Bluetoothctl wrapper in Python

bluetoothctl.py

# ReachView code is placed under the GPL license.
# Written by Egor Fedorov (egor.fedorov@emlid.com)
# Copyright (c) 2015, Emlid Limited
# All rights reserved.

# If you are interested in using ReachView code as a part of a
# closed source project, please contact Emlid Limited (info@emlid.com).

# This file is part of ReachView.

# ReachView is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# ReachView is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with ReachView.  If not, see <http://www.gnu.org/licenses/>.

import time
import pexpect
import subprocess
import sys

class BluetoothctlError(Exception):
    """This exception is raised, when bluetoothctl fails to start."""
    pass


class Bluetoothctl:
    """A wrapper for bluetoothctl utility."""

    def __init__(self):
        out = subprocess.check_output("rfkill unblock bluetooth", shell = True)
        self.child = pexpect.spawn("bluetoothctl", echo = False)

    def get_output(self, command, pause = 0):
        """Run a command in bluetoothctl prompt, return output as a list of lines."""
        self.child.send(command + "\n")
        time.sleep(pause)
        start_failed = self.child.expect(["bluetooth", pexpect.EOF])

        if start_failed:
            raise BluetoothctlError("Bluetoothctl failed after running " + command)

        return self.child.before.split("\r\n")

    def start_scan(self):
        """Start bluetooth scanning process."""
        try:
            out = self.get_output("scan on")
        except BluetoothctlError, e:
            print(e)
            return None

    def make_discoverable(self):
        """Make device discoverable."""
        try:
            out = self.get_output("discoverable on")
        except BluetoothctlError, e:
            print(e)
            return None

    def parse_device_info(self, info_string):
        """Parse a string corresponding to a device."""
        device = {}
        block_list = ["[\x1b[0;", "removed"]
        string_valid = not any(keyword in info_string for keyword in block_list)

        if string_valid:
            try:
                device_position = info_string.index("Device")
            except ValueError:
                pass
            else:
                if device_position > -1:
                    attribute_list = info_string[device_position:].split(" ", 2)
                    device = {
                        "mac_address": attribute_list[1],
                        "name": attribute_list[2]
                    }

        return device

    def get_available_devices(self):
        """Return a list of tuples of paired and discoverable devices."""
        try:
            out = self.get_output("devices")
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            available_devices = []
            for line in out:
                device = self.parse_device_info(line)
                if device:
                    available_devices.append(device)

            return available_devices

    def get_paired_devices(self):
        """Return a list of tuples of paired devices."""
        try:
            out = self.get_output("paired-devices")
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            paired_devices = []
            for line in out:
                device = self.parse_device_info(line)
                if device:
                    paired_devices.append(device)

            return paired_devices

    def get_discoverable_devices(self):
        """Filter paired devices out of available."""
        available = self.get_available_devices()
        paired = self.get_paired_devices()

        return [d for d in available if d not in paired]

    def get_device_info(self, mac_address):
        """Get device info by mac address."""
        try:
            out = self.get_output("info " + mac_address)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            return out

    def pair(self, mac_address):
        """Try to pair with a device by mac address."""
        try:
            out = self.get_output("pair " + mac_address, 4)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            res = self.child.expect(["Failed to pair", "Pairing successful", pexpect.EOF])
            success = True if res == 1 else False
            return success

    def remove(self, mac_address):
        """Remove paired device by mac address, return success of the operation."""
        try:
            out = self.get_output("remove " + mac_address, 3)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            res = self.child.expect(["not available", "Device has been removed", pexpect.EOF])
            success = True if res == 1 else False
            return success

    def connect(self, mac_address):
        """Try to connect to a device by mac address."""
        try:
            out = self.get_output("connect " + mac_address, 2)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            res = self.child.expect(["Failed to connect", "Connection successful", pexpect.EOF])
            success = True if res == 1 else False
            return success

    def disconnect(self, mac_address):
        """Try to disconnect to a device by mac address."""
        try:
            out = self.get_output("disconnect " + mac_address, 2)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            res = self.child.expect(["Failed to disconnect", "Successful disconnected", pexpect.EOF])
            success = True if res == 1 else False
            return success


if __name__ == "__main__":

    print("Init bluetooth...")
    bl = Bluetoothctl()
    print("Ready!")
    bl.start_scan()
    print("Scanning for 10 seconds...")
    for i in range(0, 10):
        print(i)
        time.sleep(1)

    print(bl.get_discoverable_devices())

Why do you have to wait after sending a pair or connect request to bluetoothctl? It returns instantly, as far as I can see, and pexpect.expect() will wait for the result anyway.

I'm getting this error.... how can i resolve it...

Traceback (most recent call last):
File "/home/pi/Desktop/bluetoothctl.py", line 190, in
bl = Bluetoothctl()
File "/home/pi/Desktop/bluetoothctl.py", line 38, in init
out = subprocess.check_output("rfkill unblock bluetooth", shell = True)
File "/usr/lib/python2.7/subprocess.py", line 573, in check_output
raise CalledProcessError(retcode, cmd, output=output)
CalledProcessError: Command 'rfkill unblock bluetooth' returned non-zero exit status 1

... thank you, it's very helpful :)

I appreciate for sharing :).

I am unable to figure out to pair end device which has pin-code and no GUI. If you can give any suggestion it would be helpful.

For error: CalledProcessError: Command 'rfkill unblock bluetooth' returned non-zero exit status 1

change line 42:
out = subprocess.check_output("PATH=/usr/sbin:$PATH; rfkill unblock bluetooth", shell = True)

@taufeeq25 typically such a device has a hardcoded default pin, e.g. 0000, 1234 etc. then once paired some devices accept a command to set a custom one, if desired.

How to stop the scan. I copied the function of start scan and modified it for the "scan off" command but it does not work and throws an exception.

def stop_scan(self):
"""Stop bluetooth scanning process."""
try:
out = self.get_output("scan off")
except Exception, e:
print(e)
return None

Hello thanks for the code,
but when i run agent on , there is a pairing code that will be sent to the phone and then how can i confrim the pairing code from the raspberry pi ?
any suggestions would be appreciated !!

for python 3.6 https://gist.github.com/castis/0b7a162995d0b465ba9c84728e60ec01

Hi @egor,
Is there any chance you could enable RSSI as JSON field as well? so it will be like:
{"name":"Example","mac_address":"00:00:00:00:00","RSSI":"100"} ? that would help for distance determination.
Thanks in Advance.

Thanks alot. It saves my time.