#!/usr/bin/python
# -*- coding: utf-8 -*-

# Licensed under GNU General Public License v3 or later
# Written by Sebastian Lohff (seba@seba-geek.de)
# http://seba-geek.de/stuff/servefile/

from __future__ import print_function

__version__ = '0.4.2'

import argparse
import base64
import cgi
import datetime
import mimetypes
import urllib
import os
import posixpath
import re
import select
import socket
from subprocess import Popen, PIPE
import sys
import time

# fix imports for python2/python3
try:
    import BaseHTTPServer
    import SocketServer
except ImportError:
    # both have different names in python3
    import http.server as BaseHTTPServer
    import socketserver as SocketServer

# only activate SSL if available
HAVE_SSL = False
try:
	from OpenSSL import SSL, crypto
	HAVE_SSL = True
except ImportError:
	pass

def getDateStrNow():
	""" Get the current time formatted for HTTP header """
	now = datetime.datetime.fromtimestamp(time.mktime(time.gmtime()))
	return now.strftime("%a, %d %b %Y %H:%M:%S GMT")

class FileBaseHandler(BaseHTTPServer.BaseHTTPRequestHandler):
	fileName = None
	blockSize = 1024 * 1024
	server_version = "servefile/" + __version__

	def checkAndDoRedirect(self, fileName=None):
		""" If request didn't request self.fileName redirect to self.fileName.

		Returns True if a redirect was issued. """
		if not fileName:
			fileName = self.fileName
		if urllib.unquote(self.path) != "/" + fileName:
			self.send_response(302)
			self.send_header('Location', '/' + fileName)
			self.end_headers()
			return True
		return False

	def sendContentHeaders(self, fileName, fileLength, lastModified=None):
		""" Send default Content headers for given fileName and fileLength.

		If no lastModified is given the current date is taken. If
		fileLength is lesser than 0 no Content-Length will be sent."""
		if not lastModified:
			lastModified = getDateStrNow()

		if fileLength >= 0:
			self.send_header('Content-Length', str(fileLength))
		self.send_header('Last-Modified', lastModified)
		self.send_header('Content-Type', 'application/octet-stream')
		self.send_header('Content-Disposition', 'attachment; filename="%s"' % fileName)
		self.send_header('Content-Transfer-Encoding', 'binary')

	def isRangeRequest(self):
		""" Return True if partial content is requestet """
		return "Range" in self.headers

	def handleRangeRequest(self, fileLength):
		""" Find out and handle continuing downloads.

		Returns a tuple of a boolean, if this is a valid range request,
		and a range. When the requested range is out of range, range is
		set to None.
		"""
		fromto = None
		if self.isRangeRequest():
			cont = self.headers.get("Range").split("=")
			if len(cont) > 1 and cont[0] == 'bytes':
				fromto = cont[1].split('-')
				if len(fromto) > 1:
					if fromto[1] == '':
						fromto[1] = fileLength - 1
					try:
						fromto[0] = int(fromto[0])
						fromto[1] = int(fromto[1])
					except:
						return (False, None)

					if fromto[0] >= fileLength or fromto[0] < 0 or fromto[1] >= fileLength or fromto[1]-fromto[0] < 0:
						# oops, already done! (requested range out of range)
						self.send_response(416)
						self.send_header('Content-Range', 'bytes */%d' % fileLength)
						self.end_headers()
						return (True, None)
					return (True, fromto)
		# broken request or no range header
		return (False, None)

	def sendFile(self, filePath, fileLength=None, lastModified=None):
		""" Send file with continuation support.

		filePath: path to file to be sent
		fileLength: length of file (if None is given this will be found out)
		lastModified: time the file was last modified, None for "now"
		"""
		if not fileLength:
			fileLength = os.stat(filePath).st_size

		(responseCode, myfile) = self.getFileHandle(filePath)
		if not myfile:
			self.send_response(responseCode)
			self.end_headers()
			return

		(continueDownload, fromto) = self.handleRangeRequest(fileLength)
		if continueDownload:
			if not fromto:
				# we are done
				return True

			# now we can wind the file *brrrrrr*
			myfile.seek(fromto[0])

		if fromto != None:
			self.send_response(216)
			self.send_header('Content-Range', 'bytes %d-%d/%d' % (fromto[0], fromto[1], fileLength))
			fileLength = fromto[1] - fromto[0] + 1
		else:
			self.send_response(200)

		fileName = self.fileName
		if not fileName:
			fileName = os.path.basename(filePath)
		self.sendContentHeaders(fileName, fileLength, lastModified)
		self.end_headers()
		block = self.getChunk(myfile, fromto)
		while block:
			try:
				self.wfile.write(block)
			except socket.error as e:
				print("%s ABORTED transmission (Reason %s: %s)" % (self.client_address[0], e[0], e[1]))
				return False
			block = self.getChunk(myfile, fromto)
		myfile.close()
		print("%s finished downloading %s" % (self.client_address[0], filePath))
		return True

	def getChunk(self, myfile, fromto):
		if fromto and myfile.tell()+self.blockSize >= fromto[1]:
			readsize = fromto[1]-myfile.tell()+1
		else:
			readsize = self.blockSize
		return myfile.read(readsize)

	def getFileHandle(self, path):
		""" Get handle to a file.

