I am trying to implement an SPV client in python (for my own learning). I want to start by making a simple TCP connection to a full node, but I either cannot get a response to my version message, or to my verack message if the version message goes through. I have referenced this and this is the code that I am trying to run:

#Import dependencies import socket import time import random import struct import hashlib import binascii import ssl import socks # Binary encode the sub-version def create_sub_version(): sub_version = "/Satoshi:0.7.2/" return b'\x0F' + sub_version.encode() # Binary encode the network addresses def create_network_address(ip_address, port): network_address = struct.pack('>8s16sH', b'\x01', bytearray.fromhex("00000000000000000000ffff") + socket.inet_aton(ip_address), port) return(network_address) # Create the TCP request object def create_message(magic, command, payload): checksum = hashlib.sha256(hashlib.sha256(payload).digest()).digest()[0:4] return(struct.pack('L12sL4s', magic, command.encode(), len(payload), checksum) + payload) # Create the "version" request payload def create_payload_version(peer_ip_address): version = 60002 services = 1 timestamp = int(time.time()) addr_local = create_network_address("127.0.0.1", 8333) addr_peer = create_network_address(peer_ip_address, 8333) nonce = random.getrandbits(64) start_height = 645953 payload = struct.pack('<LQQ26s26sQ16sL', version, services, timestamp, addr_peer, addr_local, nonce, create_sub_version(), start_height) return(payload) # Create the "verack" request message def create_message_verack(): return bytearray.fromhex("f9beb4d976657261636b000000000000000000005df6e0e2") # Create the "getdata" request payload def create_payload_getdata(tx_id): count = 1 type = 1 hash = bytearray.fromhex(tx_id) payload = struct.pack('<bb32s', count, type, hash) return(payload) # Print request/response data def print_response(command, request_data, response_data): print("") print("Command: " + command) print("Request:") print(binascii.hexlify(request_data)) print("Response:") print(binascii.hexlify(response_data)) if __name__ == '__main__': # Set constants magic_value = 0xd9b4bef9 tx_id = "a13e7979d3607e187d2ce81ca9fdadfe967b2f3fc1109ce47d46cc09ebd41c50" peer_ip_address = socket.gethostbyname('bitcoin.aranguren.org') peer_tcp_port = 50002 buffer_size = 1024 # Create Request Objects version_payload = create_payload_version(peer_ip_address) version_message = create_message(magic_value, 'version', version_payload) verack_message = create_message_verack() getdata_payload = create_payload_getdata(tx_id) getdata_message = create_message(magic_value, 'getdata', getdata_payload) # Establish TCP Connection s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(10) ws = ssl.wrap_socket(s, ssl_version=ssl.PROTOCOL_TLSv1) ws.connect((peer_ip_address, peer_tcp_port)) # Send message "version" ws.send(version_message) response_data = ws.recv(buffer_size) print_response("version", version_message, response_data) # Send message "verack" ws.send(verack_message) response_data = ws.recv(buffer_size) print_response("verack", verack_message, response_data) # Send message "getdata" ws.send(getdata_message) response_data = ws.recv(buffer_size) print_response("getdata", getdata_message, response_data) # Close the TCP connection ws.close() 

The server I connect to in the code is among the only ones that would respond to the version message, returning b'7b226a736f6e727063223a2022322e30222c20226572726f72223a207b22636f6465223a202d33323730302c20226d657373616765223a20226d65737361676573206d75737420626520656e636f64656420696e205554462d38227d2c20226964223a206e756c6c7d0a'.

I also tried referencing: this stack exchange question and Ken Shirriff's github code, but none seem to work, either because I am using python3 or from other causes. I am a beginner in this, so if somebody could help me understand why I cannot get my messages across in the above code or has another implementation in python3, I would be grateful.