wget/testenv/server/http/http_server.py

from http.server import HTTPServer, BaseHTTPRequestHandler
from socketserver import BaseServer
from posixpath import basename, splitext
from base64 import b64encode
from random import random
from hashlib import md5
import threading
import socket
import re
import ssl
import os


class InvalidRangeHeader (Exception):

    """ Create an Exception for handling of invalid Range Headers. """
    # TODO: Eliminate this exception and use only ServerError

    def __init__ (self, err_message):
        self.err_message = err_message

class ServerError (Exception):
    def __init__ (self, err_message):
        self.err_message = err_message


class StoppableHTTPServer (HTTPServer):

    request_headers = list ()

    """ Define methods for configuring the Server. """

    def server_conf (self, filelist, conf_dict):
        """ Set Server Rules and File System for this instance. """
        self.server_configs = conf_dict
        self.fileSys = filelist

    def get_req_headers (self):
        return self.request_headers

class HTTPSServer (StoppableHTTPServer):

   def __init__ (self, address, handler):
         BaseServer.__init__ (self, address, handler)
         print (os.getcwd())
         CERTFILE = os.path.abspath (os.path.join ('..', 'certs', 'wget-cert.pem'))
         print (CERTFILE)
         fop = open (CERTFILE)
         print (fop.readline())
         self.socket = ssl.wrap_socket (
               sock = socket.socket (self.address_family, self.socket_type),
               ssl_version = ssl.PROTOCOL_TLSv1,
               certfile = CERTFILE,
               server_side = True
               )
         self.server_bind ()
         self.server_activate ()

class WgetHTTPRequestHandler (BaseHTTPRequestHandler):

    """ Define methods for handling Test Checks. """

    def get_rule_list (self, name):
        r_list = self.rules.get (name) if name in self.rules else None
        return r_list


class _Handler (WgetHTTPRequestHandler):

    """ Define Handler Methods for different Requests. """

    InvalidRangeHeader = InvalidRangeHeader
    protocol_version = 'HTTP/1.1'

    """ Define functions for various HTTP Requests. """

    def do_HEAD (self):
        self.send_head ("HEAD")

    def do_GET (self):
        content, start = self.send_head ("GET")
        if content:
            if start is None:
                self.wfile.write (content.encode ('utf-8'))
            else:
                self.wfile.write (content.encode ('utf-8')[start:])

    def do_POST (self):
        path = self.path[1:]
        self.rules = self.server.server_configs.get (path)
        if not self.custom_response ():
            return (None, None)
        if path in self.server.fileSys:
            body_data = self.get_body_data ()
            self.send_response (200)
            self.send_header ("Content-type", "text/plain")
            content = self.server.fileSys.pop (path) + "\n" + body_data
            total_length = len (content)
            self.server.fileSys[path] = content
            self.send_header ("Content-Length", total_length)
            self.finish_headers ()
            try:
                self.wfile.write (content.encode ('utf-8'))
            except Exception:
                pass
        else:
            self.send_put (path)

    def do_PUT (self):
        path = self.path[1:]
        self.rules = self.server.server_configs.get (path)
        if not self.custom_response ():
            return (None, None)
        self.server.fileSys.pop (path, None)
        self.send_put (path)

    """ End of HTTP Request Method Handlers. """

    """ Helper functions for the Handlers. """

    def parse_range_header (self, header_line, length):
        if header_line is None:
            return None
        if not header_line.startswith ("bytes="):
            raise InvalidRangeHeader ("Cannot parse header Range: %s" %
                                     (header_line))
        regex = re.match (r"^bytes=(\d*)\-$", header_line)
        range_start = int (regex.group (1))
        if range_start >= length:
            raise InvalidRangeHeader ("Range Overflow")
        return range_start

    def get_body_data (self):
        cLength_header = self.headers.get ("Content-Length")
        cLength = int (cLength_header) if cLength_header is not None else 0
        body_data = self.rfile.read (cLength).decode ('utf-8')
        return body_data

    def send_put (self, path):
        body_data = self.get_body_data ()
        self.send_response (201)
        self.server.fileSys[path] = body_data
        self.send_header ("Content-type", "text/plain")
        self.send_header ("Content-Length", len (body_data))
        self.finish_headers ()
        try:
            self.wfile.write (body_data.encode ('utf-8'))
        except Exception:
            pass

    def SendHeader (self, header_obj):
        pass
#        headers_list = header_obj.headers
#        for header_line in headers_list:
#            print (header_line + " : " + headers_list[header_line])
#            self.send_header (header_line, headers_list[header_line])

    def send_cust_headers (self):
        header_obj = self.get_rule_list ('SendHeader')
        if header_obj:
            for header in header_obj.headers:
                self.send_header (header, header_obj.headers[header])

    def finish_headers (self):
        self.send_cust_headers ()
        self.end_headers ()

    def Response (self, resp_obj):
        self.send_response (resp_obj.response_code)
        self.finish_headers ()
        raise ServerError ("Custom Response code sent.")

