e2restream

e2restream.py

#!/usr/bin/python2.7

""" e2restream Deamon """

import os
import sys
import time
import atexit
import Queue
import hashlib

from threading import Thread, Lock
from signal import SIGTERM

import requests 
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
from SocketServer import ThreadingMixIn
from urllib import unquote

HOST_NAME = ""
PORT_NUMBER = 888
RELAYS = {}
MUTEX = Lock()

### http://pymotw.com/2/select/
### http://stackoverflow.com/questions/16694907/how-to-download-large-file-in-python-with-requests-py


def md5(url):
    m = hashlib.md5()
    m.update(url)
    return m.hexdigest()


def RequestsData(url):
    global RELAYS
    urlhash = md5(url)
    res = requests.get(url, stream=True)
    for chunk in res.iter_content(chunk_size=192*1024): 
        if chunk: # filter out keep-alive new chunks
            with MUTEX:
                if not urlhash in RELAYS:
                    break
                for q in RELAYS[urlhash]:
                    RELAYS[urlhash][q].put(chunk)


def Stream(wfile, url):
    global RELAYS
    client = wfile.fileno()
    urlhash = md5(url)
    if urlhash in RELAYS:
        with MUTEX:
            RELAYS[urlhash][client] = Queue.Queue()
    else:
        with MUTEX:
            RELAYS[urlhash] = {}
            RELAYS[urlhash][client] = Queue.Queue()
        thread = Thread(target=RequestsData, args=(url,))
        thread.start()

    while True:
        try:
            data = RELAYS[urlhash][client].get(True,15)
        except Queue.Empty:
            with MUTEX:
                del RELAYS[urlhash][client]
            break
        else:
            try:
                wfile.write(data)
            except:
                break

    if client in RELAYS[urlhash]:
        with MUTEX:
            del RELAYS[urlhash][client]

    if len(RELAYS[urlhash]) == 0:
        del RELAYS[urlhash]

    wfile.close()

class StreamHandler(BaseHTTPRequestHandler):

    def do_HEAD(s):
        s.send_response(200)
        s.send_header("Server", "e2restream")
        s.send_header("Content-type", "text/html")
        s.end_headers()

    def do_GET(s):
        """Respond to a GET request."""
        s.send_response(200)
        s.send_header("Server", "e2restream")
        s.send_header("Content-type", "application/octet-stream")
        s.end_headers()

        url=unquote(s.path[1:])
        s.log_message("URL: %s", url)
        Stream(s.wfile, url)


class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
    """Handle requests in a separate thread."""


def start():
    httpd = ThreadedHTTPServer((HOST_NAME, PORT_NUMBER), StreamHandler)
    print time.asctime(), "Server Starts - %s:%s" % (HOST_NAME, PORT_NUMBER)
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        pass
    httpd.server_close()
    print time.asctime(), "Server Stops - %s:%s" % (HOST_NAME, PORT_NUMBER)


class Daemon:
	"""
	A generic daemon class.
	
	Usage: subclass the Daemon class and override the run() method
	"""
	def __init__(self, pidfile, stdin="/dev/null", stdout="/dev/null", stderr="/dev/null"):
		self.stdin = stdin
		self.stdout = stdout
		self.stderr = stderr
		self.pidfile = pidfile
	
	def daemonize(self):
		"""
		do the UNIX double-fork magic, see Stevens' "Advanced 
		Programming in the UNIX Environment" for details (ISBN 0201563177)
		http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
		"""
		try: 
			pid = os.fork() 
			if pid > 0:
				# exit first parent
				sys.exit(0) 
		except OSError, e: 
			sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
			sys.exit(1)
	
		# decouple from parent environment
		os.chdir("/") 
		os.setsid() 
		os.umask(0) 
	
		# do second fork
		try: 
			pid = os.fork() 
			if pid > 0:
				# exit from second parent
				sys.exit(0) 
		except OSError, e: 
			sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
			sys.exit(1) 
	
		# redirect standard file descriptors
		sys.stdout.flush()
		sys.stderr.flush()
		si = file(self.stdin, "r")
		so = file(self.stdout, "a+")
		se = file(self.stderr, "a+", 0)
		os.dup2(si.fileno(), sys.stdin.fileno())
		os.dup2(so.fileno(), sys.stdout.fileno())
		os.dup2(se.fileno(), sys.stderr.fileno())
	
		# write pidfile
		atexit.register(self.delpid)
		pid = str(os.getpid())
		file(self.pidfile,"w+").write("%s\n" % pid)
	
	def delpid(self):
		os.remove(self.pidfile)

	def start(self):
		"""
		Start the daemon
		"""
		# Check for a pidfile to see if the daemon already runs
		try:
			pf = file(self.pidfile,"r")
			pid = int(pf.read().strip())
			pf.close()
		except IOError:
			pid = None
	
		if pid:
			message = "pidfile %s already exist. Daemon already running?\n"
			sys.stderr.write(message % self.pidfile)
			sys.exit(1)
		
		# Start the daemon
		self.daemonize()
		self.run()

	def stop(self):
		"""
		Stop the daemon
		"""
		# Get the pid from the pidfile
		try:
			pf = file(self.pidfile,"r")
			pid = int(pf.read().strip())
			pf.close()
		except IOError:
			pid = None
	
		if not pid:
			message = "pidfile %s does not exist. Daemon not running?\n"
			sys.stderr.write(message % self.pidfile)
			return # not an error in a restart

		# Try killing the daemon process	
		try:
			while 1:
				os.kill(pid, SIGTERM)
				time.sleep(0.1)
		except OSError, err:
			err = str(err)
			if err.find("No such process") > 0:
				if os.path.exists(self.pidfile):
					os.remove(self.pidfile)
			else:
				print str(err)
				sys.exit(1)

	def restart(self):
		"""
		Restart the daemon
		"""
		self.stop()
		self.start()

	def run(self):
		"""
		You should override this method when you subclass Daemon. It will be called after the process has been
		daemonized by start() or restart().
		"""


class e2restreamDaemon(Daemon):
    def run(self):
        start()


if __name__ == "__main__":
    daemon = e2restreamDaemon("/var/run/e2restream.pid")
    if len(sys.argv) == 2:
        if "start" == sys.argv[1]:
            daemon.start()
        elif "stop" == sys.argv[1]:
            daemon.stop()
        elif "restart" == sys.argv[1]:
            daemon.restart()
        elif "manualstart" == sys.argv[1]:
            start()
        else:
            print "Unknown command"
            sys.exit(2)
        sys.exit(0)
    else:
        print "usage: %s start|stop|restart|manualstart" % sys.argv[0]
        sys.exit(2)