Allow omitted rule constraints to match any value (#101)

The definition of umodbus.server.route gives default values of None to the arguments, suggesting they can be omitted. However, if you actually provide None, it will fail later when evaluating DataRule.match.

This change makes it possible to omit any rule constraint to match on any value.

dev_requirements.txt

@@ -1,5 +1,6 @@
 -r requirements.txt
 
+mock==3.0.5;python_version<"3.3"
 pytest==5.3.1;python_version>="3.5"
 pytest==4.6.6;python_version<"3.5"
 pytest-cov==2.8.1

tests/unit/test_route.py

@@ -0,0 +1,36 @@
+import pytest
+
+from umodbus.route import DataRule
+
+
+endpoint = lambda slave_id, function_code, address: 0
+
+
+def test_basic_route():
+    rule = DataRule(endpoint, slave_ids=[1], function_codes=[1], addresses=[1])
+    assert rule.match(slave_id=1, function_code=1, address=1)
+    assert not rule.match(slave_id=0, function_code=1, address=1)
+    assert not rule.match(slave_id=1, function_code=0, address=1)
+    assert not rule.match(slave_id=1, function_code=1, address=0)
+
+
+def test_other_iterables():
+    # Other iterable types should work, not just lists
+    rule = DataRule(endpoint,
+                    slave_ids=set([1]), function_codes=[1], addresses=[1])
+    assert rule.match(slave_id=1, function_code=1, address=1)
+
+
+def test_wildcard_slave_id():
+    rule = DataRule(endpoint, slave_ids=None, function_codes=[1], addresses=[1])
+    assert rule.match(slave_id=1, function_code=1, address=1)
+
+
+def test_wildcard_function_code():
+    rule = DataRule(endpoint, slave_ids=[1], function_codes=None, addresses=[1])
+    assert rule.match(slave_id=1, function_code=1, address=1)
+
+
+def test_wildcard_address():
+    rule = DataRule(endpoint, slave_ids=[1], function_codes=[1], addresses=None)
+    assert rule.match(slave_id=1, function_code=1, address=1)

umodbus/route.py

@@ -20,9 +20,8 @@ def __init__(self, endpoint, slave_ids, function_codes, addresses):
         self.addresses = addresses
 
     def match(self, slave_id, function_code, address):
-        if slave_id in self.slave_ids and\
-            function_code in self.function_codes and \
-                address in self.addresses:
-                    return True
-
-        return False
+        # A constraint of None matches any value
+        matches = lambda values, v: values is None or v in values
+        return matches(self.slave_ids, slave_id) and \
+               matches(self.function_codes, function_code) and \
+               matches(self.addresses, address)

umodbus/server/__init__.py

@@ -19,9 +19,11 @@ def route(self, slave_ids=None, function_codes=None, addresses=None):
         def read_single_bit_values(slave_id, address):
             return random.choise([0, 1])
 
-    :param slave_ids: A list or set with slave id's.
-    :param function_codes: A list or set with function codes.
-    :param addresses: A list or set with addresses.
+    Any argument can be omitted to match any value.
+
+    :param slave_ids: A list (or iterable) of slave ids.
+    :param function_codes: A list (or iterable) of function codes.
+    :param addresses: A list (or iterable) of addresses.
     """
     def inner(f):
         self.route_map.add_rule(f, slave_ids, function_codes, addresses)