Its been a struggle to get SSLPeerName working in a python app. We got it working doing the below. Seems like a lot of hoops to jump thru Is there a cleaner, simpler way? Yes, I know we could use a Client Channel Definition Table. Is there a better way to do it with code ahead of the MQCONNX call is the question.

# Create a bytes string variable that can be used in C code, since peer name functionality relies on raw C code

cPeerName = ctypes.c_char_p(b'CN=mqcnhx99.thehartford.com')

# Get the pointer (as a string) for the physical location of this C/Python variable in memory (memory address) ie: "c_char_p(1829825702992)"

cPeerNamePointer = str(ctypes.pointer(cPeerName).contents)

# Extract the integer value that the pointer has for the memory address of the C/Python variable. This is stored between "(" and ")"

# ie: c_char_p(1829825702992) extracts to ==> 1829825702992

cPeerNamePointerInt = int(cPeerNamePointer[str(cPeerNamePointer).index('(') + 1 : str(cPeerNamePointer).index(')')])

# Set the pymqi peer name value to the pointer's integer value. The C code will use this pointer to get the value of cPeerName in the MQ libraries from memory

cd.SSLPeerNamePtr = cPeerNamePointerInt

# Set the peer name length to match the value of cPeerName. Since the value of cPeerName is in bytes, decode it back to the string value

cd.SSLPeerNameLength = len(str(cPeerName.value, encoding='utf-8'))

Hi Peter,

Looking at the way the PyMQI libraries implemented set_vs for MQCHARV structures, I copied that a little and came up with the setPeerName function shown below to add to my own ssl.py application. You need to import ctypes to use it, and I already had the pyStr function to get around the Python 2 v 3 string debacle - there's probably a better way to do that bit if you know which version of Python you're using, but it works for me so I've kinda stuck with it - keeps the rest of the code a little tidier and I think better in strings than bytes. Hopefully this makes sense but if it helps I can send you the whole sample application.

def pyStr(data):
  if sys.version_info.major < 3:
    return str(data)
  else:
    return bytes(data, 'utf-8')

def setPeerName(data):
  c_value = ctypes.create_string_buffer(data)
  c_value_p = ctypes.cast(c_value, ctypes.c_void_p).value
  cd.SSLPeerNamePtr = c_value_p
  cd.SSLPeerNameLength = len(data)

then later in my program I called:-

if (args.peername):
setPeerName(pyStr(args.peername))

Cheers,
Morag

Its been a struggle to get SSLPeerName working in a python app. We got it working doing the below. Seems like a lot of hoops to jump thru Is there a cleaner, simpler way? Yes, I know we could use a Client Channel Definition Table. Is there a better way to do it with code ahead of the MQCONNX call is the question.

# Create a bytes string variable that can be used in C code, since peer name functionality relies on raw C code

cPeerName = ctypes.c_char_p(b'CN=mqcnhx99.thehartford.com')

# Get the pointer (as a string) for the physical location of this C/Python variable in memory (memory address) ie: "c_char_p(1829825702992)"

cPeerNamePointer = str(ctypes.pointer(cPeerName).contents)

# Extract the integer value that the pointer has for the memory address of the C/Python variable. This is stored between "(" and ")"

# ie: c_char_p(1829825702992) extracts to ==> 1829825702992

cPeerNamePointerInt = int(cPeerNamePointer[str(cPeerNamePointer).index('(') + 1 : str(cPeerNamePointer).index(')')])

# Set the pymqi peer name value to the pointer's integer value. The C code will use this pointer to get the value of cPeerName in the MQ libraries from memory

cd.SSLPeerNamePtr = cPeerNamePointerInt

# Set the peer name length to match the value of cPeerName. Since the value of cPeerName is in bytes, decode it back to the string value

cd.SSLPeerNameLength = len(str(cPeerName.value, encoding='utf-8'))