Finished corrections to Variable DID size implementation.

Author: pylessard

test/client/test_read_data_by_identifier.py

@@ -26,7 +26,7 @@ def decode(self, did_payload):
         return did_payload
 
     def __len__(self):
-        return self.ReadAllRemainingData
+        raise self.ReadAllRemainingData
 
 class CodecWithNoLength(DidCodec):
 
@@ -162,7 +162,7 @@ def _test_rdbi_variable_size_did(self):
 
     # DID 5 read all the data up to the end. Makes no sense to read another DID after that.
     def test_rdbi_variable_size_did_not_last(self):
-        pass  
+        pass
 
     def _test_rdbi_variable_size_did_not_last(self):
         with self.assertRaises(ValueError):
@@ -257,5 +257,5 @@ def test_no_length(self):
         pass
 
     def _test_no_length(self):
-        with self.assertRaises(ConfigError):
+        with self.assertRaises(NotImplementedError):
             self.udsclient.read_data_by_identifier(didlist=[6]) 

udsoncan/__init__.py

@@ -40,7 +40,7 @@ class DidCodec:
     :type packstr: string
     """
 
-    class ReadAllRemainingData:
+    class ReadAllRemainingData(Exception):
         pass
 
     def __init__(self, packstr=None):

udsoncan/services/ReadDataByIdentifier.py

@@ -45,10 +45,28 @@ def make_request(cls, didlist, didconfig):
         :raises ConfigError: If didlist contains a DID not defined in didconfig
         """		
         from udsoncan import Request
+        from udsoncan import DidCodec
+
         didlist = cls.validate_didlist_input(didlist)
 
         req = Request(cls)
         ServiceHelper.check_did_config(didlist, didconfig)
+
+        did_reading_all_data = None
+        for did in didlist:
+            if did not in didconfig:    # Already checked in check_did_config. Paranoid check
+                raise ConfigError(key=did, msg='Actual data identifier configuration contains no definition for data identifier 0x%04x' % did)
+                
+            codec = DidCodec.from_config(didconfig[did])
+            try:
+                length = len(codec)
+                if did_reading_all_data is not None:
+                    raise ValueError('Did 0x%04X is configured to read the rest of the payload (__len__ raisong ReadAllRemainingData), but a subsequent DID is requested (0x%04x)' % (did_reading_all_data, did))
+            except DidCodec.ReadAllRemainingData:
+                if did_reading_all_data is not None:
+                    raise ValueError('It is impossible to read 2 DIDs configured to read the rest of the payload (__len__ raising ReadAllRemainingData). Dids are : 0x%04X and 0x%04X' % (did_reading_all_data, did))
+                did_reading_all_data = did
+
         req.data = struct.pack('>'+'H'*len(didlist), *didlist) #Encode list of DID
 
         return req
@@ -106,12 +124,8 @@ def interpret_response(cls, response, didlist, didconfig, tolerate_zero_padding=
 
             try:
                 payload_size = len(codec)
-            except NotImplementedError as nie:
-                if len(didlist) > 1:
-                    raise nie
-                else:
-                    # we assume the remaining response data corresponds to only one DID, thus read all of it
-                    payload_size = len(response.data) - offset
+            except DidCodec.ReadAllRemainingData:
+                payload_size = len(response.data) - offset
 
             if len(response.data) < offset+payload_size:
                 raise InvalidResponseException(response, "Value for data identifier 0x%04x was incomplete according to definition in configuration" % did)