    def custom_response (self):
        codes = self.get_rule_list ('Response')
        if codes:
            self.send_response (codes.response_code)
            self.finish_headers ()
            return False
        else:
            return True

    def base64 (self, data):
        string = b64encode (data.encode ('utf-8'))
        return string.decode ('utf-8')

    def send_challenge (self, auth_type):
        if auth_type == "Both":
            self.send_challenge ("Digest")
            self.send_challenge ("Basic")
            return
        if auth_type == "Basic":
            challenge_str = 'Basic realm="Wget-Test"'
        elif auth_type == "Digest" or auth_type == "Both_inline":
            self.nonce = md5 (str (random ()).encode ('utf-8')).hexdigest ()
            self.opaque = md5 (str (random ()).encode ('utf-8')).hexdigest ()
            challenge_str = 'Digest realm="Test", nonce="%s", opaque="%s"' %(
                                                                   self.nonce,
                                                                   self.opaque)
            challenge_str += ', qop="auth"'
            if auth_type == "Both_inline":
                challenge_str = 'Basic realm="Wget-Test", ' + challenge_str
        self.send_header ("WWW-Authenticate", challenge_str)

    def authorize_Basic (self, auth_header, auth_rule):
        if auth_header is None or auth_header.split(' ')[0] != 'Basic':
            return False
        else:
            self.user = auth_rule.auth_user
            self.passw = auth_rule.auth_pass
            auth_str = "Basic " + self.base64 (self.user + ":" + self.passw)
            return True if auth_str == auth_header else False

    def parse_auth_header (self, auth_header):
        n = len("Digest ")
        auth_header = auth_header[n:].strip()
        items = auth_header.split(", ")
        key_values = [i.split("=", 1) for i in items]
        key_values = [(k.strip(), v.strip().replace('"', '')) for k, v in key_values]
        return dict(key_values)

    def KD (self, secret, data):
        return self.H (secret + ":" + data)

    def H (self, data):
        return md5 (data.encode ('utf-8')).hexdigest ()

    def A1 (self):
        return "%s:%s:%s" % (self.user, "Test", self.passw)

    def A2 (self, params):
        return "%s:%s" % (self.command, params["uri"])

    def check_response (self, params):
        if "qop" in params:
            data_str = params['nonce'] \
                        + ":" + params['nc'] \
                        + ":" + params['cnonce'] \
                        + ":" + params['qop'] \
                        + ":" + self.H (self.A2 (params))
        else:
            data_str = params['nonce'] + ":" + self.H (self.A2 (params))
        resp = self.KD (self.H (self.A1 ()), data_str)

        return True if resp == params['response'] else False

    def authorize_Digest (self, auth_header, auth_rule):
        if auth_header is None or auth_header.split(' ')[0] != 'Digest':
            return False
        else:
            self.user = auth_rule.auth_user
            self.passw = auth_rule.auth_pass
            params = self.parse_auth_header (auth_header)
            pass_auth = True
            if self.user != params['username'] or \
              self.nonce != params['nonce'] or self.opaque != params['opaque']:
                pass_auth = False
            req_attribs = ['username', 'realm', 'nonce', 'uri', 'response']
            for attrib in req_attribs:
                if not attrib in params:
                    pass_auth = False
            if not self.check_response (params):
                pass_auth = False
            return pass_auth

    def authorize_Both (self, auth_header, auth_rule):
        return False

    def authorize_Both_inline (self, auth_header, auth_rule):
        return False

    def Authentication (self, auth_rule):
        try:
            self.handle_auth (auth_rule)
        except ServerError as se:
            self.send_response (401, "Authorization Required")
            self.send_challenge (auth_rule.auth_type)
            self.finish_headers ()
            raise ServerError (se.__str__())

    def handle_auth (self, auth_rule):
        is_auth = True
        auth_header = self.headers.get ("Authorization")
        required_auth = auth_rule.auth_type
        if required_auth == "Both" or required_auth == "Both_inline":
            auth_type = auth_header.split(' ')[0] if auth_header else required_auth
        else:
            auth_type = required_auth
        try:
            assert hasattr (self, "authorize_" + auth_type)
            is_auth = getattr (self, "authorize_" + auth_type) (auth_header, auth_rule)
        except AssertionError:
            raise ServerError ("Authentication Mechanism " + auth_rule + " not supported")
        except AttributeError as ae:
            raise ServerError (ae.__str__())
        if is_auth is False:
            raise ServerError ("Unable to Authenticate")

    def is_authorized (self):
        is_auth = True
        auth_rule = self.get_rule_list ('Authentication')
        if auth_rule:
            auth_header = self.headers.get ("Authorization")
            req_auth = auth_rule.auth_type
            if req_auth == "Both" or req_auth == "Both_inline":
                auth_type = auth_header.split(' ')[0] if auth_header else req_auth
            else:
                auth_type = req_auth
            assert hasattr (self, "authorize_" + auth_type)
            is_auth = getattr (self, "authorize_" + auth_type) (auth_header, auth_rule)
            if is_auth is False:
                self.send_response (401)
                self.send_challenge (auth_type)
                self.finish_headers ()
        return is_auth

