* Community Parse library: https://github.com/jimbobbennett/CircuitPython_Parse
 """
 
 from .iot_error import IoTError

adafruit_azureiot/base64.py

@@ -0,0 +1,81 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2020 Jim Bennett
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+"""
+`base64`
+================================================================================
+
+RFC 3548: Base64 Data Encodings
+
+
+* Author(s): Jim Bennett
+
+Implementation Notes
+--------------------
+
+**Software and Dependencies:**
+
+* Adafruit CircuitPython firmware for the supported boards:
+  https://github.com/adafruit/circuitpython/releases
+
+"""
+
+import adafruit_binascii as binascii
+
+__all__ = ["b64encode", "b64decode"]
+
+
+def _bytes_from_decode_data(data: str):
+    try:
+        return data.encode("ascii")
+    except:
+        raise ValueError("string argument should contain only ASCII characters")
+
+
+def b64encode(toencode: bytes) -> bytes:
+    """Encode a byte string using Base64.
+
+    toencode is the byte string to encode.  Optional altchars must be a byte
+    string of length 2 which specifies an alternative alphabet for the
+    '+' and '/' characters.  This allows an application to
+    e.g. generate url or filesystem safe Base64 strings.
+
+    The encoded byte string is returned.
+    """
+    # Strip off the trailing newline
+    return binascii.b2a_base64(toencode)[:-1]
+
+
+def b64decode(todecode: str) -> bytes:
+    """Decode a Base64 encoded byte string.
+
+    todecode is the byte string to decode.  Optional altchars must be a
+    string of length 2 which specifies the alternative alphabet used
+    instead of the '+' and '/' characters.
+
+    The decoded string is returned.  A binascii.Error is raised if todecode is
+    incorrectly padded.
+
+    If validate is False (the default), non-base64-alphabet characters are
+    discarded prior to the padding check.  If validate is True,
+    non-base64-alphabet characters in the input result in a binascii.Error.
+    """
+    return binascii.a2b_base64(_bytes_from_decode_data(todecode))

adafruit_azureiot/device_registration.py

@@ -32,11 +32,11 @@
 import gc
 import json
 import time
-import circuitpython_parse as parse
 import adafruit_requests as requests
 import adafruit_logging as logging
 from adafruit_logging import Logger
 from . import constants
+from .quote import quote
 from .keys import compute_derived_symmetric_key
 
 # Azure HTTP error status codes
@@ -96,9 +96,8 @@ def _loop_assign(self, operation_id, headers) -> str:
             constants.DPS_API_VERSION,
         )
         self._logger.info("- iotc :: _loop_assign :: " + uri)
-        target = parse.urlparse(uri)
 
-        response = self._run_get_request_with_retry(target.geturl(), headers)
+        response = self._run_get_request_with_retry(uri, headers)
 
         try:
             data = response.json()
@@ -193,7 +192,7 @@ def register_device(self, expiry: int) -> str:
         # pylint: disable=C0103
         sr = self._id_scope + "%2Fregistrations%2F" + self._device_id
         sig_no_encode = compute_derived_symmetric_key(self._key, sr + "\n" + str(expiry))
-        sig_encoded = parse.quote(sig_no_encode, "~()*!.'")
+        sig_encoded = quote(sig_no_encode, "~()*!.'")
         auth_string = "SharedAccessSignature sr=" + sr + "&sig=" + sig_encoded + "&se=" + str(expiry) + "&skn=registration"
 
         headers = {
@@ -213,13 +212,12 @@ def register_device(self, expiry: int) -> str:
             self._device_id,
             constants.DPS_API_VERSION,
         )
-        target = parse.urlparse(uri)
 
         self._logger.info("Connecting...")
-        self._logger.info("URL: " + target.geturl())
+        self._logger.info("URL: " + uri)
         self._logger.info("body: " + json.dumps(body))
 
-        response = self._run_put_request_with_retry(target.geturl(), body, headers)
+        response = self._run_put_request_with_retry(uri, body, headers)
 
         data = None
         try:

adafruit_azureiot/hmac.py

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 """
-`circuitpython_hmac`
+`HMAC`
 ================================================================================
 
 HMAC (Keyed-Hashing for Message Authentication) Python module.

adafruit_azureiot/iot_mqtt.py

@@ -33,10 +33,10 @@
 import time
 import adafruit_minimqtt as minimqtt
 from adafruit_minimqtt import MQTT
-import circuitpython_parse as parse
 import adafruit_logging as logging
 from .iot_error import IoTError
 from .keys import compute_derived_symmetric_key
+from .quote import quote
 from . import constants
 
 # pylint: disable=R0903
@@ -108,7 +108,7 @@ def _gen_sas_token(self) -> str:
         token_expiry = int(time.time() + self._token_expires)
         uri = self._hostname + "%2Fdevices%2F" + self._device_id
         signed_hmac_sha256 = compute_derived_symmetric_key(self._key, uri + "\n" + str(token_expiry))
-        signature = parse.quote(signed_hmac_sha256, "~()*!.'")
+        signature = quote(signed_hmac_sha256, "~()*!.'")
         if signature.endswith("\n"):  # somewhere along the crypto chain a newline is inserted
             signature = signature[:-1]
         token = "SharedAccessSignature sr={}&sig={}&se={}".format(uri, signature, token_expiry)
@@ -447,6 +447,7 @@ def loop(self) -> None:
             return
 
         self._mqtts.loop()
+        gc.collect()
 
     def send_device_to_cloud_message(self, message, system_properties: dict = None) -> None:
         """Send a device to cloud message from this device to Azure IoT Hub

adafruit_azureiot/keys.py

@@ -1,11 +1,32 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2020 Jim Bennett
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
 """Computes a derived symmetric key from a secret and a message
 :param str secret: The secret to use for the key
 :param str msg: The message to use for the key
 :returns: The derived symmetric key
 :rtype: bytes
 """
 
