From ee214a1470db58d60b1d7612ed33691ad7cfd370 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Diego=20Elio=20Petten=C3=B2?= <flameeyes@flameeyes.com>
Date: Wed, 3 Mar 2021 13:48:38 +0000
Subject: Allow selecting which encoding to use for decoding text commands.

The FreeStyle Libre at least allows patient names and other strings to
be set in UTF-8 so there is no reason to force ascii everywhere.

Instead, allow the session to define an encoding for ease of integration
with downstream tools.
---
 freestyle_hid/_session.py          | 20 +++++++++-----------
 freestyle_hid/tools/hid_console.py | 10 +++++++++-
 2 files changed, 18 insertions(+), 12 deletions(-)

(limited to 'freestyle_hid')

diff --git a/freestyle_hid/_session.py b/freestyle_hid/_session.py
index aab1f6c..527a5fc 100644
--- a/freestyle_hid/_session.py
+++ b/freestyle_hid/_session.py
@@ -118,11 +118,13 @@ class Session:
         device_path: Optional[pathlib.Path],
         text_message_type: int,
         text_reply_message_type: int,
+        encoding: str = "ascii",
     ) -> None:
         self._handle = HidWrapper.open(device_path, ABBOTT_VENDOR_ID, product_id)
 
         self._text_message_type = text_message_type
         self._text_reply_message_type = text_reply_message_type
+        self._encoding = encoding
 
     def connect(self):
         """Open connection to the device, starting the knocking sequence."""
@@ -191,7 +193,7 @@ class Session:
 
         return message
 
-    def _send_text_command(self, command: bytes) -> bytes:
+    def _send_text_command_raw(self, command: bytes) -> bytes:
         """Send a command to the device that expects a text reply."""
         self.send_command(self._text_message_type, command)
 
@@ -226,12 +228,8 @@ class Session:
 
         return message
 
-    def send_text_command(self, command: bytes) -> bytes:
-        # If there is anything in the response that is not ASCII-safe, this is
-        # probably in the patient name. The Windows utility does not seem to
-        # validate those, so just replace anything non-ASCII with the correct
-        # unknown codepoint.
-        return self._send_text_command(command).decode("ascii", "replace")
+    def send_text_command(self, command: bytes) -> str:
+        return self._send_text_command_raw(command).decode(self._encoding, "replace")
 
     def query_multirecord(self, command: bytes) -> Iterator[Sequence[str]]:
         """Queries for, and returns, "multirecords" results.
@@ -250,7 +248,7 @@ class Session:
           A CSV reader object that returns a record for each line in the
           reply buffer.
         """
-        message = self._send_text_command(command)
+        message = self._send_text_command_raw(command)
         logging.debug(f"Received multi-record message:\n{message!r}")
         if message == b"Log Empty\r\n":
             return iter(())
@@ -259,12 +257,12 @@ class Session:
         if not match:
             raise CommandError(repr(message))
 
-        records_str = match.group("message")
-        _verify_checksum(records_str, match.group("checksum"))
+        records_raw = match.group("message")
+        _verify_checksum(records_raw, match.group("checksum"))
 
         # Decode here with replacement; the software does not deal with UTF-8
         # correctly, and appears to truncate incorrectly the strings.
-        records_str = records_str.decode("utf-8", "replace")
+        records_str = records_raw.decode(self._encoding, "replace")
 
         logging.debug(f"Received multi-record string: {records_str}")
 
diff --git a/freestyle_hid/tools/hid_console.py b/freestyle_hid/tools/hid_console.py
index b3b3fee..2c395bd 100755
--- a/freestyle_hid/tools/hid_console.py
+++ b/freestyle_hid/tools/hid_console.py
@@ -39,6 +39,13 @@ click_log.basic_config(logger)
     type=int,
     help="Optional product ID (in alternative to the device path)",
 )
+@click.option(
+    "--encoding",
+    "-e",
+    type=str,
+    help="Encoding to use to decode commands returned by the meter",
+    default="ascii",
+)
 @click.argument(
     "device-path",
     type=click.Path(exists=True, dir_okay=False, writable=True, allow_dash=False),
@@ -51,6 +58,7 @@ def main(
     text_reply_type: int,
     product_id: Optional[int],
     device_path: Optional[pathlib.Path],
+    encoding: str,
 ):
     if not product_id and not device_path:
         raise click.UsageError(
@@ -58,7 +66,7 @@ def main(
         )
 
     session = freestyle_hid.Session(
-        product_id, device_path, text_command_type, text_reply_type
+        product_id, device_path, text_command_type, text_reply_type, encoding=encoding
     )
 
     session.connect()
-- 
cgit v1.2.3