Sending information with bluetooth on Raspberry Pi (Python)

bluetooth-raspberry-pi-communication.py

# Uses Bluez for Linux
#
# sudo apt-get install bluez python-bluez
# 
# Taken from: https://people.csail.mit.edu/albert/bluez-intro/x232.html
# Taken from: https://people.csail.mit.edu/albert/bluez-intro/c212.html

import bluetooth

def receiveMessages():
  server_sock=bluetooth.BluetoothSocket( bluetooth.RFCOMM )
  
  port = 1
  server_sock.bind(("",port))
  server_sock.listen(1)
  
  client_sock,address = server_sock.accept()
  print "Accepted connection from " + str(address)
  
  data = client_sock.recv(1024)
  print "received [%s]" % data
  
  client_sock.close()
  server_sock.close()
  
def sendMessageTo(targetBluetoothMacAddress):
  port = 1
  sock=bluetooth.BluetoothSocket( bluetooth.RFCOMM )
  sock.connect((targetBluetoothMacAddress, port))
  sock.send("hello!!")
  sock.close()
  
def lookUpNearbyBluetoothDevices():
  nearby_devices = bluetooth.discover_devices()
  for bdaddr in nearby_devices:
    print str(bluetooth.lookup_name( bdaddr )) + " [" + str(bdaddr) + "]"
    
    
lookUpNearbyBluetoothDevices()

When I run this code on my Pi 3B+ I get an empty list [] from bluetooth.discover_devices(). Running the graphic interface or sudo bluetoothctl from the command line I see a whole bunch of devices, including my SiliconLabs BGX13P and my Sensirion Humidity and temperature sensor that I am trying to use as guinea pigs. Any suggestions?

What guinea pigs? Are you torturing some pigs?

I got an issue with this program:
Detecting bluetooth devices works just fine, I can detect my phone and my other bluetooth devices, but when sending messages to my phone a "connection refused" error raises (but that's probably because it's got some built-in protection against scary Linux devices). So that's when I thought 'hey, what if I try it using my pi zero w?'

so I used two pi's for my tryout of this program:

• a headless pi zero w automatically loads the script (using crontab), detects bluetooth devices using lookUpNearbyBluetoothDevices() and sends a message to all of them (by using sendMessageTo in a try function)
• a pi 4 B connected to a monitor is running the function receiveMessages(), but doesn't receive anything at all

And that's the problem! They're both pi's , and I suppose sending messages between two pi's using this program would work.
Can anyone help me out please?

PS: I like your program, even when only a small part of it works that's a lot better than most internet pieces of code.