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#!/usr/bin/python3
# CodeQ: an online programming tutor.
# Copyright (C) 2015 UL FRI
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program 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 Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This file must be run on the EV3 brick. It serves websocket connections,
# sending sensor updates and running user programs.
PORT = 8000
from fcntl import fcntl, F_GETFL, F_SETFL
import io
import json
import os
import os.path
import signal
import subprocess
import time
import engineio
import eventlet
import ev3dev
ev3_names = {
'lego-ev3-color': 'Color',
'lego-ev3-gyro': 'Gyroscope',
'lego-ev3-touch': 'Touch',
'lego-ev3-us': 'Ultrasonic'
}
ev3_motors = [
ev3dev.motor(ev3dev.OUTPUT_A),
ev3dev.motor(ev3dev.OUTPUT_B),
ev3dev.motor(ev3dev.OUTPUT_C),
ev3dev.motor(ev3dev.OUTPUT_D)
]
connections = set()
running = False
# Make a Python interpreter ready for running user program.
def start_interpreter():
global running
process = subprocess.Popen(['python3', '-u'], bufsize=1, universal_newlines=True,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
# Set the non-blocking flag for stdout.
flags = fcntl(process.stdout.fileno(), F_GETFL)
fcntl(process.stdout.fileno(), F_SETFL, flags | os.O_NONBLOCK)
process.stdin.write("import ev3dev\n")
process.stdin.write("from mindstorms_widgets import mindstorms_widgets\n")
running = False
return process
process = start_interpreter()
def run(program):
global process, running
if running:
stop()
running = True
process.stdin.write("exec('''" + program + "''')\n")
process.stdin.close()
def stop():
global process
if process is not None:
try:
os.kill(process.pid, signal.SIGKILL)
except:
pass
for motor in ev3_motors:
if motor.connected:
motor.stop(stop_command='brake')
process = start_interpreter()
def notifier():
global process
sensors_path = '/sys/class/lego-sensor'
sensors = {}
for sensor in os.listdir(sensors_path):
path = os.path.join(sensors_path, sensor)
with open(os.path.join(path, 'driver_name'), 'r') as f:
name = f.read().strip()
with open(os.path.join(path, 'decimals'), 'r') as f:
decimals = int(f.read().strip())
multiplier = 10**(-decimals)
with open(os.path.join(path, 'units'), 'r') as f:
unit = f.read().strip()
friendly_name = ev3_names.get(name, name)
sensors[path] = (friendly_name, multiplier, unit)
while True:
try:
if running:
text = process.stdout.readline()
if text:
message = {'event': 'output', 'text': text}
for sid in connections:
eio.send(sid, json.dumps(message))
continue
if process.poll() is not None:
process = start_interpreter()
message = {'event': 'update', 'sensors': {}}
for path, (name, multiplier, unit) in sorted(sensors.items()):
with open(os.path.join(path, 'value0'), 'rb') as f:
value = round(int(f.read().strip()) * multiplier, 1)
if unit:
value = '{} {}'.format(value, unit)
message['sensors'][name] = value
text = json.dumps(message)
for sid in connections:
eio.send(sid, text)
except:
pass
eventlet.sleep(0.2)
eio = engineio.Server(async_mode='eventlet', cookie=None)
app = engineio.Middleware(eio)
@eio.on('connect')
def connect(sid, environ):
print('New connection: {}'.format(sid))
connections.add(sid)
@eio.on('disconnect')
def disconnect(sid):
print('Dropped connection: {}'.format(sid))
try:
connections.remove(sid)
except:
pass
@eio.on('message')
def message(sid, msg):
reply = None
action = msg.get('action')
if action is None:
reply = {'code': 1, 'message': 'Request does not contain an action'}
elif action == 'run':
program = msg.get('program')
if program is None:
reply = {'code': 2, 'message': 'Program not specified'}
else:
run(program)
reply = {'code': 0}
elif action == 'stop':
stop()
reply = {'code': 0}
eio.send(sid, reply)
eventlet.spawn_n(notifier)
eventlet.wsgi.server(eventlet.listen(('', PORT)), app)
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