		Return a tuple of HTTP response code and file handle.
		If the handle couldn't be acquired it is set to None
		and an appropriate HTTP error code is returned.
		"""
		myfile = None
		responseCode = 200
		try:
			myfile = open(path, 'rb')
		except IOError as e:
			responseCode = self.getResponseForErrno(e.errno)
		return (responseCode, myfile)

	def getFileLength(self, path):
		""" Get length of a file.

		Return a tuple of HTTP response code and file length.
		If filelength couldn't be determined, it is set to -1
		and an appropriate HTTP error code is returned.
		"""
		fileSize = -1
		responseCode = 200
		try:
			fileSize = os.stat(path).st_size
		except IOError as e:
			responseCode = self.getResponseForErrno(e.errno)
		return (responseCode, fileSize)

	def getResponseForErrno(self, errno):
		""" Return HTTP response code for an IOError errno """
		if errno == errno.ENOENT:
			return 404
		elif errno == errno.EACCESS:
			return 403
		else:
			return 500


class FileHandler(FileBaseHandler):
	filePath = "/dev/null"
	fileLength = 0
	startTime = getDateStrNow()

	def do_HEAD(self):
		if self.checkAndDoRedirect():
			return
		self.send_response(200)
		self.sendContentHeaders(self.fileName, self.fileLength, self.startTime)
		self.end_headers()

	def do_GET(self):
		if self.checkAndDoRedirect():
			return
		self.sendFile(self.filePath, self.fileLength, self.startTime)


class TarFileHandler(FileBaseHandler):
	target = None
	compression = "none"
	compressionMethods = ("none", "gzip", "bzip2")

	def do_HEAD(self):
		if self.checkAndDoRedirect():
			return
		self.send_response(200)
		self.sendContentHeaders(self.fileName, -1)
		self.end_headers()

	def do_GET(self):
		if self.checkAndDoRedirect():
			return

		tarCmd = Popen(self.getCompressionCmd(), stdout=PIPE)
		# give the process a short time to find out if it can
		# pack/compress the file
		time.sleep(0.05)
		if tarCmd.poll() != None and tarCmd.poll() != 0:
			# something went wrong
			print("Error while compressing '%s'. Aborting request." % self.target)
			self.send_response(500)
			self.end_headers()
			return

		self.send_response(200)
		self.sendContentHeaders(self.fileName, -1)
		self.end_headers()

		block = True
		while block and block != '':
			block = tarCmd.stdout.read(self.blockSize)
			if block and block != '':
				self.wfile.write(block)
		print("%s finished downloading" % (self.client_address[0]))

	def getCompressionCmd(self):
		if self.compression == "none":
			cmd = ["tar", "-c"]
		elif self.compression == "gzip":
			cmd = ["tar", "-cz"]
		elif self.compression == "bzip2":
			cmd = ["tar", "-cj"]
		else:
			raise ValueError("Unknown compression mode '%s'." % self.compression)

		dirname = os.path.basename(self.target.rstrip("/"))
		chdirTo = os.path.dirname(self.target.rstrip("/"))
		if chdirTo != '':
			cmd.extend(["-C", chdirTo])
		cmd.append(dirname)
		return cmd

	@staticmethod
	def getCompressionExt():
		if TarFileHandler.compression == "none":
			return ".tar"
		elif TarFileHandler.compression == "gzip":
			return ".tar.gz"
		elif TarFileHandler.compression == "bzip2":
			return ".tar.bz2"
		raise ValueError("Unknown compression mode '%s'." % TarFileHandler.compression)


class DirListingHandler(FileBaseHandler):
	""" DOCUMENTATION MISSING """

	targetDir = None

	def do_HEAD(self):
		self.getFileOrDirectory(head=True)

	def do_GET(self):
		self.getFileOrDirectory(head=False)

	def getFileOrDirectory(self, head=False):
		""" Send file or directory index, depending on requested path """
		path = self.getCleanPath()

