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A simple whoami server to analyze incoming HTTP requests
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"""A simple whoami server to analyze incoming HTTP requests | |
# For simplicity, we don't do: | |
# 1. Detect End of HTTP Request either by double CRLF(`\r\n\r\n`) or `Content-Length`. | |
# 2. Parse the HTTP request message. | |
# Instead, we just do: | |
# 1. Read max size of `GET` and `POST` requests data is 4096 bytes. | |
# 2. Close the connection for each request. | |
""" | |
import socket | |
import selectors | |
import argparse | |
sel = selectors.DefaultSelector() | |
def accept(server_sock: socket.socket, sel: selectors.BaseSelector, mask): | |
# conn: connection socket | |
conn, addr = server_sock.accept() # Should be ready | |
print(f"Accept - conn[{conn}] from addr[{addr}]\n") | |
conn.setblocking(False) | |
sel.register(conn, selectors.EVENT_READ, {"type": "connection_socket"}) | |
def read(conn: socket.socket, sel: selectors.BaseSelector, mask): | |
buffer = conn.recv(4096) | |
client_addr = conn.getpeername() | |
server_addr = conn.getsockname() | |
print(f"Read - data[{repr(buffer)}] in conn[{conn}] from addr[{client_addr}]\n") | |
if buffer: | |
data = buffer.decode("utf-8") | |
# Construct HTTP response message | |
message =( | |
"HTTP/1.1 200 OK\r\n", | |
"Content-type: text/html\r\n", | |
"Server:localhost\r\n\r\n", | |
f"""<!doctype html> | |
<html> | |
<body> | |
<h1>Welcome to the server!</h1> | |
<h2>Server address: {server_addr[0]}:{server_addr[1]}</h2> | |
<h3>You're connected through address: {client_addr[0]}:{client_addr[1]}</h3> | |
<body> | |
<pre>{data}<pre> | |
</body> | |
</body> | |
</html>""") | |
else: | |
message = ( | |
"HTTP/1.1 400 Bad Request\r\n", | |
"Content-type: text/html\r\n", | |
"Server:localhost\r\n\r\n", | |
) | |
message = "".join(message) | |
conn.sendall(message.encode("utf8")) | |
print(f'Close - conn[{conn}] from addr[{client_addr}]\n') | |
sel.unregister(conn) | |
conn.close() | |
def run(host="127.0.0.1", port=3234): | |
# server_sock: listening socket | |
server_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | |
server_sock.bind((host, port)) | |
server_sock.listen() | |
server_sock.setblocking(False) | |
sel.register(server_sock, selectors.EVENT_READ, {"type": "listening_socket"}) | |
while True: | |
print(f"Select register - file descriptors(fds):{list(sel.get_map())}\n") | |
# Set timeout for catching `CRTL+C` KeyboardInterrupt | |
events = sel.select(2.0) | |
for key, mask in events: | |
print(f"Select ready - fileobj[{key.fileobj}] fd[{key.fd}], events[{key.events}], data[{key.data}]\n") | |
if key.data["type"] == "listening_socket": | |
# Handle listening socket | |
accept(key.fileobj, sel, mask) | |
elif key.data["type"] == "connection_socket": | |
# Handle connection socket | |
read(key.fileobj, sel, mask) | |
else: | |
pass | |
HOST = "127.0.0.1" | |
PORT = 3234 | |
if __name__ == "__main__": | |
parser = argparse.ArgumentParser(prog='PROG') | |
parser.add_argument('-H', '--host', default=HOST) | |
parser.add_argument('-P', '--port', default=PORT, type=int) | |
args = parser.parse_args() | |
host = args.host | |
port = args.port | |
try: | |
run(host, port) | |
except KeyboardInterrupt: | |
# Code to run when Ctrl+C is pressed | |
print("\nCtrl+C detected. Exiting gracefully.") |
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