-import circuitpython_base64 as base64
+from .base64 import b64decode, b64encode
 from .hmac import new_hmac
 
 
@@ -16,5 +37,4 @@ def compute_derived_symmetric_key(secret: str, msg: str) -> bytes:
     :returns: The derived symmetric key
     :rtype: bytes
     """
-    secret = base64.b64decode(secret)
-    return base64.b64encode(new_hmac(secret, msg=msg.encode("utf8")).digest())
+    return b64encode(new_hmac(b64decode(secret), msg=msg.encode("utf8")).digest())

adafruit_azureiot/mpy.sh

@@ -0,0 +1,11 @@
+~/Downloads/mpy-cross/mpy-cross __init__.py
+~/Downloads/mpy-cross/mpy-cross constants.py
+~/Downloads/mpy-cross/mpy-cross device_registration.py
+~/Downloads/mpy-cross/mpy-cross hmac.py
+~/Downloads/mpy-cross/mpy-cross iot_error.py
+~/Downloads/mpy-cross/mpy-cross iot_mqtt.py
+~/Downloads/mpy-cross/mpy-cross iotcentral_device.py
+~/Downloads/mpy-cross/mpy-cross iothub_device.py
+~/Downloads/mpy-cross/mpy-cross keys.py
+~/Downloads/mpy-cross/mpy-cross quote.py
+~/Downloads/mpy-cross/mpy-cross base64.py

adafruit_azureiot/quote.py

@@ -0,0 +1,138 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2020 Jim Bennett
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+"""
+`quote`
+================================================================================
+
+The quote function %-escapes all characters that are neither in the
+unreserved chars ("always safe") nor the additional chars set via the
+safe arg.
+
+"""
+_ALWAYS_SAFE = frozenset(b"ABCDEFGHIJKLMNOPQRSTUVWXYZ" b"abcdefghijklmnopqrstuvwxyz" b"0123456789" b"_.-~")
+_ALWAYS_SAFE_BYTES = bytes(_ALWAYS_SAFE)
+SAFE_QUOTERS = {}
+
+
+def quote(bytes_val: bytes, safe="/"):
+    """The quote function %-escapes all characters that are neither in the
+    unreserved chars ("always safe") nor the additional chars set via the
+    safe arg.
+    """
+    if not isinstance(bytes_val, (bytes, bytearray)):
+        raise TypeError("quote_from_bytes() expected bytes")
+    if not bytes_val:
+        return ""
+    if isinstance(safe, str):
+        # Normalize 'safe' by converting to bytes and removing non-ASCII chars
+        safe = safe.encode("ascii", "ignore")
+    else:
+        safe = bytes([char for char in safe if char < 128])
+    if not bytes_val.rstrip(_ALWAYS_SAFE_BYTES + safe):
+        return bytes_val.decode()
+    try:
+        quoter = SAFE_QUOTERS[safe]
+    except KeyError:
+        SAFE_QUOTERS[safe] = quoter = Quoter(safe).__getitem__
+    return "".join([quoter(char) for char in bytes_val])
+
+
+# pylint: disable=C0103
+class defaultdict:
+    """
+    Default Dict Implementation.
+
+    Defaultdcit that returns the key if the key is not found in dictionnary (see
+    unswap in karma-lib):
+    >>> d = defaultdict(default=lambda key: key)
+    >>> d['foo'] = 'bar'
+    >>> d['foo']
+    'bar'
+    >>> d['baz']
+    'baz'
+    DefaultDict that returns an empty string if the key is not found (see
+    prefix in karma-lib for typical usage):
+    >>> d = defaultdict(default=lambda key: '')
+    >>> d['foo'] = 'bar'
+    >>> d['foo']
+    'bar'
+    >>> d['baz']
+    ''
+    Representation of a default dict:
+    >>> defaultdict([('foo', 'bar')])
+    defaultdict(None, {'foo': 'bar'})
+    """
+
+    @staticmethod
+    # pylint: disable=W0613
+    def __new__(cls, default_factory=None, **kwargs):
+        self = super(defaultdict, cls).__new__(cls)
+        # pylint: disable=C0103
+        self.d = {}
+        return self
+
+    def __init__(self, default_factory=None, **kwargs):
+        self.d = kwargs
+        self.default_factory = default_factory
+
+    def __getitem__(self, key):
+        try:
+            return self.d[key]
+        except KeyError:
+            val = self.__missing__(key)
+            self.d[key] = val
+            return val
+
+    def __setitem__(self, key, val):
+        self.d[key] = val
+
+    def __delitem__(self, key):
+        del self.d[key]
+
+    def __contains__(self, key):
+        return key in self.d
+
+    def __missing__(self, key):
+        if self.default_factory is None:
+            raise KeyError(key)
+        return self.default_factory()
+
+
+class Quoter(defaultdict):
+    """A mapping from bytes (in range(0,256)) to strings.
+
+    String values are percent-encoded byte values, unless the key < 128, and
+    in the "safe" set (either the specified safe set, or default set).
+    """
+
+    # Keeps a cache internally, using defaultdict, for efficiency (lookups
+    # of cached keys don't call Python code at all).
+    def __init__(self, safe):
+        """safe: bytes object."""
+        super(Quoter, self).__init__()
+        self.safe = _ALWAYS_SAFE.union(safe)
+
+    def __missing__(self, b):
+        # Handle a cache miss. Store quoted string in cache and return.
+        res = chr(b) if b in self.safe else "%{:02X}".format(b)
+        self[b] = res
+        return res