		if os.path.isdir(path):
			if not self.path.endswith('/'):
				self.send_response(301)
				self.send_header("Location", self.path + '/')
				self.end_headers()
			else:
				self.sendDirectoryListing(path, head)
		elif os.path.isfile(path):
			if head:
				(response, length) = self.getFileLength(path)
				if length < 0:
					self.send_response(response)
					self.end_headers()
				else:
					self.send_response(200)
					self.sendContentHeaders(self, path, length)
					self.end_headers()
			else:
				self.sendFile(path, head)
		else:
			self.send_response(404)
			errorMsg = """<!DOCTYPE html><html>
				<head><title>404 Not Found</title></head>
				<body>
				<h1>Not Found</h1>
				<p>The requestet URL %s was not found on this server</p>
				<p><a href="/">Back to /</a>
				</body>
				</html>""" % self.escapeHTML(urllib.unquote(self.path))
			self.send_header("Content-Length", str(len(errorMsg)))
			self.end_headers()
			if not head:
				self.wfile.write(errorMsg)

	def escapeHTML(self, htmlstr):
		entities = [("<", "&lt;"), (">", "&gt;")]
		for src, dst in entities:
			htmlstr = htmlstr.replace(src, dst)
		return htmlstr

	def sendDirectoryListing(self, path, head):
		""" Generate a directorylisting for path and send it """
		header = """<!DOCTYPE html>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
		<title>Index of %(path)s</title>
		<style type="text/css">
			a { text-decoration: none; color: #0000BB;}
			a:visited { color: #000066;}
			a:hover, a:focus, a:active { text-decoration: underline; color: #cc0000; text-indent: 5px; }
			body { background-color: #eaeaea; padding: 20px 0; margin: 0; font: 400 13px/1.2em Arial, sans-serif; }
			h1 { margin: 0 10px 12px 10px; font-family: Arial, sans-serif; }
			div.content { background-color: white; border-color: #ccc; border-width: 1px 0; border-style: solid; padding: 10px 10px 15px 10px; }
			td { padding-right: 15px; text-align: left; font-family: monospace; }
			th { font-weight: bold; font-size: 115%%; padding: 0 15px 5px 0; text-align: left; }
			.size { text-align: right; }
			.footer { font: 12px monospace; color: #333; margin: 5px 10px 0; }
			.footer, h1 { text-shadow: 0 1px 0 white; }
		</style>
	</head>
<body>
	<h1>Index of %(path)s</h1>
	<div class="content">
	<table summary="Directory Listing">
		<thead>
			<tr>
				<th class="name">Name</th>
				<th class="lastModified">Last Modified</th>
				<th class="size">Size</th>
				<th class="type">Type</th>
			</tr>
		</thead>
		<tbody>
		""" % {'path': posixpath.normpath(urllib.unquote(self.path))}
		footer = """</tbody></table></div>
<div class="footer"><a href="http://seba-geek.de/stuff/servefile/">servefile %(version)s</a></div>
</body>
</html>""" % {'version': __version__}
		content = []
		for item in [".."] + sorted(os.listdir(path)):
				# create path to item
				itemPath = os.path.join(path, item)

				# try to stat file for size, last modified... continue on error
				stat = None
				try:
					stat = os.stat(itemPath)
				except IOError:
					continue

				# Strings to display on directory listing
				lastModifiedDate = datetime.datetime.fromtimestamp(stat.st_mtime)
				lastModified = lastModifiedDate.strftime("%Y-%m-%d %H:%M")
				fileSize = "%.1f%s" % self.convertSize(stat.st_size)
				(fileType, _) = mimetypes.guess_type(itemPath)
				if not fileType:
					fileType = "-"

				if os.path.isdir(itemPath):
					item += "/"
					fileType = "Directory"
				content.append("""
					<tr>
						<td class="name"><a href="%s">%s</a></td>
						<td class="last-modified">%s</td>
						<td class="size">%s</td>
						<td class="type">%s</td>
					</tr>""" % (urllib.quote(item), item, lastModified, fileSize, fileType))

		listing = header + "\n".join(content) + footer

		# write listing
		self.send_response(200)
		self.send_header("Content-Type", "text/html")
		if head:
			self.end_headers()
			return
		self.send_header("Content-Length", str(len(listing)))
		self.end_headers()
		self.wfile.write(listing)

	def convertSize(self, size):
		for ext in "KMGT":
			size /= 1024.0
			if size < 1024.0:
				break
		if ext == "K" and size < 0.1:
			size = 0.1
		return (size, ext.strip())

	def getCleanPath(self):
		urlPath = posixpath.normpath(urllib.unquote(self.path)).strip("/")
		path = os.path.join(self.targetDir, urlPath)
		return path


class FilePutter(BaseHTTPServer.BaseHTTPRequestHandler):
	""" Simple HTTP Server which allows uploading to a specified directory
	either via multipart/form-data or POST/PUT requests containing the file.
	"""

	targetDir = None
	maxUploadSize = 0
	blockSize = 1024 * 1024
	uploadPage = """
<!docype html>
<html>
	<form action="/" method="post" enctype="multipart/form-data">
		<label for="file">Filename:</label>
		<input type="file" name="file" id="file" />
		<br />
		<input type="submit" name="submit" value="Upload" />
	</form>
</html>
"""

	def do_GET(self):
		""" Answer every GET request with the upload form """
		self.sendResponse(200, self.uploadPage)

	def do_POST(self):
		""" Upload a file via POST

		If the content-type is multipart/form-data it checks for the file
		field and saves the data to disk. For other content-types it just
		calls do_PUT and is handled as such except for the http response code.

		Files can be uploaded with wget --post-file=path/to/file <url> or
		curl -X POST -d @file <url> .
		"""
		length = self.getContentLength()
		if length < 0:
			return
		ctype = self.headers.getheader('Content-Type')

		# check for multipart/form-data.
		if not (ctype and ctype.lower().startswith("multipart/form-data")):
			# not a normal multipart request ==> handle as PUT request
			return self.do_PUT(fromPost=True)

		# create FieldStorage object for multipart parsing
		env = os.environ
		env['REQUEST_METHOD'] = "POST"
		fstorage = cgi.FieldStorage(fp=self.rfile, headers=self.headers, environ=env)
		if not "file" in fstorage:
			self.sendResponse(400, "No file found in request.")
			return

		destFileName = self.getTargetName(fstorage["file"].filename)
		if destFileName == "":
			self.sendResponse(400, "Filename was empty or invalid")
			return

		# write file down to disk, send a 200 afterwards
		target = open(destFileName, "w")
		bytesLeft = length
		while bytesLeft > 0:
			bytesToRead = min(self.blockSize, bytesLeft)
			target.write(fstorage["file"].file.read(bytesToRead))
			bytesLeft -= bytesToRead
		target.close()
		self.sendResponse(200, "OK! Thanks for uploading")
		print("Received file '%s' from %s." % (destFileName, self.client_address[0]))

	def do_PUT(self, fromPost=False):
		""" Upload a file via PUT

		The request path is used as filename, so uploading a file to the url
		http://host:8080/testfile will cause the file to be named testfile. If
		no filename is given, a random name will be generated.

		Files can be uploaded with e.g. curl -X POST -d @file <url> .
		"""
		length = self.getContentLength()
		if length < 0:
			return

		fileName = urllib.unquote(self.path)
		if fileName == "/":
			# if no filename was given we have to generate one
			fileName = str(time.time())

		cleanFileName = self.getTargetName(fileName)
		if cleanFileName == "":
			self.sendResponse(400, "Filename was invalid")
			return

		# Sometimes clients want to be told to continue with their transfer
		if self.headers.getheader("Expect") == "100-continue":
			self.send_response(100)
			self.end_headers()

		target = open(cleanFileName, "w")
		bytesLeft = int(self.headers['Content-Length'])
		while bytesLeft > 0:
			bytesToRead = min(self.blockSize, bytesLeft)
			target.write(self.rfile.read(bytesToRead))
			bytesLeft -= bytesToRead
		target.close()
		self.sendResponse(200 if fromPost else 201, "OK!")

	def getContentLength(self):
		length = 0
		try:
			length = int(self.headers['Content-Length'])
		except (ValueError, KeyError):
			pass
		if length <= 0:
			self.sendResponse(411, "Content-Length was invalid or not set.")
			return -1
		if self.maxUploadSize > 0 and length > self.maxUploadSize:
			self.sendResponse(413, "Your file was too big! Maximum allowed size is %d byte. <a href=\"/\">back</a>" % self.maxUploadSize)
			return -1
		return length

	def sendResponse(self, code, msg):
		""" Send a HTTP response with HTTP statuscode code and message msg,
		providing the correct content-length.
		"""
		self.send_response(code)
		self.send_header('Content-Type', 'text/html')
		self.send_header('Content-Length', str(len(msg)))
		self.end_headers()
		self.wfile.write(msg)

	def getTargetName(self, fname):
		""" Generate a clean and secure filename.

		This function takes a filename and strips all the slashes out of it.
		If the file already exists in the target directory, a (NUM) will be
		appended, so no file will be overwritten.
		"""
		cleanFileName = fname.replace("/", "")
		if cleanFileName == "":
			return ""
		destFileName = os.path.join(self.targetDir, cleanFileName)
		if not os.path.exists(destFileName):
			return destFileName
		else:
			i = 1
			extraDestFileName = destFileName + "(%s)" % i
			while os.path.exists(extraDestFileName):
				i += 1
				extraDestFileName = destFileName + "(%s)" % i
			return extraDestFileName
		# never reached

class ThreadedHTTPServer(SocketServer.ThreadingMixIn, BaseHTTPServer.HTTPServer):
	pass

def catchSSLErrors(BaseSSLClass):
	""" Class decorator which catches SSL errors and prints them. """
	class X(BaseSSLClass):
		def handle_one_request(self, *args, **kwargs):
			try:
				BaseSSLClass.handle_one_request(self, *args, **kwargs)
			except SSL.Error as e:
				if str(e) == "":
					print("%s SSL error (empty error message)" % (self.client_address[0],))
				else:
					print("%s SSL error: %s" % (self.client_address[0], e))
	return X


class SecureThreadedHTTPServer(ThreadedHTTPServer):
	def __init__(self, pubKey, privKey, server_address, RequestHandlerClass, bind_and_activate=True):
		ThreadedHTTPServer.__init__(self, server_address, RequestHandlerClass, bind_and_activate)
		ctx = SSL.Context(SSL.SSLv23_METHOD)
		if type(pubKey) is crypto.X509 and type(privKey) is crypto.PKey:
			ctx.use_certificate(pubKey)
			ctx.use_privatekey(privKey)
		else:
			ctx.use_certificate_file(pubKey)
			ctx.use_privatekey_file(privKey)

		self.bsocket = socket.socket(self.address_family, self.socket_type)
		self.socket = SSL.Connection(ctx, self.bsocket)

		if bind_and_activate:
			self.server_bind()
			self.server_activate()

	def shutdown_request(self, request):
		request.shutdown()


class SecureHandler():
	def setup(self):
		self.connection = self.request
		self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
		self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)

class ServeFileException(Exception):
	pass


class ServeFile():
	""" Main class to manage everything. """

	_NUM_MODES = 4
	(MODE_SINGLE, MODE_SINGLETAR, MODE_UPLOAD, MODE_LISTDIR) = range(_NUM_MODES)

	def __init__(self, target, port=8080, serveMode=0, useSSL=False):
		self.target = target
		self.port = port
		self.serveMode = serveMode
		self.dirCreated = False
		self.useSSL = useSSL
		self.cert = self.key = None
		self.auth = None
		self.maxUploadSize = 0
		self.listenIPv4 = True
		self.listenIPv6 = True

		if self.serveMode not in range(self._NUM_MODES):
			self.serveMode = None
			raise ValueError("Unknown serve mode, needs to be MODE_SINGLE, MODE_SINGLETAR, MODE_UPLOAD or MODE_DIRLIST.")

	def setIPv4(self, ipv4):
		""" En- or disable ipv4 """
		self.listenIPv4 = ipv4

	def setIPv6(self, ipv6):
		""" En- or disable ipv6 """
		self.listenIPv6 = ipv6

	def getIPs(self):
		""" Get IPs from all interfaces via ip or ifconfig. """
		# ip and ifconfig sometimes are located in /sbin/
		os.environ['PATH'] += ':/sbin:/usr/sbin'
		proc = Popen(r"ip addr|" + \
					  "sed -n -e 's/.*inet6\{0,1\} \([0-9.a-fA-F:]\+\).*/\\1/ p'|" + \
					  "grep -v '^fe80\|^127.0.0.1\|^::1'", \
					  shell=True, stdout=PIPE, stderr=PIPE)
		if proc.wait() != 0:
			# ip failed somehow, falling back to ifconfig
			oldLang = os.environ.get("LC_ALL", None)
			os.environ['LC_ALL'] = "C"
			proc = Popen(r"ifconfig|" + \
						  "sed -n 's/.*inet6\{0,1\}\( addr:\)\{0,1\} \{0,1\}\([0-9a-fA-F.:]*\).*/" + \
						  "\\2/p'|" + \
						  "grep -v '^fe80\|^127.0.0.1\|^::1'", \
						  shell=True, stdout=PIPE, stderr=PIPE)
			if oldLang:
				os.environ['LC_ALL'] = oldLang
			else:
				del(os.environ['LC_ALL'])
			if proc.wait() != 0:
				# we couldn't find any ip address
				proc = None
		if proc:
			ips = proc.stdout.read().strip().split("\n")

