Improve documentation, cleanup duplicated code

server/command.py

@@ -3,8 +3,6 @@ import os
 import sys
 from abc import ABC, abstractmethod
 from datetime import datetime
-from time import mktime
-from wsgiref.handlers import format_date_time
 
 from httplib import parser
 from httplib.exceptions import NotFound, Forbidden, NotModified
@@ -62,14 +60,6 @@ class AbstractCommand(ABC):
     def _conditional_headers(self):
         pass
 
-    def _get_date(self):
-        """
-        Returns a string representation of the current date according to RFC 1123.
-        """
-        now = datetime.now()
-        stamp = mktime(now.timetuple())
-        return format_date_time(stamp)
-
     @abstractmethod
     def execute(self):
         pass
@@ -81,7 +71,7 @@ class AbstractCommand(ABC):
         self._process_conditional_headers()
 
         message = f"HTTP/1.1 {status} {status_message[status]}\r\n"
-        message += f"Date: {self._get_date()}\r\n"
+        message += f"Date: {parser.get_date()}\r\n"
 
         content_length = len(body)
         message += f"Content-Length: {content_length}\r\n"

server/requesthandler.py

@@ -1,12 +1,9 @@
 import logging
 import os
 import sys
-from datetime import datetime
 from socket import socket
-from time import mktime
 from typing import Union
 from urllib.parse import ParseResultBytes, ParseResult
-from wsgiref.handlers import format_date_time
 
 from httplib import parser
 from httplib.exceptions import MethodNotAllowed, BadRequest, UnsupportedEncoding, NotImplemented, NotFound, \
@@ -21,8 +18,11 @@ METHODS = ("GET", "HEAD", "PUT", "POST")
 
 
 class RequestHandler:
+    """
+    Processes incoming HTTP request messages.
+    """
+
     conn: HTTPSocket
-    root = os.path.join(os.path.dirname(sys.argv[0]), "public")
 
     def __init__(self, conn: socket, host):
         self.conn = ServerSocket(conn, host)
@@ -42,15 +42,20 @@ class RequestHandler:
 
     def _handle_message(self, retriever, line):
         lines = retriever.retrieve()
+
+        # Parse the request-line and headers
         (method, target, version) = parser.parse_request_line(line)
         headers = parser.parse_headers(lines)
 
+        # Create the response message object
         message = Message(version, method, target, headers, retriever.buffer)
 
         logging.debug("---request begin---\r\n%s---request end---", "".join(message.raw))
 
+        # validate if the request is valid
         self._validate_request(message)
 
+        # The body (if available) hasn't been retrieved up till now.
         body = b""
         if self._has_body(headers):
             try:
@@ -64,14 +69,25 @@ class RequestHandler:
 
         message.body = body
 
-        # completed message
-
+        # message completed
         cmd = command.create(message)
         msg = cmd.execute()
+
         logging.debug("---response begin---\r\n%s\r\n---response end---", msg.split(b"\r\n\r\n", 1)[0].decode(FORMAT))
+        # Send the response message
         self.conn.conn.sendall(msg)
 
     def _check_request_line(self, method: str, target: Union[ParseResultBytes, ParseResult], version):
+        """
+        Checks if the request-line is valid. Throws an appriopriate exception if not.
+        @param method: HTTP request method
+        @param target: The request target
+        @param version: The HTTP version
+        @raise MethodNotAllowed: if the method is not any of the allowed methods in `METHODS`
+        @raise HTTPVersionNotSupported: If the HTTP version is not supported by this server
+        @raise BadRequest: If the scheme of the target is not supported
+        @raise NotFound: If the target is not found on this server
+        """
 
         if method not in METHODS:
             raise MethodNotAllowed(METHODS)
@@ -91,12 +107,25 @@ class RequestHandler:
             raise NotFound(str(target))
 
     def _validate_request(self, msg):
+        """
+        Validates the message request-line and headers. Throws an error if the message is invalid.
+
+        @see: _check_request_line for exceptions raised when validating the request-line.
+        @param msg: the message to validate
+        @raise BadRequest: if HTTP 1.1 and the Host header is missing
+        """
+
         if msg.version == "1.1" and "host" not in msg.headers:
             raise BadRequest("Missing host header")
 
         self._check_request_line(msg.method, msg.target, msg.version)
 
     def _has_body(self, headers):
+        """
+        Check if the headers notify the existing of a message body.
+        @param headers: the headers to check
+        @return: True if the message has a body. False otherwise.
+        """
 
         if "transfer-encoding" in headers:
             return True
@@ -106,16 +135,10 @@ class RequestHandler:
 
         return False
 
-    @staticmethod
-    def _get_date():
-        now = datetime.now()
-        stamp = mktime(now.timetuple())
-        return format_date_time(stamp)
-
     @staticmethod
     def send_error(client: socket, code, message):
         message = f"HTTP/1.1 {code} {message}\r\n"
-        message += RequestHandler._get_date() + "\r\n"
+        message += parser.get_date() + "\r\n"
         message += "Content-Length: 0\r\n"
         message += "\r\n"