at/at.py

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
import logging
import sqlite3
import threading
import traceback
import json
from flask import Flask, render_template, abort, redirect, session, request, flash, g
from datetime import datetime
from wsgiref import simple_server
from pesto import Response, dispatcher_app
from time import sleep, time
from collections import namedtuple
from urllib import urlencode
from hashlib import sha256

import config

app = Flask('at')
app.secret_key = config.secret_key
logger = logging.getLogger()
conn = None
updater = None

from functools import wraps

def restrict_ip(prefix='', exclude=[]):
    def decorator(f):
        @wraps(f)
        def func(*a, **kw):
            r_addr = request.remote_addr
            if not r_addr.startswith(prefix) or r_addr in exclude:
                abort(403)
            return f(*a, **kw)
        return func
    return decorator

def req_to_ctx():
    return dict(request.form.iteritems())

@app.template_filter('strfts')
def strfts(ts, format='%d/%m/%Y %H:%M'):
    return datetime.fromtimestamp(ts).strftime(format)

def setup_db():
    conn = sqlite3.connect(config.db)
    conn.row_factory = sqlite3.Row
    conn.isolation_level = None # for autocommit mode
    return conn

DeviceInfo = namedtuple('DeviceInfo', ['hwaddr', 'owner', 'ignored'])
User = namedtuple('User', ['login', 'passwd', 'url'])

def get_device_info(conn, hwaddr):
    return list(get_device_infos(conn, (hwaddrs,)))[0]

def get_device_infos(conn, hwaddrs):
    stmt = '''select hwaddr, name, ignored, login, url from 
        devices left join users on devices.owner = users.userid
        where devices.hwaddr in (''' + ','.join(['?'] * len(hwaddrs)) + ')'
    for row in conn.execute(stmt, hwaddrs):
        owner = User(row['login'], None, row['url']) if row['login'] else None
        ignored = row['ignored']
        yield DeviceInfo(row['hwaddr'], owner, ignored)

class Updater(threading.Thread):
    def __init__(self,  timeout, *a, **kw):
        self.timeout = timeout
        self.lock = threading.Lock()
        self.active = {}
        threading.Thread.__init__(self, *a, **kw)
    def purge_stale(self):
        now = time()
        for addr, (atime, ip, name) in self.active.items():
            if now - atime > self.timeout:
                del self.active[addr]
    def get_active_devices(self):
        self.lock.acquire()
        self.purge_stale()
        r = dict(self.active)
        self.lock.release()
        return r
    def get_device(self, ip):
        for hwaddr, (atime, dip, name) in \
            self.get_active_devices().iteritems():
            if ip == dip:
                return hwaddr, name
        return None, None
    def update(self, hwaddr, atime = None, ip = None, name = None):
        atime = atime or time()
        self.lock.acquire()
        self.active[hwaddr] = (atime, ip, name)
        self.lock.release()
        logger.info('updated %s with atime %s and ip %s',
            hwaddr, strfts(atime), ip)

class CapUpdater(Updater):
    def __init__(self, cap_file, *a, **kw):
        self.cap_file = cap_file
        Updater.__init__(self, *a, **kw)
    def run(self):
        while True:
            try:
                with open(self.cap_file, 'r', buffering=0) as f:
                    logger.info('Updater ready on cap file %s', self.cap_file)
                    while True:
                        hwaddr = f.readline().strip()
                        if not hwaddr:
                            break
                        self.update(hwaddr)
                logging.warning('Cap file %s closed, reopening', self.cap_file)
            except Exception as e:
                logging.error('Updater got an exception:\n' + \
                    traceback.format_exc(e))
                sleep(10.0)

class DnsmasqUpdater(Updater):
    def __init__(self, lease_file, lease_offset, *a, **kw):
        self.lease_file = lease_file
        self.lease_offset = lease_offset
        self.last_modified = 0
        Updater.__init__(self, *a, **kw)
    def run(self):
        import os
        while True:
            try:
                mtime = os.stat(self.lease_file).st_mtime
                if mtime > self.last_modified:
                    logger.info('Lease file changed, updating')
                    with open(self.lease_file, 'r') as f:
                        for line in f:
                            ts, hwaddr, ip, name, client_id = line.split(' ')
                            self.update(hwaddr, int(ts) - self.lease_offset, ip, name)
                self.last_modified = mtime
                sleep(3.0)
            except Exception as e:
                logging.error('Updater got an exception:\n' + \
                    traceback.format_exc(e))
                sleep(10.0)
        
