#!/usr/bin/env python
# -*- encoding: utf-8 -*-
#
#  Copyright (C) 2004 Simon Budig  <simon@budig.de>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 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 General Public License for more details.
#
#  A copy of the GNU General Public License is available at
#  http://www.fsf.org/licenses/gpl.txt, you can also write to the
#  Free Software  Foundation, Inc., 59 Temple Place - Suite 330,
#  Boston, MA 02111-1307, USA.

# Darwin support with the help from Mat Caughron, <mat@phpconsulting.com>
# Solaris support by Colin Marquardt, <colin.marquardt@zmd.de>
# FreeBSD support with the help from Andy Gimblett, <A.M.Gimblett@swansea.ac.uk>
# Cygwin support by Stefan Reichör <stefan@xsteve.at>
# NetBSD support by Geoffroy Weisenhorn, <geoffroy.weisenhorn@gmail.com>

""" woof -- an ad-hoc single file webserver"""

import sys, os, popen2, signal, select, socket, getopt, commands
import stat
import urllib, BaseHTTPServer
import ConfigParser

maxdownloads = 1
CPID = -1
COMPRESSED = True
IPV6 = False

def find_ip ():
    """
    Utility function to guess the IP (as a string) where the server can be
    reached from the outside. Quite nasty problem actually.
    """

    if sys.platform == "cygwin":
        ipcfg = os.popen("ipconfig").readlines()
        for aline in ipcfg:
            try:
                candidat = aline.split(":")[1].strip()
                if candidat[0].isdigit():
                    break
            except:
                pass
        return candidat

    os.environ["PATH"] = "/sbin:/usr/sbin:/usr/local/sbin:" + os.environ["PATH"]
    platform = os.uname()[0]
    if platform == "Linux":
        netstat = commands.getoutput ("LC_MESSAGES=C netstat -rn")
        defiface = [i.split ()[-1] for i in netstat.split('\n')
                                    if i.split()[0] == "0.0.0.0"]
    elif platform in ("Darwin", "FreeBSD"):
        netstat = commands.getoutput ("LC_MESSAGES=C netstat -rn")
        defiface = [i.split ()[-1] for i in netstat.split('\n')
                    if len(i) > 2 and i.split()[0] == "default"]
    elif platform == "SunOS":
        netstat = commands.getoutput ("LC_MESSAGES=C netstat -arn")
        defiface = [i.split ()[-1] for i in netstat.split('\n')
                    if len(i) > 2 and i.split()[0] == "0.0.0.0"]
    elif platform == "NetBSD":
        netstat = commands.getoutput ("LC_MESSAGES=C netstat -arn")
        defiface = [i.split()[-1] for i in netstat.split('\n')
                    if len(i) > 2 and i.split()[0] == "default"]
    else:
        print >> sys.stderr, "Unsupported platform; \
              please add support for your platform in find_ip()."
        return None

    if not defiface:
        return None

    if platform == "Linux":
        if IPV6:
            spliter = "inet6 addr:"
        else:
            spliter = "inet addr:"
        ifcfg = commands.getoutput ("LC_MESSAGES=C ifconfig "
                                  + defiface[0]).split (spliter)
    elif platform in ("Darwin", "FreeBSD", "SunOS", "NetBSD"):
        ifcfg = commands.getoutput ("LC_MESSAGES=C ifconfig "
                                  + defiface[0]).split ("inet ")

    if IPV6:
        ifcfg_len = 3
    else:
        ifcfg_len = 2

    if len (ifcfg) != ifcfg_len:
        return None
    ip_addr = ifcfg[1].split ()[0]

    if IPV6:
        ip_addr = ip_addr.split('/')[0]
    else:
    # sanity check, only for ipv4 at the moment
        try:
            ints = [ i for i in ip_addr.split (".") if 0 <= int(i) <= 255]
            if len (ints) != 4:
                return None
        except ValueError:
            return None

    return ip_addr

def is_owner(stf):
    """Return true if the file belongs to the current user"""
    return stf.st_uid == os.getuid()

def is_group(stf):
    """Return true if the file belongs to the group of current user"""
    return stf.st_gid == os.getgid()

def is_read(filename):
    """ Check whether a file is readable """
    result_st = os.stat(filename)
    if is_owner(result_st):
        return (result_st.st_mode & stat.S_IRUSR)
    elif is_group(result_st):
        return (result_st.st_mode & stat.S_IRGRP)
    else:
        return (result_st.st_mode & stat.S_IROTH)

class FileServHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    """
    Main class implementing an HTTP-Requesthandler, that serves just a single
    file and redirects all other requests to this file (this passes the actual
    filename to the client).
    Currently it is impossible to serve different files with different
    instances of this class.
    """
    server_version = "Simons FileServer"
    protocol_version = "HTTP/1.0"
    filename = "."

