#!/usr/bin/env python
#coding=utf-8
"""
Author:         Xia Kai <xiaket@corp.netease.com/xiaket@gmail.com>
Filename:       httpd.py
Type:           httpd that support resume.
Last modified:  2011-06-27 17:38

Description:
"""
import os
import socket
import sys

from random import randint
from BaseHTTPServer import HTTPServer
from SimpleHTTPServer import SimpleHTTPRequestHandler


class NotracebackServer(HTTPServer):
    """
    could make this a mixin, but decide to keep it simple for a simple script.
    """
    def handle_error(self, *args):
        """override default function to disable traceback."""
        pass


class PartialContentHandler(SimpleHTTPRequestHandler):
    def mycopy(self, f):
        """
        This would do the actual file tranfer. if client terminated transfer,
        we would log it.
        """
        try:
            self.copyfile(f, self.wfile)
            self.log_message('"%s" %s', self.requestline, "req finished.")
        except socket.error:
            self.log_message('"%s" %s', self.requestline, "req terminated.")
        finally:
            f.close()
        return None

    def do_GET(self):
        """Serve a GET request."""
        f = self.send_head()
        if f:
            self.mycopy(f)

    def send_head(self):
        """
        added support for partial content. i'm not surprised if http HEAD
        method would fail.
        """
        path = self.translate_path(self.path)
        f = None
        if os.path.isdir(path):
            # oh, we do not support directory listing.
            self.send_error(404, "File not found")
            return None

        ctype = self.guess_type(path)
        try:
            f = open(path, 'rb')
        except IOError:
            self.send_error(404, "File not found")
            return None
        if self.headers.get("Range"):
            # partial content all treated here.
            # we do not support If-Range request.
            # range could only be of the form:
            #   Range: bytes=9855420-
            start = self.headers.get("Range")
            try:
                pos = int(start[6:-1])
            except ValueError:
                self.send_error(400, "bad range specified.")
                f.close()
                return None

            self.send_response(206)
            self.send_header("Content-type", ctype)
            self.send_header("Connection", "keep-alive")
            fs = os.fstat(f.fileno())
            full = fs.st_size
            self.send_header("Content-Length", str(fs[6] - pos))
            self.send_header("Last-Modified", self.date_time_string(fs.st_mtime))
            start = start.replace("=", " ")
            self.send_header("Content-Range", "%s%s/%s" % (start, full-1, full))
            self.end_headers()
            f.seek(pos)
            self.mycopy(f)
            return None

        self.send_response(200)
        self.send_header("Content-type", ctype)
        fs = os.fstat(f.fileno())
        self.send_header("Content-Length", str(fs[6]))
        self.send_header("Last-Modified", self.date_time_string(fs.st_mtime))
        self.end_headers()
        return f


def main(port, server_class=NotracebackServer,
        handler_class=PartialContentHandler):
    server_address = ('', port)
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()


if __name__ == "__main__":
    port = randint(20000, 50000)
    ip = socket.gethostbyname(socket.gethostname())
    print "serving on: http://%s:%s/" % (ip, port)
    print "===== local files ====="
    cwd = os.getcwd()
    for f in os.listdir(cwd):
        if f == sys.argv[0] or f.startswith("."):
            continue
        fullpath = os.path.join(cwd, f)
        if os.path.isfile(fullpath):
            print "link: http://%s:%s/%s" % (ip, port, f)
    print "===== start logging =====\n"
    main(port=port)