			# filter out ips we are not listening on
			if not self.listenIPv6:
				ips = filter(lambda ip: ":" not in ip, ips)
			if not self.listenIPv4:
				ips = filter(lambda ip: "." not in ip, ips)

			return ips
		return None

	def setSSLKeys(self, cert, key):
		""" Set SSL cert/key. Can be either path to file or pyssl X509/PKey object. """
		self.cert = cert
		self.key = key

	def setMaxUploadSize(self, limit):
		""" Set the maximum upload size in byte """
		self.maxUploadSize = limit

	def setCompression(self, compression):
		""" Set the compression of TarFileHandler """
		if self.serveMode != self.MODE_SINGLETAR:
			raise ServeFileException("Compression mode can only be set in tar-mode.")
		if compression not in TarFileHandler.compressionMethods:
			raise ServeFileException("Compression mode not available.")
		TarFileHandler.compression = compression

	def genKeyPair(self):
		print("Generating SSL certificate...", end="")
		sys.stdout.flush()

		pkey = crypto.PKey()
		pkey.generate_key(crypto.TYPE_RSA, 2048)

		req = crypto.X509Req()
		subj = req.get_subject()
		subj.CN = "127.0.0.1"
		subj.O = "servefile laboratories"
		subj.OU = "servefile"

		# generate altnames
		altNames = []
		for ip in self.getIPs() + ["127.0.0.1", "::1"]:
			altNames.append("IP:%s" % ip)
		altNames.append("DNS:localhost")
		ext = crypto.X509Extension("subjectAltName", False, ",".join(altNames))
		req.add_extensions([ext])

		req.set_pubkey(pkey)
		req.sign(pkey, "sha1")

		cert = crypto.X509()
		# some browsers complain if they see a cert from the same authority
		# with the same serial ==> we just use the seconds as serial.
		cert.set_serial_number(int(time.time()))
		cert.gmtime_adj_notBefore(0)
		cert.gmtime_adj_notAfter(365*24*60*60)
		cert.set_issuer(req.get_subject())
		cert.set_subject(req.get_subject())
		cert.add_extensions([ext])
		cert.set_pubkey(req.get_pubkey())
		cert.sign(pkey, "sha1")

		self.cert = cert
		self.key = pkey

		print("done.")
		print("SHA1 fingerprint:", cert.digest("sha1"))
		print("MD5  fingerprint:", cert.digest("md5"))

	def _getCert(self):
		return self.cert

	def _getKey(self):
		return self.key

	def setAuth(self, user, password, realm=None):
		if not user or not password:
			raise ServeFileException("User and password both need to be at least one character.")
		self.auth = base64.b64encode("%s:%s" % (user, password))
		self.authrealm = realm

	def _createServer(self, handler, withv6=False):
		ThreadedHTTPServer.address_family = socket.AF_INET
		SecureThreadedHTTPServer.address_family = socket.AF_INET
		listenIp = ''
		server = None

		if withv6:
			listenIp = '::'
			ThreadedHTTPServer.address_family = socket.AF_INET6
			SecureThreadedHTTPServer.address_family = socket.AF_INET6

		if self.useSSL:
			if not self._getKey():
				self.genKeyPair()
			try:
				server = SecureThreadedHTTPServer(self._getCert(), self._getKey(),
									(listenIp, self.port), handler, bind_and_activate=False)
			except SSL.Error as e:
				raise ServeFileException("SSL error: Could not read SSL public/private key from file(s) (error was: \"%s\")" % (e[0][0][2],))
		else:
			server = ThreadedHTTPServer((listenIp, self.port), handler,
												bind_and_activate=False)

		if withv6:
			server.socket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1)

		server.server_bind()
		server.server_activate()

		return server

	def serve(self):
		self.handler = self._confAndFindHandler()
		self.server = []

		try:
			currsocktype = "IPv4"
			if self.listenIPv4:
				self.server.append(self._createServer(self.handler))
			currsocktype = "IPv6"
			if self.listenIPv6:
				self.server.append(self._createServer(self.handler, withv6=True))
		except socket.error as e:
			raise ServeFileException("Could not open %s socket: %s" % (currsocktype, e))

		if self.serveMode != self.MODE_UPLOAD:
			print("Serving \"%s\" at port %d." % (self.target, self.port))
		else:
			print("Serving \"%s\" for uploads at port %d." % (self.target, self.port))

		# print urls with local network adresses
		print("\nSome addresses %s will be available at:" % \
				("this file" if (self.serveMode != self.MODE_UPLOAD) else "the uploadform", ))
		ips = self.getIPs()
		if not ips or len(ips) == 0 or ips[0] == '':
			print("Could not find any addresses.")
		else:
			for ip in ips:
				if ":" in ip:
					ip = "[%s]" % ip
				print("\thttp%s://%s:%d/" % (self.useSSL and "s" or "", ip, self.port))
		print()

		try:
			while True:
				(servers, _, _) = select.select(self.server, [], [])
				for server in servers:
					server.handle_request()
		except KeyboardInterrupt:
			for server in self.server:
				server.socket.close()

