Merge pull request #12 from jimbobbennett/master

Change from library dependency to code to save 37K of memory

Author: brentru

README.rst

@@ -45,16 +45,12 @@ 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 HMAC <https://github.com/jimbobbennett/CircuitPython_HMAC>`_
-* `CircuitPython Parse <https://github.com/jimbobbennett/CircuitPython_Parse>`_
+* `Adafruit CircuitPython Requests <https://github.com/adafruit/Adafruit_CircuitPython_Requests>`_
+* `Adafruit CircuitPython BinASCII <https://github.com/adafruit/Adafruit_CircuitPython_Binascii>`_
 
 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

@@ -32,14 +32,12 @@
 import gc
 import json
 import time
-import circuitpython_base64 as base64
-import circuitpython_hmac as hmac
-import circuitpython_parse as parse
 import adafruit_requests as requests
 import adafruit_logging as logging
 from adafruit_logging import Logger
-import adafruit_hashlib as hashlib
 from . import constants
+from .quote import quote
+from .keys import compute_derived_symmetric_key
 
 # Azure HTTP error status codes
 AZURE_HTTP_ERROR_CODES = [400, 401, 404, 403, 412, 429, 500]
@@ -89,17 +87,6 @@ def __init__(self, socket, id_scope: str, device_id: str, key: str, logger: Logg
 
         requests.set_socket(socket)
 
-    @staticmethod
-    def compute_derived_symmetric_key(secret: str, msg: str) -> bytes:
-        """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
-        """
-        secret = base64.b64decode(secret)
-        return base64.b64encode(hmac.new(secret, msg=msg.encode("utf8"), digestmod=hashlib.sha256).digest())
-
     def _loop_assign(self, operation_id, headers) -> str:
         uri = "https://%s/%s/registrations/%s/operations/%s?api-version=%s" % (
             constants.DPS_END_POINT,
@@ -109,9 +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()
@@ -205,8 +191,8 @@ def register_device(self, expiry: int) -> str:
         """
         # pylint: disable=C0103
         sr = self._id_scope + "%2Fregistrations%2F" + self._device_id
-        sig_no_encode = DeviceRegistration.compute_derived_symmetric_key(self._key, sr + "\n" + str(expiry))
-        sig_encoded = parse.quote(sig_no_encode, "~()*!.'")
+        sig_no_encode = compute_derived_symmetric_key(self._key, sr + "\n" + str(expiry))
+        sig_encoded = quote(sig_no_encode, "~()*!.'")
         auth_string = "SharedAccessSignature sr=" + sr + "&sig=" + sig_encoded + "&se=" + str(expiry) + "&skn=registration"
 
         headers = {
@@ -226,13 +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: