default settings on the IO class

allow to define default settings on the IO class:
- a default 'port' may be given for tcp
- defaults like 'baudrate' or 'parity' might be given
  for serial connections

this avoids explicit settings in the config file in case
the settings can not be changed or have a typical value
other than the defaults in serial.Serial

Change-Id: I990f47d63e785f8cc48c4af197944a8eebe91fb4
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/30555
Reviewed-by: Georg Brandl <g.brandl@fz-juelich.de>
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

doc/source/reference.rst

@@ -102,6 +102,7 @@ Communication
 
 .. autoclass:: frappy.io.IOBase
     :show-inheritance:
+    :members: default_settings
 
 .. autoclass:: frappy.io.StringIO
     :show-inheritance:

frappy/io.py

@@ -112,6 +112,12 @@ class IOBase(Communicator):
     wait_before = Parameter('wait time before sending', datatype=FloatRange(), default=0)
     is_connected = Parameter('connection state', datatype=BoolType(), readonly=False, default=False)
     pollinterval = Parameter('reconnect interval', datatype=FloatRange(0), readonly=False, default=10)
+    #: a dict of default settings for a device, e.g. for a LakeShore 336:
+    #:
+    #: ``default_settings = {'port': 7777, 'baudrate': 57600, 'parity': 'O', 'bytesize': 7}``
+    #:
+    #: port is used in case of tcp, the others for serial over USB
+    default_settings = {}
 
     _reconnectCallbacks = None
     _conn = None
@@ -243,7 +249,7 @@ class StringIO(IOBase):
     def connectStart(self):
         if not self.is_connected:
             uri = self.uri
-            self._conn = AsynConn(uri, self._eol_read)
+            self._conn = AsynConn(uri, self._eol_read, default_settings=self.default_settings)
             self.is_connected = True
             for command, regexp in self.identification:
                 reply = self.communicate(command)
@@ -354,7 +360,7 @@ class BytesIO(IOBase):
     def connectStart(self):
         if not self.is_connected:
             uri = self.uri
-            self._conn = AsynConn(uri, b'')
+            self._conn = AsynConn(uri, b'', default_settings=self.default_settings)
             self.is_connected = True
             for request, expected in self.identification:
                 replylen, replypat = make_regexp(expected)

frappy/lib/asynconn.py

@@ -32,6 +32,7 @@ import ast
 import select
 import socket
 import time
+import re
 
 from frappy.errors import CommunicationFailedError, ConfigError
 from frappy.lib import closeSocket, parseHostPort, tcpSocket
@@ -51,15 +52,14 @@ class AsynConn:
     scheme = None
     SCHEME_MAP = {}
     connection = None  # is not None, if connected
-    defaultport = None
 
-    def __new__(cls, uri, end_of_line=b'\n'):
+    def __new__(cls, uri, end_of_line=b'\n', default_settings=None):
         scheme = uri.split('://')[0]
         iocls = cls.SCHEME_MAP.get(scheme, None)
         if not iocls:
             # try tcp, if scheme not given
             try:
-                host_port = parseHostPort(uri, cls.defaultport)
+                host_port = parseHostPort(uri, None)
             except (ValueError, TypeError, AssertionError):
                 if 'COM' in uri:
                     raise ValueError("the correct uri for a COM port is: "
@@ -72,8 +72,9 @@ class AsynConn:
             uri = 'tcp://%s:%d' % host_port
         return object.__new__(iocls)
 
-    def __init__(self, uri, end_of_line=b'\n'):
+    def __init__(self, uri, end_of_line=b'\n', default_settings=None):
         self.end_of_line = end_of_line
+        self.default_settings = default_settings or {}
         self._rxbuffer = b''
 
     def __del__(self):
@@ -172,7 +173,7 @@ class AsynTcp(AsynConn):
             # should be the case always
             uri = uri[6:]
         try:
-            self.connection = tcpSocket(uri, self.defaultport, self.timeout)
+            self.connection = tcpSocket(uri, self.default_settings.get('port'), self.timeout)
         except (ConnectionRefusedError, socket.gaierror, socket.timeout) as e:
             # indicate that retrying might make sense
             raise CommunicationFailedError(str(e)) from None
@@ -218,7 +219,7 @@ class AsynSerial(AsynConn):
 
     uri syntax::
 
-      serial://<serial device>?[<option>=<value>[+<option>=<value> ...]]
+      serial://<serial device>?[<option>=<value>[&<option>=<value> ...]]
 
       options (defaults, other examples):
 
@@ -231,7 +232,9 @@ class AsynSerial(AsynConn):
       and others (see documentation of serial.Serial)
     """
     scheme = 'serial'
-    PARITY_NAMES = {name[0]: name for name in ['NONE', 'ODD', 'EVEN', 'MASK', 'SPACE']}
+    PARITY_NAMES = {name[0]: name for name in ['NONE', 'ODD', 'EVEN', 'MARK', 'SPACE']}
+    ARG_SEP = re.compile('[+&]')  # allow + or & as options separator in uri
+    SETTINGS = set(Serial(None).get_settings())  # keys of valid Serial settings
 
     def __init__(self, uri, *args, **kwargs):
         if Serial is None:
@@ -243,19 +246,19 @@ class AsynSerial(AsynConn):
             uri = uri[9:]
         uri = uri.split('?', 1)
         dev = uri[0]
-        try:
+        options = {k: v for k, v in self.default_settings.items() if k in self.SETTINGS}
-            options = dict((kv.split('=') for kv in uri[1].split('+')))
+        if len(uri) > 1:
-        except IndexError:  # no uri[1], no options
+            for kv in self.ARG_SEP.split(uri[1]):
-            options = {}
+                try:
-        except ValueError as e:
+                    key, value = kv.split('=')
-            raise ConfigError('illegal serial options') from e
+                except TypeError:
-        parity = options.pop('parity', None)  # only parity is to be treated as text
+                    raise ConfigError('%r must be <key>=<value>' % kv) from None
-        for k, v in options.items():
+                if key == 'parity':
-            try:
+                    options[key] = value
-                options[k] = ast.literal_eval(v.title())  # title(): turn false/true into False/True
+                else:
-            except ValueError:
+                    options[key] = ast.literal_eval(value.title())  # title(): turn false/true into False/True
-                pass
+        parity = options.get('parity')
-        if parity is not None:
+        if parity:
             name = parity.upper()
             fullname = self.PARITY_NAMES[name[0]]
             if not fullname.startswith(name):

frappy_demo/lakeshore.py

@@ -32,6 +32,7 @@ class LakeshoreIO(StringIO):
     # Lakeshore commands (see manual)
     # '*IDN?' is sent on connect, and the reply is checked to match the regexp 'LSCI,.*'
     identification = [('*IDN?', 'LSCI,.*')]
+    default_settings = {'port': 7777, 'baudrate': 57600, 'parity': 'O', 'bytesize': 7}
 
 
 class TemperatureSensor(HasIO, Readable):