5 files changed, 85 insertions, 49 deletions

diff --git a/glucometerutils/drivers/fsoptium.py b/glucometerutils/drivers/fsoptium.py
index a380c96..d1b5f24 100644
--- a/glucometerutils/drivers/fsoptium.py
+++ b/glucometerutils/drivers/fsoptium.py
@@ -15,10 +15,9 @@ import datetime
 import logging
 import re
 
-import serial
-
 from glucometerutils import common
 from glucometerutils import exceptions
+from glucomterutils.support import serial
 
 
 _CLOCK_RE = re.compile(
@@ -77,16 +76,9 @@ def _parse_clock(datestr):
   return datetime.datetime(year, month, day, hour, minute, second)
 
 
-class Device(object):
-  def __init__(self, device):
-    if not device:
-      logging.info('No --device parameter provided, looking for default cable.')
-      device = 'hwgrep://1a61:3420'
-
-    self.serial_ = serial.serial_for_url(
-      device, baudrate=19200, bytesize=serial.EIGHTBITS,
-      parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
-      timeout=1, xonxoff=True, rtscts=False, dsrdtr=False, writeTimeout=None)
+class Device(serial.SerialDevice):
+  BAUDRATE = 19200
+  DEFAULT_CABLE_ID = '1a61:3420'
 
   def _send_command(self, command):
     cmd_bytes = bytes('$%s\r\n' % command, 'ascii')
diff --git a/glucometerutils/drivers/otultra2.py b/glucometerutils/drivers/otultra2.py
index 28a4771..8e33ea5 100644
--- a/glucometerutils/drivers/otultra2.py
+++ b/glucometerutils/drivers/otultra2.py
@@ -10,11 +10,10 @@ import datetime
 import logging
 import re
 
-import serial
-
 from glucometerutils import common
 from glucometerutils import exceptions
 from glucometerutils.support import lifescan
+from glucometerutils.support import serial
 
 # The following two hashes are taken directly from LifeScan's documentation
 _MEAL_CODES = {
@@ -123,16 +122,9 @@ def _parse_datetime(response):
   return datetime.datetime(2000 + year, month, day, hour, minute, second)
 
 
-class Device(object):
-  def __init__(self, device):
-    if not device:
-      logging.info('No --device parameter provided, looking for default cable.')
-      device = 'hwgrep://067b:2303'
-
-    self.serial_ = serial.serial_for_url(
-      device, baudrate=9600, bytesize=serial.EIGHTBITS,
-      parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
-      timeout=1, xonxoff=False, rtscts=False, dsrdtr=False, writeTimeout=None)
+class Device(serial.SerialDevice):
+  BAUDRATE = 9600
+  DEFAULT_CABLE_ID = '067b:2303'  # Generic PL2303 cable.
 
   def connect(self):
     return
diff --git a/glucometerutils/drivers/otultraeasy.py b/glucometerutils/drivers/otultraeasy.py
index 2976b9e..31b719f 100644
--- a/glucometerutils/drivers/otultraeasy.py
+++ b/glucometerutils/drivers/otultraeasy.py
@@ -13,11 +13,10 @@ import re
 import struct
 import time
 
-import serial
-
 from glucometerutils import common
 from glucometerutils import exceptions
 from glucometerutils.support import lifescan
+from glucometerutils.support import serial
 
 _STX = 0x02
 _ETX = 0x03
@@ -176,16 +175,12 @@ class _Packet(object):
     return self.cmd[_IDX_DATA:_IDX_ETX]
 
 
-class Device(object):
+class Device(serial.SerialDevice):
+  BAUDRATE = 9600
+  DEFAULT_CABLE_ID = '067b:2303'  # Generic PL2303 cable.
+
   def __init__(self, device):
-    if not device:
-      logging.info('No --device parameter provided, looking for default cable.')
-      device = 'hwgrep://067b:2303'
-
-    self.serial_ = serial.serial_for_url(
-      device, baudrate=9600, bytesize=serial.EIGHTBITS,
-      parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
-      timeout=1, xonxoff=False, rtscts=False, dsrdtr=False, writeTimeout=None)
+    super(Device, self).__init__(device)
 
     self.sent_counter_ = False
     self.expect_receive_ = False
diff --git a/glucometerutils/drivers/sdcodefree.py b/glucometerutils/drivers/sdcodefree.py
index 0cd0b28..9aeb653 100644
--- a/glucometerutils/drivers/sdcodefree.py
+++ b/glucometerutils/drivers/sdcodefree.py
@@ -15,10 +15,9 @@ import operator
 import struct
 import time
 