		# cleanup potential upload directory
		if self.dirCreated and len(os.listdir(self.target)) == 0:
			# created upload dir was not used
			os.rmdir(self.target)

	def _confAndFindHandler(self):
		handler = None
		if self.serveMode == self.MODE_SINGLE:
			try:
				testit = open(self.target, 'r')
				testit.close()
			except IOError:
				raise ServeFileException("Error: Could not open file!")
			FileHandler.filePath = self.target
			FileHandler.fileName = os.path.basename(self.target)
			FileHandler.fileLength = os.stat(self.target).st_size
			handler = FileHandler
		elif self.serveMode == self.MODE_SINGLETAR:
			self.realTarget = os.path.realpath(self.target)
			if not os.path.exists(self.realTarget):
				raise ServeFileException("Error: Could not open file or directory.")
			TarFileHandler.target = self.realTarget
			TarFileHandler.fileName = os.path.basename(self.realTarget.rstrip("/")) + TarFileHandler.getCompressionExt()

			handler = TarFileHandler
		elif self.serveMode == self.MODE_UPLOAD:
			if os.path.isdir(self.target):
				print("Warning: Uploading to an already existing directory.")
			elif not os.path.exists(self.target):
				self.dirCreated = True
				try:
					os.mkdir(self.target)
				except (IOError, OSError):
					raise ServeFileException("Error: Could not create directory '%s' for uploads." % (self.target,))
			else:
				raise ServeFileException("Error: Upload directory already exists and is a file.")
			FilePutter.targetDir = self.target
			FilePutter.maxUploadSize = self.maxUploadSize
			handler = FilePutter
		elif self.serveMode == self.MODE_LISTDIR:
			if not os.path.exists(self.target):
				raise ServeFileException("Error: Could not open file or directory.")
			if not os.path.isdir(self.target):
				raise ServeFileException("Error: '%s' is not a directory." % (self.target,))
			handler = DirListingHandler
			handler.targetDir = self.target

		if self.auth:
			# do authentication
			AuthenticationHandler.authString = self.auth
			if self.authrealm:
				AuthenticationHandler.realm = self.authrealm
			class AuthenticatedHandler(AuthenticationHandler, handler):
				pass
			handler = AuthenticatedHandler

		if self.useSSL:
			# secure handler
			@catchSSLErrors
			class AlreadySecuredHandler(SecureHandler, handler):
				pass
			handler = AlreadySecuredHandler
		return handler


class AuthenticationHandler():
	# base64 encoded user:password string for authentication
	authString = None
	realm = "Restricted area"

	def handle_one_request(self):
		""" Overloaded function to handle one request.

		Before calling the responsible do_METHOD function, check credentials
		"""
		self.raw_requestline = self.rfile.readline()
		if not self.raw_requestline:
			self.close_connection = 1
			return
		if not self.parse_request(): # An error code has been sent, just exit
			return

		authorized = False
		if "Authorization" in self.headers:
			if self.headers["Authorization"] == ("Basic " + self.authString):
				authorized = True
		if authorized:
			mname = 'do_' + self.command
			if not hasattr(self, mname):
				self.send_error(501, "Unsupported method (%r)" % self.command)
				return
			method = getattr(self, mname)
			method()
		else:
			self.send_response(401)
			self.send_header("WWW-Authenticate", "Basic realm=\"%s\"" % self.realm)


def main():
	parser = argparse.ArgumentParser(description='Serve a single file via HTTP.')
	parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
	parser.add_argument('target', metavar='file/directory', type=str)
	parser.add_argument('-p', '--port', type=int, default=8080, \
	                    help='Port to listen on')
	parser.add_argument('-u', '--upload', action="store_true", default=False, \
	                    help="Enable uploads to a given directory")
	parser.add_argument('-s', '--max-upload-size', type=str, \
	                    help="Limit upload size in kB. Size modifiers are allowed, e.g. 2G, 12MB, 1B")
	parser.add_argument('-l', '--list-dir', action="store_true", default=False, \
	                    help="Show directory indexes and allow access to all subdirectories")
	parser.add_argument('--ssl', action="store_true", default=False, \
	                    help="Enable SSL. If no key/cert is specified one will be generated")
	parser.add_argument('--key', type=str, \
	                    help="Keyfile to use for SSL. If no cert is given with --cert the keyfile will also be searched for a cert")
	parser.add_argument('--cert', type=str, \
	                    help="Certfile to use for SSL")
	parser.add_argument('-a', '--auth', type=str, metavar='user:password', \
	                    help="Set user and password for HTTP basic authentication")
	parser.add_argument('--realm', type=str, default=None,\
	                    help="Set a realm for HTTP basic authentication")
	parser.add_argument('-t', '--tar', action="store_true", default=False, \
	                    help="Enable on the fly tar creation for given file or directory. Note: Download continuation will not be available")
	parser.add_argument('-c', '--compression', type=str, metavar='method', \
	                    default="none", \
	                    help="Set compression method, only in combination with --tar. Can be one of %s" % ", ".join(TarFileHandler.compressionMethods))
	parser.add_argument('-4', '--ipv4-only', action="store_true", default=False, \
	                    help="Listen on IPv4 only")
	parser.add_argument('-6', '--ipv6-only', action="store_true", default=False, \
	                    help="Listen on IPv6 only")

