httpserver.py

import socket
import threading
from httphandler import HTTPHandler
from posthandler.redirector import POSTHandlerRedirector
from exceptions import UploadedFileTooLarge, MultipartPOSTMissingContentLength
from httpresponse import HTTPResponse


class HTTPServer:
    def __init__(self, http_handler=HTTPHandler, max_exchange_mb=500):
        self.socket = socket.create_server(('0.0.0.0', 80))
        self.httphandler = http_handler
        self.max_exchange_bytes = max_exchange_mb * 1_000_000

    def start(self):
        self.socket.listen()
        print('HTTP server up!')
        while True:
            user_socket, address = self.socket.accept()
            threading.Thread(target=self.handle_user, args=(user_socket,)).start()

    def handle_user(self, user_socket: socket.socket):
        try:
            exchange = self.receive_exchange(user_socket)
        except UploadedFileTooLarge:
            response = HTTPResponse(413).bytes()
        except MultipartPOSTMissingContentLength:
            response = HTTPResponse(411).bytes()
        except ConnectionAbortedError:
            user_socket.close()
            return False
        else:
            response = self.httphandler(exchange, posthandler=POSTHandlerRedirector).handle()

        user_socket.send(response)
        user_socket.close()
        return True

    def receive_exchange(self, user_socket: socket.socket):
        exchange = user_socket.recv(1024)
        if len(exchange) == 0:
            raise ConnectionAbortedError

        http = self.httphandler.http_to_dict(exchange)
        if http['method'] == 'POST' and http['Content-Type'].startswith('multipart/form-data'):
            if 'Content-Length' not in http.keys():
                raise MultipartPOSTMissingContentLength
            elif int(http['Content-Length']) > self.max_exchange_bytes:
                raise UploadedFileTooLarge

            additional_data = b''
            received_length = len(http['data'])
            while received_length < int(http['Content-Length']):
                additional_data += user_socket.recv(4096)
                received_length = len(additional_data) + len(http['data'])
            exchange += additional_data

        return exchange


if __name__ == '__main__':
    HTTPServer().start()