-import serial
-
 from glucometerutils import common
 from glucometerutils import exceptions
+from glucometerutils.support import serial
 
 _STX = 0x53    # Not really 'STX'
 _ETX = 0xAA    # Not really 'ETX'
@@ -64,18 +63,10 @@ def parse_reading(msgdata):
 def xor_checksum(msg):
     return functools.reduce(operator.xor, msg)
 
-class Device(object):
-    def __init__(self, device):
-        if not device:
-            logging.info(
-                'No --device parameter provided, looking for default cable.')
-            device = 'hwgrep://10c4:ea60'
-
-        self.serial_ = serial.serial_for_url(
-            device, baudrate=38400, bytesize=serial.EIGHTBITS,
-            parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
-            timeout=300, xonxoff=False, rtscts=False, dsrdtr=False,
-            writeTimeout=None)
+class Device(serial.SerialDevice):
+    BAUDRATE = 38400
+    DEFAULT_CABLE_ID = '10c4:ea60'  # Generic cable.
+    TIMEOUT = 300  # We need to wait for data from the device.
 
     def read_packet(self):
         preamble = self.serial_.read(3)
diff --git a/glucometerutils/support/serial.py b/glucometerutils/support/serial.py
new file mode 100644
index 0000000..84bae87
--- /dev/null
+++ b/glucometerutils/support/serial.py
@@ -0,0 +1,66 @@
+"""Common routines and base driver class for serial-based meters.
+"""
+
+__author__ = 'Diego Elio Pettenò'
+__email__ = 'flameeyes@flameeyes.eu'
+__copyright__ = 'Copyright © 2017, Diego Elio Pettenò'
+__license__ = 'MIT'
+
+import logging
+
+import serial
+
+from glucometerutils import exceptions
+
+
+class SerialDevice(object):
+    """A Serial-connected glucometer driver base.
+
+    This class does not implement an actual driver by itself, but provides an
+    easier access to the boilerplate code required for pyserial.
+
+    This helper assumes that communication happens on a standard 8n1
+    configuration, with variable baudrate and no hardware flow control.
+
+    The actual drivers should set the following parameters:
+
+      BAUDRATE: (int) the speed the serial port should be opened at.
+      DEFAULT_CABLE_ID: (string) USB Vendor/Product ID pair, in format
+        abcd:abcd, of the default cable for the meter, in case the user
+        didn't pass an explicit device driver.
+
+    Optional parameters available:
+
+      TIMEOUT: (float, default: 1) the read timeout in seconds as defined by
+        pyserial.
+
+    After initialization, the following attributes can be used by the driver:
+      serial_: (serial.Serial) the open Serial object.
+
+    """
+
+    BAUDRATE = None
+    DEFAULT_CABLE_ID = None
+
+    TIMEOUT = 1
+
+    def __init__(self, device):
+        assert self.BAUDRATE is not None
+
+        if not device and self.DEFAULT_CABLE_ID:
+            logging.info(
+                'No --device parameter provided, looking for default cable.')
+            device = 'hwgrep://' + self.DEFAULT_CABLE_ID
+
+        if not device:
+            raise exceptions.CommandLineError(
+                'No --device parameter provided, and no default cable known.')
+
+        self.serial_ = serial.serial_for_url(
+            device,
+            baudrate=self.BAUDRATE,
+            timeout=self.TIMEOUT,
+            writeTimeout=None,
+            bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE,
+            stopbits=serial.STOPBITS_ONE,
+            xonxoff=True, rtscts=False, dsrdtr=False)