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#

#

# 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.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""HTTP server module.

"""

import socket

import BaseHTTPServer

import OpenSSL

import time

import logging

from ganeti import logger

from ganeti import serializer

class HTTPException(Exception):

  code = None

  message = None

  def __init__(self, message=None):

    if message is not None:

      self.message = message

class HTTPBadRequest(HTTPException):

  code = 400

class HTTPForbidden(HTTPException):

  code = 403

class HTTPNotFound(HTTPException):

  code = 404

class HTTPGone(HTTPException):

  code = 410

class HTTPLengthRequired(HTTPException):

  code = 411

class HTTPInternalError(HTTPException):

  code = 500

class HTTPNotImplemented(HTTPException):

  code = 501

class HTTPServiceUnavailable(HTTPException):

  code = 503

class ApacheLogfile:

  """Utility class to write HTTP server log files.

  The written format is the "Common Log Format" as defined by Apache:

  http://httpd.apache.org/docs/2.2/mod/mod_log_config.html#examples

  """

  MONTHNAME = [None,

               'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',

               'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

  def __init__(self, fd):

    """Constructor for ApacheLogfile class.

    Args:

    - fd: Open file object

    """

    self._fd = fd

  def LogRequest(self, request, format, *args):

    self._fd.write("%s %s %s [%s] %s\n" % (

      # Remote host address

      request.address_string(),

      # RFC1413 identity (identd)

      "-",

      # Remote user

      "-",

      # Request time

      self._FormatCurrentTime(),

      # Message

      format % args,

      ))

    self._fd.flush()

  def _FormatCurrentTime(self):

    """Formats current time in Common Log Format.

    """

    return self._FormatLogTime(time.time())

  def _FormatLogTime(self, seconds):

    """Formats time for Common Log Format.

    All timestamps are logged in the UTC timezone.

    Args:

    - seconds: Time in seconds since the epoch

    """

    (_, month, _, _, _, _, _, _, _) = tm = time.gmtime(seconds)

    format = "%d/" + self.MONTHNAME[month] + "/%Y:%H:%M:%S +0000"

    return time.strftime(format, tm)

class HTTPServer(BaseHTTPServer.HTTPServer, object):

  """Class to provide an HTTP/HTTPS server.

  """

  allow_reuse_address = True

  def __init__(self, server_address, HandlerClass, httplog=None,

               enable_ssl=False, ssl_key=None, ssl_cert=None):

    """Server constructor.

    Args:

      server_address: a touple containing:

        ip: a string with IP address, localhost if empty string

        port: port number, integer

      HandlerClass: HTTPRequestHandler object

      httplog: Access log object

      enable_ssl: Whether to enable SSL

      ssl_key: SSL key file

      ssl_cert: SSL certificate key

    """

    BaseHTTPServer.HTTPServer.__init__(self, server_address, HandlerClass)

    self.httplog = httplog

    if enable_ssl:

      # Set up SSL

      context = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD)

      context.use_privatekey_file(ssl_key)

      context.use_certificate_file(ssl_cert)

      self.socket = OpenSSL.SSL.Connection(context,

                                           socket.socket(self.address_family,

                                           self.socket_type))

    else:

      self.socket = socket.socket(self.address_family, self.socket_type)

    self.server_bind()

    self.server_activate()

class HTTPJsonConverter:

  CONTENT_TYPE = "application/json"

  def Encode(self, data):

    return serializer.DumpJson(data)

  def Decode(self, data):

    return serializer.LoadJson(data)

class HTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler, object):

  """Request handler class.

  """

  def setup(self):

    """Setup secure read and write file objects.

    """

    self.connection = self.request

    self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)

    self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)

  def handle_one_request(self):

    """Parses a request and calls the handler function.

    """

    self.raw_requestline = None

    try:

      self.raw_requestline = self.rfile.readline()

    except OpenSSL.SSL.Error, ex:

      logger.Error("Error in SSL: %s" % str(ex))

    if not self.raw_requestline:

      self.close_connection = 1

      return

    if not self.parse_request(): # An error code has been sent, just exit

      return

    logging.debug("HTTP request: %s", self.raw_requestline.rstrip("\r\n"))

    try:

      self._ReadPostData()

      result = self.HandleRequest()

      # TODO: Content-type

      encoder = HTTPJsonConverter()

      encoded_result = encoder.Encode(result)

      self.send_response(200)

      self.send_header("Content-Type", encoder.CONTENT_TYPE)

      self.send_header("Content-Length", str(len(encoded_result)))

      self.end_headers()

      self.wfile.write(encoded_result)

    except HTTPException, err:

      self.send_error(err.code, message=err.message)

    except Exception, err:

      self.send_error(HTTPInternalError.code, message=str(err))

    except:

      self.send_error(HTTPInternalError.code, message="Unknown error")

  def _ReadPostData(self):

    if self.command.upper() not in ("POST", "PUT"):

      self.post_data = None

      return

    # TODO: Decide what to do when Content-Length header was not sent

    try:

      content_length = int(self.headers.get('Content-Length', 0))

    except ValueError:

      raise HTTPBadRequest("No Content-Length header or invalid format")

    try:

      data = self.rfile.read(content_length)

    except socket.error, err:

      logger.Error("Socket error while reading: %s" % str(err))

      return

    # TODO: Content-type, error handling

    self.post_data = HTTPJsonConverter().Decode(data)

    logging.debug("HTTP POST data: %s", self.post_data)

  def HandleRequest(self):

    """Handles a request.

    """

    raise NotImplementedError()

  def log_message(self, format, *args):

    """Log an arbitrary message.

    This is used by all other logging functions.

    The first argument, FORMAT, is a format string for the

    message to be logged.  If the format string contains

    any % escapes requiring parameters, they should be

    specified as subsequent arguments (it's just like

    printf!).

    """

    logging.debug("Handled request: %s", format % args)

    if self.server.httplog:

      self.server.httplog.LogRequest(self, format, *args)