@app.route('/')
def main_view():
    return render_template('main.html', **now_at())

@app.route('/api')
def list_all():
    result = now_at()
    def prettify_user((user, atime)):
        return {
            'login': user.login,
            'timestamp': atime,
            'pretty_time': strfts(atime),
            'url': user.url,
        }
    result['users'] = map(prettify_user, result['users'])
    result['unknown'] = len(result['unknown'])
    del result['login']
    return json.dumps(result)

def now_at():
    devices = updater.get_active_devices()
    device_infos = list(get_device_infos(conn, devices.keys()))
    device_infos.sort(key=lambda di: devices.__getitem__)
    users = list(dict((info.owner, devices[info.hwaddr][0]) for info in device_infos 
        if info.owner and not info.ignored).iteritems())
    users.sort(key=lambda (u, a): a, reverse=True)
    unknown = set(devices.keys()) - set(d.hwaddr for d in device_infos)
    return dict(users=users, unknown=unknown, login=session.get('login'))

restrict_to_hs = restrict_ip(prefix=config.claimable_prefix, 
    exclude=config.claimable_exclude)

@app.route('/register', methods=['GET'])
@restrict_to_hs
def register_form():
    return render_template('register.html', **req_to_ctx())

@app.route('/register', methods=['POST'])
@restrict_to_hs
def register():
    login = request.form['login']
    url = request.form['url']
    if 'wiki' in request.form:
        url = config.wiki_url % { 'login': login }
    try:
        conn.execute('insert into users (login, url, pass) values (?, ?, ?)',
            [login, url, sha256(request.form['password']).hexdigest()])
        return redirect('/')
    except sqlite3.Error as e:
        flash('Cannot add user - username taken?', category='error')
        return register_form()

@app.route('/login', methods=['GET'])
@restrict_to_hs
def login_form():
    return render_template('login.html', **req_to_ctx())

def get_credentials(login, password):
    row = conn.execute('select userid from users where login = ? and pass = ?',
        [login, sha256(password).hexdigest()]).fetchone()
    return row and row['userid']

@app.route('/login', methods=['POST'])
@restrict_to_hs
def login():
    login = request.form.get('login', '')
    pwd = request.form.get('password', '')
    goto = request.values.get('goto') or '/'
    userid = get_credentials(login, pwd)
    if userid:
        session['userid'] = userid
        session['login'] = login
        return redirect(goto)
    else:
        flash('Username or password invalid', category='error')
        return login_form()

@app.route('/logout')
@restrict_to_hs
def logout():
    session.clear()
    return redirect('/')

def login_required(f):
    @wraps(f)
    def func(*a, **kw):
        if 'userid' not in session:
            flash('You must log in to continue', category='error')
            return redirect('/login?' + 
                urlencode({'goto': request.path}))
        return f(*a, **kw)
    return func

@app.route('/claim', methods=['GET'])
@restrict_to_hs
@login_required
def claim_form():
    hwaddr, name = updater.get_device(request.remote_addr)
    return render_template('claim.html', hwaddr=hwaddr, name=name, 
        login=session['login'])

@app.route('/claim', methods=['POST'])
@restrict_to_hs
@login_required
def claim():
    hwaddr, lease_name = updater.get_device(request.remote_addr)
    ctx = None
    if not hwaddr:
        ctx = { 'error': 'Invalid device.' }
    else:
        userid = session['userid']
        try:
            conn.execute('insert into devices (hwaddr, name, owner, ignored)\
                values (?, ?, ?, ?)', [hwaddr, request.form['name'], userid, False])
            ctx = {}
        except sqlite3.Error as e:
            ctx = { 'error': 'Could not add device! Perhaps someone claimed it?' }
    return render_template('post_claim.html', **ctx)

port = 8080
if __name__ == '__main__':
    logger.setLevel(logging.DEBUG)
    logger.addHandler(logging.StreamHandler())
    conn = setup_db()
    updater = DnsmasqUpdater(config.lease_file, config.lease_offset, config.timeout)
    updater.start()
    app.run('0.0.0.0', config.port)