    def log_request(self, code='-', size='-'):
        """Log an accepted request."""
        if code == 200:
            BaseHTTPServer.BaseHTTPRequestHandler.log_request(self, code, size)

    def do_GET(self):
        """
        Redirect any request to the filename of the file to serve.
        This hands over the filename to the client.
        """
        global maxdownloads, CPID, COMPRESSED
        self.path = urllib.quote(urllib.unquote(self.path))
        location = "/" + urllib.quote(os.path.basename(self.filename))
        if os.path.isdir(self.filename):
            if COMPRESSED:
                location += ".tar.gz"
            else:
                location += ".tar"

        if self.path != location:
            txt = """\
            <html>
                <head><title>302 Found</title></head>
                <body>302 Found <a href="%s">here</a>.</body>
            </html>\n""" % location
            self.send_response (302)
            self.send_header ("Location", location)
            self.send_header ("Content-type", "text/html")
            self.send_header ("Content-Length", str (len (txt)))
            self.end_headers ()
            self.wfile.write (txt)
            return

        maxdownloads -= 1

        # let a separate process handle the actual download, so that
        # multiple downloads can happen simultaneously.

        CPID = os.fork()
        os.setpgrp()

        if CPID == 0:
            # Child process
            size = -1
            datafile = None
            child = None

            if os.path.isfile (self.filename):
                size = os.path.getsize (self.filename)
                datafile = open (self.filename)
            elif os.path.isdir (self.filename):
                filepath = os.path.split(self.filename)
                os.environ['woof_dir'], os.environ['woof_file'] = filepath
                if COMPRESSED:
                    arg = 'z'
                else:
                    arg = ''
                tarcmd = 'cd "$woof_dir";tar c%sf - "$woof_file"'
                child = popen2.Popen3(tarcmd % arg)
                datafile = child.fromchild

            self.send_response (200)
            self.send_header ("Content-type", "application/octet-stream")
            if size >= 0:
                self.send_header ("Content-Length", size)
            self.end_headers ()
            try:
                try:
                    while 1:
                        if select.select ([datafile], [], [], 2)[0]:
                            chunk = datafile.read(1024)
                            if chunk:
                                self.wfile.write(chunk)
                            else:
                                datafile.close()
                                print '%s - - [%s] "%s %s %s" Complete -' % (
                                    self.client_address[0],
                                    self.log_date_time_string(),
                                    self.command,
                                    self.path,
                                    self.request_version)
                                break
                except:
                    print >> sys.stderr, "Connection broke. Aborting"

            finally:
                # for some reason tar doesnt stop working when the pipe breaks
                if child:
                    if child.poll ():
                        os.killpg (os.getpgid (child.pid), signal.SIGTERM)

def serve_files (filename, maxdown = 1, ip_addr = '', port = 8080):
    """
    Launch HTTP server
    """
    global maxdownloads, IPV6
    maxdownloads = maxdown
    # We have to somehow push the filename of the file to serve to the
    # class handling the requests. This is an evil way to do this...

