a script to force productivity during deep work time

deep work script

#!/usr/local/bin/python3
#
# written 8/2/19 by jxm
#
# For some reason Chrome has its own DNS cache that makes websites
# still accessible sometimes after DNS is enabled. I considered adding
# code in this script to force-restart Chrome, but I'm going to forgo
# that for now until I find a better way to edit Chrome's settings 
# to disable DNS caching. (Or just use Firefox...)
#
# I saved this as /usr/local/bin/deepwork on my machine.
#
import sys

NOT_ALLOWED_SITES = [
        'facebook.com', 
        'twitter.com', 
        'reddit.com',
        '17.249.124.38' # I think this is the IP for Mac Desktop iMessage
        ]
HOST_FILE = '/etc/hosts'

FILE_START_LINE = '###### START DEEPWORK ######'
FILE_STOP_LINE =  '###### STOP DEEPWORK ######'

def _print_status(message):
    print('STATUS: ' + message)

def _print_error(message):
    print('ERROR: ' + message)

def _print_success(message):
    print('SUCCESS: ' + message)

def _keyword_lines_found_in_host_file():
    lines = open(HOST_FILE).readlines()
    start_found = 0 
    stop_found = 0 
    for line in lines:
        if FILE_START_LINE in line: start_found += 1
        if FILE_STOP_LINE in line: stop_found += 1
    return start_found, stop_found

def status():
    start_found, stop_found = _keyword_lines_found_in_host_file()
    if start_found == 0 and stop_found == 0:
        _print_status('deepwork not running.')
    elif start_found == 1 and stop_found == 1:
        _print_status('deepwork running.') # @TODO print blocked hosts 
    else:
        _print_status('deepwork corrupted file ' + HOST_FILE)

def start():
    if not _keyword_lines_found_in_host_file() == (0,0):
        _print_error('Cannot start; already running')
        exit()
    
    hosts_file = open(HOST_FILE, 'a+')

    # Write header
    hosts_file.write(FILE_START_LINE + '\n')
    # Write blocked hosts
    for site in NOT_ALLOWED_SITES:
        hosts_file.write('127.0.0.1 {}\n'.format(site))
        hosts_file.write('127.0.0.1 www.{}\n'.format(site))
    # Write footer
    hosts_file.write(FILE_STOP_LINE + '\n')

    _print_success('begin deep work! [restart browser if DNS resolution still succeeds]') 
            # @TODO: Track deep work time

def stop():
    if not _keyword_lines_found_in_host_file() == (1,1):
        _print_error('Cannot stop; not running')
        exit()

    hosts_file = open(HOST_FILE, 'r')
    keep_lines = True
    lines = []
    for line in hosts_file.readlines():
        if FILE_START_LINE in line:
            keep_lines = False
        elif FILE_STOP_LINE in line:
            keep_lines = True
        elif keep_lines:
            lines.append(line)
    hosts_file = open(HOST_FILE, 'w')
    for line in lines:
        hosts_file.write(line)
        if line[-1] != '\n':
            hosts_file.write('\n')
    hosts_file.close()
    _print_success('deep work ended')


def main():
    if not len(sys.argv) == 2:
        print("ERROR: Call script like `deepwork <command>`")
        exit()
    command = sys.argv[1]
    if command == 'status':
        status()
    elif command == 'start':
        start()
    elif command == 'stop':
        stop()
    else:
        print("ERROR: Valid commands are 'help', 'stop', or 'status'")
        exit()

if __name__ == '__main__': main()