Common on PCF parser dealing with CFSTs that are not multiples of 4. See #10

Author: ibmmqmet

CHANGELOG.md

@@ -7,6 +7,7 @@ Newest updates are at the top of this file.
   - get_header() function to extract structure (#4)
   - get_embedded_md() function
 * Added MQMDE class for if you want to parse MQXQH messages
+* Add comments about PCF parser leaving padding on strings that are not rounded to 4 bytes (#10)
 
 ## 2025 Oct 16 - V2.0.0
 * First production release, based on MQ 9.4.4

code/examples/dis_queues.py

@@ -80,7 +80,13 @@
             try:
                 queue_name = queue_info[mq.CMQC.MQCA_Q_NAME]
                 depth = queue_info[mq.CMQC.MQIA_CURRENT_Q_DEPTH]
-                print(f'Found queue {queue_name} depth: {depth}')
+                lputtime = mq.to_string(queue_info[mq.CMQCFC.MQCACF_LAST_PUT_TIME])
+                lputdate = mq.to_string(queue_info[mq.CMQCFC.MQCACF_LAST_PUT_DATE])
+                if lputdate != "":
+                    lput = lputdate + ":" + lputtime
+                else:
+                    lput = "N/A"
+                print(f'Found queue {queue_name} depth: {depth} lastPut: {lput}')
             except KeyError as e:
                 print('Failure to decode msg because ', e)
 

code/ibmmq/mqadmin.py

@@ -397,7 +397,7 @@ def __init__(self, name=None,
         # as there would be no time at all to wait for the response. But we'll allow you to
         # find that for yourself.
         if response_wait_interval < 0:
-            response_wait_interval = 60 * 60 * 1000  
+            response_wait_interval = 60 * 60 * 1000
         self.__response_wait_interval = response_wait_interval
 
         if model_queue_name and reply_queue_name:
@@ -542,7 +542,10 @@ def unpack(message: bytes) -> tuple[dict, CFH]:
                 if parameter.StringLength > 1:
                     parameter = CFST(StringLength=parameter.StringLength)
                     parameter.unpack(message[cursor:cursor + parameter.StrucLength])
-                value = parameter.String
+                # The parameter.String contents might include padding bytes that round up the length.
+                # Ideally we'd truncate, but this was behaviour in the original library so I'm reluctant
+                # to fix it.
+                value = parameter.String   # [:parameter.StringLength] - would truncate
             elif parameter_type == CMQCFC.MQCFT_STRING_LIST:
                 parameter = CFSL()
                 parameter.unpack(message[cursor:cursor + CMQCFC.MQCFSL_STRUC_LENGTH_FIXED])
@@ -551,6 +554,8 @@ def unpack(message: bytes) -> tuple[dict, CFH]:
                                      Count=parameter.Count,
                                      StrucLength=parameter.StrucLength)
                     parameter.unpack(message[cursor:cursor + parameter.StrucLength])
+                # CFSL doesn't have the same padding issue as CFST as all supported
+                # attributes are multiples of 4.
                 value = parameter.Strings
             elif parameter_type == CMQCFC.MQCFT_INTEGER:
                 parameter = CFIN()

code/ibmmq/mqopts.py

@@ -254,21 +254,19 @@ def _remove(self, key: str) -> None:
         This removes both the attribute and knowledge about how it is formatted
         """
         # Have to convert tuples into a list so it can be modified
-        l = list(self.__list)
+        tmp_list = list(self.__list)
 
-        for item in l:
+        for item in tmp_list:
             if item[0] == key:
-                l.remove(item)
+                tmp_list.remove(item)
                 try:
-                     delattr(self,key)
+                    delattr(self, key)
                 except AttributeError:
                     pass
                 break
 
         # And then convert back to the tuple format
-        self.__list = tuple(l)
-
-        return
+        self.__list = tuple(tmp_list)
 
     def __str__(self) -> str:
         rv = ''

code/ibmmq/mqpcf.py

@@ -229,6 +229,8 @@ def __init__(self, **kw: Dict[str, Any]):
 class CFST(MQOpts):
     """ Construct an MQCFST (PCF String) structure with default values as per MQI.
     The default values may be overridden by the optional keyword arguments 'kw'.
+    Note that the "String" may include the padding bytes, so you have to use the
+    StringLength field to extract the real value.
     """
 
     def __init__(self, **kw: Dict[str, Any]):

setup.py

@@ -17,7 +17,7 @@
 # The version should correspond to PEP440 and gets normalised if
 # not in the right format. VRM can be followed with a|b|rc with a further numeric
 # to indicate alpha/beta/release-candidate versions.
-VERSION = '2.0.0'
+VERSION = '2.0.1'
 
 # If the MQ SDK is in a non-default location, set MQ_FILE_PATH environment variable.
 custom_path = os.environ.get('MQ_FILE_PATH', None)