Bluetoothctl wrapper in Python

bluetoothctl.py

# ReachView code is placed under the GPL license.
# Written by Egor Fedorov ([email protected])
# 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 ([email protected]).

# 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
import re

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 get_connectable_devices(self):
        """Get a  list of connectable devices.
        Must install 'sudo apt-get install bluez blueztools' to use this"""
        try:
            res = []
            out = subprocess.check_output(["hcitool", "scan"])  # Requires 'apt-get install bluez'
            out = out.split("\n")
            device_name_re = re.compile("^\t([0-9,:,A-F]{17})\t(.*)$")
            for line in out:
                device_name = device_name_re.match(line)
                if device_name != None:
                    res.append({
                            "mac_address": device_name.group(1),
                            "name": device_name.group(2)
                        })
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            return res

    def is_connected(self):
        """Returns True if there is a current connection to any device, otherwise returns False"""
        try:
            res = False
            out = subprocess.check_output(["hcitool", "con"])  # Requires 'apt-get install bluez'
            out = out.split("\n")
            mac_addr_re = re.compile("^.*([0-9,:,A-F]{17}).*$")
            for line in out:
                mac_addr = mac_addr_re.match(line)
                if mac_addr != None:
                    res = True
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            return res

    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

    def trust(self, mac_address):
        """Trust the device with the given MAC address"""
        try:
            out = self.get_output("trust " + mac_address, 4)
        except BluetoothctlError, e:
            print(e)
            return None
        else:
            res = self.child.expect(["not available", "trust succeeded", pexpect.EOF])
            success = True if res == 1 else False
            return success

    def start_agent(self):
        """Start agent"""
        try:
            out = self.get_output("agent on")
        except BluetoothctlError, e:
            print(e)
            return None

    def default_agent(self):
        """Start default agent"""
        try:
            out = self.get_output("default-agent")
        except BluetoothctlError, e:
            print(e)
            return None

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())

Added is_connected function - Returns True if there is a current BT connection to some device, otherwise returns False

I know the use of hcitool is not exactly warping the bluetoothctl, but bluetoothctl just does not have all the needed functionality. 😃

Hello,

Thank you very much for this code.
I am using python3 and there are some errors to compile it.
Is it possible to get this wrapper for python3?

Thanks in advance

If I start the agent and default-agent, how can I get the pi to answer the pair request, so that it can pair with the device?

I am getting this error when I try to connect to a device that is connected to another device, it should return "Failed to connect" but it's a TIMEOUT exception.

raise TIMEOUT(msg)
pexpect.exceptions.TIMEOUT: Timeout exceeded.
<pexpect.pty_spawn.spawn object at 0xb62e3ab0>
command: /usr/bin/bluetoothctl
args: ['/usr/bin/bluetoothctl']
buffer (last 100 chars): 'mCHG\x1b[0m] Device 98:5F:D3:57:1A:BD RSSI: -47\r\n[\x 1b[0;93mCHG\x1b[0m] Device 98:5F:D3:57:1A:BD TxPower: 4\r\n'
before (last 100 chars): 'mCHG\x1b[0m] Device 98:5F:D3:57:1A:BD RSSI: -47\r\n[\x 1b[0;93mCHG\x1b[0m] Device 98:5F:D3:57:1A:BD TxPower: 4\r\n'
after: <class 'pexpect.exceptions.TIMEOUT'>
match: None
match_index: None
exitstatus: None
flag_eof: False
pid: 544
child_fd: 5
closed: False
timeout: 30
delimiter: <class 'pexpect.exceptions.EOF'>
logfile: None
logfile_read: None
logfile_send: None
maxread: 2000
ignorecase: False
searchwindowsize: None
delaybeforesend: 0.05
delayafterclose: 0.1
delayafterterminate: 0.1
searcher: searcher_re:
0: re.compile("Failed to connect")
1: re.compile("Connection successful")
2: EOF

EDIT2: changed "start_failed = self.child.expect(["bluetooth", pexpect.EOF])" to "start_failed = self.child.expect( [ "#", pexpect.EOF ] )", and now it works even if you have another bluetooth deviced connected.

EDIT: I think I know where the problem is. the line "start_failed = self.child.expect(["bluetooth", pexpect.EOF])" is waiting for the bluetoothctl prompt to be "[bluetooth]", and when a device is already connected, the prompt is "[NAME OF THE DEVICE]". Now I'm figuring out how to make it ignore that.

---

Thanks for the code. Not sure if it's a bug, but if there's any other device already connected, the script gets stuck on "Ready!" message, and after a few second it stops and prints this:

Traceback (most recent call last):
File "scripts/bluetoothctl.py", line 270, in
bl.start_scan()
File "scripts/bluetoothctl.py", line 60, in start_scan
out = self.get_output("scan on")
File "scripts/bluetoothctl.py", line 50, in get_output
start_failed = self.child.expect(["bluetooth", pexpect.EOF])
File "/home/pi/.local/lib/python2.7/site-packages/pexpect/spawnbase.py", line 341, in expect
timeout, searchwindowsize, async_)
File "/home/pi/.local/lib/python2.7/site-packages/pexpect/spawnbase.py", line 369, in expect_list
return exp.expect_loop(timeout)
File "/home/pi/.local/lib/python2.7/site-packages/pexpect/expect.py", line 119, in expect_loop
return self.timeout(e)
File "/home/pi/.local/lib/python2.7/site-packages/pexpect/expect.py", line 82, in timeout
raise TIMEOUT(msg)
pexpect.exceptions.TIMEOUT: Timeout exceeded.
<pexpect.pty_spawn.spawn object at 0x769f98f0>
command: /usr/bin/bluetoothctl
args: ['/usr/bin/bluetoothctl']
buffer (last 100 chars): 'M30 Modkit]\x1b[0m# Discovery started\r\n[\x1b[0;93mCHG\x1b[0m] Controller B8:27:EB:94:DE:6D Discovering: yes\r\n'
before (last 100 chars): 'M30 Modkit]\x1b[0m# Discovery started\r\n[\x1b[0;93mCHG\x1b[0m] Controller B8:27:EB:94:DE:6D Discovering: yes\r\n'
after: <class 'pexpect.exceptions.TIMEOUT'>
match: None
match_index: None
exitstatus: None
flag_eof: False
pid: 688
child_fd: 5
closed: False
timeout: 30
delimiter: <class 'pexpect.exceptions.EOF'>
logfile: None
logfile_read: None
logfile_send: None
maxread: 1
ignorecase: False
searchwindowsize: None
delaybeforesend: 0.05
delayafterclose: 0.1
delayafterterminate: 0.1
searcher: searcher_re:
0: re.compile('bluetooth')
1: EOF

If you replace "bluetooth" with "(\x1b\\[0;94m)\\[.+\\](\x1b\\[0m)" it will work when connected to a device. This checks for any text between a set of brackets that's wrapped in the ansi color code bluetoothctl uses for the prompt text.

Thank you @ShibaSama that works great !

If pairing is not working, try calling the "connect" function this will automatically try attempting to pair the device to its client. This worked for me