	args = parser.parse_args()
	maxUploadSize = 0

	# check for invalid option combinations/preparse stuff
	if args.max_upload_size and not args.upload:
		print("Error: Maximum upload size can only be specified when in upload mode.")
		sys.exit(1)

	if args.upload and args.list_dir:
		print("Error: Upload and dirlisting can't be enabled together.")
		sys.exit(1)

	if args.max_upload_size:
		sizeRe = re.match("^(\d+(?:[,.]\d+)?)(?:([bkmgtpe])(?:(?<!b)b?)?)?$", args.max_upload_size.lower())
		if not sizeRe:
			print("Error: Your max upload size param is broken. Try something like 3M or 2.5Gb.")
			sys.exit(1)
		uploadSize, modifier = sizeRe.groups()
		uploadSize = float(uploadSize.replace(",", "."))
		sizes = ["b", "k", "m", "g", "t", "p", "e"]
		maxUploadSize = int(uploadSize * pow(1024, sizes.index(modifier or "k")))
		if maxUploadSize < 0:
			print("Error: Your max upload size can't be negative")
			sys.exit(1)

	if args.ssl and not HAVE_SSL:
		print("Error: SSL is not available, please install pyssl (python-openssl).")
		sys.exit(1)

	if args.cert and not args.key:
		print("Error: Please specify a key along with your cert.")
		sys.exit(1)

	if not args.ssl and (args.cert or args.key):
		print("Error: You need to enable ssl with --ssl when specifying certs/keys.")
		sys.exit(1)

	if args.auth:
		dpos = args.auth.find(":")
		if dpos <= 0 or dpos == (len(args.auth)-1):
			print("Error: User and password for HTTP basic authentication need to be both at least one character and have to be separated by a \":\".")
			sys.exit(1)

	if args.realm and not args.auth:
		print("You can only specify a realm when HTTP basic authentication is enabled.")
		sys.exit(1)

	if args.compression != "none" and not args.tar:
		print("Error: Please use --tar if you want to tar everything.")
		sys.exit(1)

	if args.tar and args.upload:
		print("Error: --tar mode will not work with uploads.")
		sys.exit(1)

	if args.tar and args.list_dir:
		print("Error: --tar mode will not work with directory listings.")
		sys.exit(1)

	compression = None
	if args.compression:
		if args.compression in TarFileHandler.compressionMethods:
			compression = args.compression
		else:
			print("Error: Compression mode '%s' is unknown." % args.compression)
			sys.exit(1)

	if args.ipv4_only and args.ipv6_only:
		print("You can't listen both on IPv4 and IPv6 \"only\".")
		sys.exit(1)

	if args.ipv6_only and not socket.has_ipv6:
		print("Your system does not support IPv6.")
		sys.exit(1)

	mode = None
	if args.upload:
		mode = ServeFile.MODE_UPLOAD
	elif args.list_dir:
		mode = ServeFile.MODE_LISTDIR
	elif args.tar:
		mode = ServeFile.MODE_SINGLETAR
	else:
		mode = ServeFile.MODE_SINGLE

	server = None
	try:
		server = ServeFile(args.target, args.port, mode, args.ssl)
		if maxUploadSize > 0:
			server.setMaxUploadSize(maxUploadSize)
		if args.ssl and args.key:
			cert = args.cert or args.key
			server.setSSLKeys(cert, args.key)
		if args.auth:
			user, password = args.auth.split(":", 1)
			server.setAuth(user, password, args.realm)
		if compression and compression != "none":
			server.setCompression(compression)
		if args.ipv4_only or not socket.has_ipv6:
			server.setIPv6(False)
		if args.ipv6_only:
			server.setIPv4(False)
		server.serve()
	except ServeFileException as e:
		print(e)
		sys.exit(1)
	print("Good bye.")


if __name__ == '__main__':
	main()