    FileServHTTPRequestHandler.filename = filename

    if IPV6:
        BaseHTTPServer.HTTPServer.address_family = socket.AF_INET6

    try:
        httpd = BaseHTTPServer.HTTPServer ((ip_addr, port),
                                          FileServHTTPRequestHandler)
    except socket.error:
        print >> sys.stderr, ("cannot bind to port %d" % (port))
        sys.exit (1)

    if not ip_addr:
        ip_addr = find_ip ()
        ip_addr = IPV6 and '[%s]' % ip_addr or ip_addr
    if ip_addr:
        print "Now serving on http://%s:%s/" % (ip_addr, httpd.server_port)

    while CPID != 0 and maxdownloads > 0:
        httpd.handle_request ()

def usage (defport, defmaxdown, errmsg = None):
    """
    Display usage message
    """
    name = os.path.basename (sys.argv[0])
    print >> sys.stderr, """
    Usage: %s [-i <ip_addr>] [-p <port>] [-c <count>] [-u] [-6] <file/dir>
           %s [-i <ip_addr>] [-p <port>] [-c <count>] [-u] [-6] -s

    Serves a single file <count> times via http on port <port> on IP
    address <ip_addr>.
    When a directory is specified, a .tar.gz archive gets served (or an
    uncompressed tar archive when -u is specified), when -s is specified
    instead of a filename, %s distributes itself.

    defaults: count = %d, port = %d

    You can specify different defaults in two locations: /etc/woofrc
    and ~/.woofrc can be INI-style config files containing the default
    port and the default count. The file in the home directory takes
    precedence.

    Sample file:

        [main]
        port = 8008
        count = 2
        ip = 127.0.0.1
        compressed = true
        ipv6 = false
    """ % (name, name, name, defmaxdown, defport)
    if errmsg:
        print >> sys.stderr, errmsg
        print >> sys.stderr
    sys.exit (1)

def main ():
    """
    parse config file or options before launching
    the http server
    """

    global CPID, COMPRESSED, IPV6

    maxdown = 1
    port = 8080
    ip_addr = ''

    config = ConfigParser.ConfigParser()
    config.read (['/etc/woofrc', os.path.expanduser('~/.woofrc')])

    if config.has_option ('main', 'port'):
        port = config.getint ('main', 'port')

    if config.has_option ('main', 'count'):
        maxdown = config.getint ('main', 'count')

    if config.has_option ('main', 'ip'):
        ip_addr = config.get ('main', 'ip')

    if config.has_option ('main', 'compressed'):
        COMPRESSED = config.getboolean ('main', 'compressed')

    if config.has_option ('main', 'ipv6'):
        IPV6 = config.getboolean ('main', 'ipv6')

    defaultport = port
    defaultmaxdown = maxdown

    try:
        options, filenames = getopt.getopt (sys.argv[1:], "h6sui:c:p:")
    except getopt.GetoptError, desc:
        usage (defaultport, defaultmaxdown, desc)

    for option, val in options:
        if option == '-c':
            try:
                maxdown = int (val)
                if maxdown <= 0:
                    raise ValueError
            except ValueError:
                usage (defaultport, defaultmaxdown,
                       "invalid download count: %r. "
                       "Please specify an integer >= 0." % val)
        elif option == '-i':
            ip_addr = val
        elif option == '-p':
            try:
                port = int (val)
            except ValueError:
                usage (defaultport, defaultmaxdown,"Invalid port number: %r.\
                Please specify an integer" % val)
        elif option == '-s':
            filenames.append (__file__)
        elif option == '-h':
            usage (defaultport, defaultmaxdown)
        elif option == '-u':
            COMPRESSED = False
        elif option == '-6':
            IPV6 = True
        else:
            usage (defaultport, defaultmaxdown, "Unknown option: %r" % option)

    if len (filenames) == 1:
        filename = os.path.abspath (filenames[0])
    else:
        usage (defaultport, defaultmaxdown,
               "Can only serve single files/directories.")
    if not os.path.exists (filename):
        usage (defaultport, defaultmaxdown,
             "%s: No such file or directory" % filenames[0])
    if not (os.path.isfile (filename) or os.path.isdir (filename)):
        usage (defaultport, defaultmaxdown,
             "%s: Neither file nor directory" % filenames[0])
    if not is_read(filename):
        usage (defaultport, defaultmaxdown,
               "%s: Check read permission" % filenames[0])
    if IPV6:
        ip_addr = ''

    serve_files (filename, maxdown, ip_addr, port)

    # wait for child processes to terminate
    if CPID != 0:
        try:
            while 1:
                os.wait ()
        except OSError:
            pass

if __name__ == '__main__':
    try:
        main ()
    except KeyboardInterrupt:
        print >> sys.stderr, "Interrupted .."