    def ExpectHeader (self, header_obj):
        exp_headers = header_obj.headers
        for header_line in exp_headers:
            header_recd = self.headers.get (header_line)
            if header_recd is None or header_recd != exp_headers[header_line]:
                self.send_error (400, "Expected Header " + header_line + " not found")
                self.finish_headers ()
                raise ServerError ("Header " + header_line + " not found")

    def expect_headers (self):
        """ This is modified code to handle a few changes. Should be removed ASAP """
        exp_headers_obj = self.get_rule_list ('ExpectHeader')
        if exp_headers_obj:
            exp_headers = exp_headers_obj.headers
            for header_line in exp_headers:
                header_re = self.headers.get (header_line)
                if header_re is None or header_re != exp_headers[header_line]:
                    self.send_error (400, 'Expected Header not Found')
                    self.end_headers ()
                    return False
        return True

    def RejectHeader (self, header_obj):
        rej_headers = header_obj.headers
        for header_line in rej_headers:
            header_recd = self.headers.get (header_line)
            if header_recd is not None and header_recd == rej_headers[header_line]:
                self.send_error (400, 'Blackisted Header ' + header_line + ' received')
                self.finish_headers ()
                raise ServerError ("Header " + header_line + ' received')

    def reject_headers (self):
        rej_headers = self.get_rule_list ("RejectHeader")
        if rej_headers:
            rej_headers = rej_headers.headers
            for header_line in rej_headers:
                header_re = self.headers.get (header_line)
                if header_re is not None and header_re == rej_headers[header_line]:
                    self.send_error (400, 'Blacklisted Header was Sent')
                    self.end_headers ()
                    return False
        return True

    def __log_request (self, method):
        req = method + " " + self.path
        self.server.request_headers.append (req)

    def send_head (self, method):
        """ Common code for GET and HEAD Commands.
        This method is overriden to use the fileSys dict.

        The method variable contains whether this was a HEAD or a GET Request.
        According to RFC 2616, the server should not differentiate between
        the two requests, however, we use it here for a specific test.
        """

        if self.path == "/":
            path = "index.html"
        else:
            path = self.path[1:]

        self.__log_request (method)

        if path in self.server.fileSys:
            self.rules = self.server.server_configs.get (path)

            for rule_name in self.rules:
                try:
                    assert hasattr (self, rule_name)
                    getattr (self, rule_name) (self.rules [rule_name])
                except AssertionError as ae:
                    msg = "Method " + rule_name + " not defined"
                    self.send_error (500, msg)
                    return (None, None)
                except ServerError as se:
                    print (se.__str__())
                    return (None, None)

            content = self.server.fileSys.get (path)
            content_length = len (content)
            try:
                self.range_begin = self.parse_range_header (
                    self.headers.get ("Range"), content_length)
            except InvalidRangeHeader as ae:
                # self.log_error("%s", ae.err_message)
                if ae.err_message == "Range Overflow":
                    self.send_response (416)
                    self.finish_headers ()
                    return (None, None)
                else:
                    self.range_begin = None
            if self.range_begin is None:
                self.send_response (200)
            else:
                self.send_response (206)
                self.send_header ("Accept-Ranges", "bytes")
                self.send_header ("Content-Range",
                                  "bytes %d-%d/%d" % (self.range_begin,
                                                      content_length - 1,
                                                      content_length))
                content_length -= self.range_begin
            cont_type = self.guess_type (path)
            self.send_header ("Content-type", cont_type)
            self.send_header ("Content-Length", content_length)
            self.finish_headers ()
            return (content, self.range_begin)
        else:
            self.send_error (404, "Not Found")
            return (None, None)

    def guess_type (self, path):
        base_name = basename ("/" + path)
        name, ext = splitext (base_name)
        extension_map = {
        ".txt"   :   "text/plain",
        ".css"   :   "text/css",
        ".html"  :   "text/html"
        }
        if ext in extension_map:
            return extension_map[ext]
        else:
            return "text/plain"


class HTTPd (threading.Thread):
    server_class = StoppableHTTPServer
    handler = _Handler
    def __init__ (self, addr=None):
        threading.Thread.__init__ (self)
        if addr is None:
            addr = ('localhost', 0)
        self.server_inst = self.server_class (addr, self.handler)
        self.server_address = self.server_inst.socket.getsockname()[:2]

    def run (self):
       self.server_inst.serve_forever ()

    def server_conf (self, file_list, server_rules):
        self.server_inst.server_conf (file_list, server_rules)


class HTTPSd (HTTPd):

   server_class = HTTPSServer

# vim: set ts=4 sts=4 sw=4 tw=80 et :