Sort out some problems with hidapi USB modules

Signed-off-by: Jim Easterbrook <jim@jim-easterbrook.me.uk>

src/pywws/__init__.py

@@ -1,3 +1,3 @@
-__version__ = '21.4.0'
-_release = '1690'
-_commit = 'dbede59'
+__version__ = '21.11.0'
+_release = '1691'
+_commit = '87168bf'

src/pywws/device_ctypes_hidapi.py

@@ -141,7 +141,7 @@ def write_data(self, buf):
         :rtype: bool
 
         """
-        data = ''.join(map(chr, buf))
+        data = bytes(buf)
         size = len(data)
         if hidapi.hid_write(self.device, ctypes.c_char_p(data), size) != size:
             raise IOError(

src/pywws/device_cython_hidapi.py

@@ -51,6 +51,8 @@
 
 __docformat__ = "restructuredtext en"
 
+from contextlib import contextmanager
+
 import hid
 
 class USBDevice(object):
@@ -69,8 +71,18 @@ class USBDevice(object):
     def __init__(self, idVendor, idProduct):
         if not hid.enumerate(idVendor, idProduct):
             raise IOError("No weather station connected")
+        self.idVendor = idVendor
+        self.idProduct = idProduct
         self.hid = hid.device(idVendor, idProduct)
 
+    @contextmanager
+    def open(self):
+        try:
+            self.hid.open(self.idVendor, self.idProduct)
+            yield
+        finally:
+            self.hid.close()
+
     def read_data(self, size):
         """Receive data from the device.
 
@@ -87,14 +99,15 @@ def read_data(self, size):
 
         """
         result = list()
-        while size > 0:
-            count = min(size, 8)
-            buf = self.hid.read(count)
-            if len(buf) < count:
-                raise IOError(
-                    'pywws.device_cython_hidapi.USBDevice.read_data failed')
-            result += buf
-            size -= count
+        with self.open():
+            while size > 0:
+                count = min(size, 8)
+                buf = self.hid.read(count)
+                if len(buf) < count:
+                    raise IOError(
+                        'pywws.device_cython_hidapi.USBDevice.read_data failed')
+                result += buf
+                size -= count
         return result
 
     def write_data(self, buf):
@@ -109,7 +122,8 @@ def write_data(self, buf):
         :rtype: bool
 
         """
-        if self.hid.write(buf) != len(buf):
-            raise IOError(
-                'pywws.device_cython_hidapi.USBDevice.write_data failed')
+        with self.open():
+            if self.hid.write(buf) != len(buf):
+                raise IOError(
+                    'pywws.device_cython_hidapi.USBDevice.write_data failed')
         return True