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I'm using Python to communicate data over a TCP socket between a server and client application. I need to send a 4 bytes which represent a data sample. The initial sample is an 32-bit unsigned integer. How can I send those 4 bytes of raw data through the socket?

I want to send the data: 0x12345678 and 0xFEDCBA98 The raw data sent over the socket should be exactly that if I read it on wireshark/tcpdump/etc. I don't want each value in the 8 hex numbers to be represented as an ascii character, I want the raw data to remain intact.

Thank you

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2 Answers 2

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The main method to send binary data in Python is using the struct module.

For example, packing 3 4-byte unsigned integers is done like this

In [3]: struct.pack("III", 3, 4, 5)
Out[3]: '\x03\x00\x00\x00\x04\x00\x00\x00\x05\x00\x00\x00'

Note to keep the endianess correct, using "<", ">", and so on.

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Hey, thank you for your response, As far as I can tell, I think that's what I wanted!
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you could use bytes(). Thats what I use to send strings over a network but you can use it for ints as well. Its usage is bytes([3])

Edit: bytes converts an int (3) to bytes. a string of bytes is represented as b'\x03'. so like your byte string: 0x12345678 would be b'\x12345678'

check the docs for more info: https://docs.python.org/3.1/library/functions.html#bytes

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I'm not quite sure this is what I want, but I appreciate your response. Thanks

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