CS460-Projects/chatserver/server.py
2025-04-21 18:59:31 -07:00

230 lines
No EOL
14 KiB
Python

import os
import socket
import select
CHATPORT = 8181
BUFFER_SIZE = 1024
MAX_CONNECT_QUEUE = 10
def format_file_info(file_path):
"""Helper function to format file information."""
file_size = os.path.getsize(file_path)
if file_size < 1000:
size_str = f"{file_size} B"
elif file_size < 1000000:
size_str = f"{file_size / 1000:.2f} KB"
else:
size_str = f"{file_size / 1000000:.2f} MB"
file_type = "Directory" if os.path.isdir(file_path) else "File"
return f"{os.path.basename(file_path)} - {file_type} - {size_str}"
def main():
# set the flag variable to true for infinite loop
quitFlag = True
# create a socket object
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# set the socket options, SO_REUSEADDR allows to reuse the same port
# SO_KEEPALIVE enables the socket to send keepalive messages
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
# bind the socket to the address and port
server_socket.bind(('', CHATPORT))
# listen for incoming connections
server_socket.listen(MAX_CONNECT_QUEUE)
# set the server socket to non-blocking
server_socket.setblocking(False)
# create a list to store the sockets, server and client
socket_list = [server_socket]
# since a socket is associated with a username and a chatroom,
# and each one can only be associated one way at once, use dictionaries to
# associate with each other.
usernames = {}
chat_rooms = {}
# keep track of the states of each client connected, and if they are
# technically in an 'unsafe' state like in change username or chatroom mode.
client_states = {}
# Add a dictionary to store user-specific paths
user_paths = {}
# let the user know the server is listening on port CHATPORT.
print(f"Chatserver listening on port: {CHATPORT}")
# infinite loop for the program
while quitFlag:
# use the select function to monitor the sockets
read_sockets, _, _ = select.select(socket_list, [], [])
# loop through the sockets
for sock in read_sockets:
# if the socket is the server socket, accept the connection
if sock == server_socket:
client_socket, client_address = server_socket.accept()
client_socket.setblocking(False)
socket_list.append(client_socket)
print("\nAccepted connection from new client.")
client_socket.send(b"\nWelcome to the chat server!\n")
client_socket.send(b"\nUse '%!' to exit, or '%?' for help.\n")
client_socket.send(b"\nType in a username: ")
client_states[client_socket] = "WAITING_FOR_USERNAME"
user_paths[client_socket] = None # Initialize path for new client
# otherwise the socket is a client socket.
else:
# try to receive the message from the client
try:
message = sock.recv(BUFFER_SIZE).decode('utf-8')
if message:
state = client_states.get(sock, "NORMAL")
if state == "WAITING_FOR_USERNAME":
usernames[sock] = message.strip()
chat_rooms[sock] = "default"
sock.send(b"\nUsername accepted. You are now in the 'default' chatroom.")
client_states[sock] = "NORMAL"
user_paths[sock] = None # Initialize path for the user
elif state == "WAITING_FOR_NEW_USERNAME":
usernames[sock] = message.strip()
sock.send(b"\nUsername changed successfully.")
print(f"\nClient switched username to {usernames[sock]}.")
client_states[sock] = "NORMAL"
elif state == "WAITING_FOR_NEW_CHATROOM":
old_chatroom = chat_rooms[sock]
chat_rooms[sock] = message.strip()
sock.send(f"\nSwitched to chatroom '{chat_rooms[sock]}.'".encode('utf-8'))
print(f"\nClient switched to chatroom '{chat_rooms[sock]}.'")
if old_chatroom != "default" and old_chatroom not in chat_rooms.values():
print(f"\nChatroom '{old_chatroom}' is empty and removed.")
client_states[sock] = "NORMAL"
elif state == "NORMAL":
if message.startswith("@") and "-ls" in message:
# Parse the message format: @RECEIVING_USERNAME@SENDING_USERNAME -ls
parts = message.split()
if len(parts) >= 2 and "-ls" in parts[1]:
usernames_part = parts[0]
if usernames_part.count("@") == 2:
receiving_username, sending_username = usernames_part[1:].split("@")
# Find the receiving user's socket
receiving_sock = next(
(s for s, u in usernames.items() if u == receiving_username), None
)
sending_sock = next(
(s for s, u in usernames.items() if u == sending_username), None
)
if receiving_sock and sending_sock:
user_path = user_paths.get(receiving_sock)
if user_path and os.path.isdir(user_path):
# List files in the receiving user's directory
files = os.listdir(user_path)
if files:
file_list = "\n".join(
[format_file_info(os.path.join(user_path, f)) for f in files]
)
sending_sock.send(
f"Files in {receiving_username}'s directory:\n{file_list}".encode('utf-8')
)
else:
sending_sock.send(
f"No files in {receiving_username}'s directory.".encode('utf-8')
)
else:
sending_sock.send(
f"Error: {receiving_username} has no valid directory set.".encode('utf-8')
)
else:
sock.send(b"Error: One or both users not found.")
else:
sock.send(b"Error: Invalid message format.")
elif message.startswith("@") and "-f" in message:
# Parse the message format: @RECEIVING_USERNAME@SENDING_USERNAME -f FILENAME
parts = message.split()
if len(parts) >= 3 and "-f" in parts[1]:
usernames_part = parts[0]
if usernames_part.count("@") == 2:
receiving_username, sending_username = usernames_part[1:].split("@")
# Find the receiving user's socket
receiving_sock = next(
(s for s, u in usernames.items() if u == receiving_username), None
)
sending_sock = next(
(s for s, u in usernames.items() if u == sending_username), None
)
if receiving_sock and sending_sock:
if len(parts) == 3:
# File request: @RECEIVING_USERNAME@SENDING_USERNAME -f FILENAME
filename = parts[2]
receiving_sock.send(
f"FILE_REQUEST {sending_username} {filename}".encode('utf-8')
)
elif len(parts) > 5 and parts[-1] == "ENDFILE":
# File transfer: @RECEIVING_USERNAME@SENDING_USERNAME -f FILENAME FILETYPE FILELENGTH FILEBYTES ENDFILE
filename = parts[2]
filetype = parts[3]
filelength = int(parts[4])
filebytes = " ".join(parts[5:-1]).encode('utf-8')
receiving_sock.send(
f"FILE_TRANSFER {sending_username} {filename} {filetype} {filelength}".encode('utf-8')
)
receiving_sock.send(filebytes)
receiving_sock.send(b"ENDFILE")
else:
sock.send(b"Error: One or both users not found.")
else:
sock.send(b"Error: Invalid message format.")
elif message.strip() == "%!":
sock.close()
socket_list.remove(sock)
del usernames[sock]
del chat_rooms[sock]
del client_states[sock]
print("\nClient has closed connection.")
elif message.strip() == "%?":
print("\nClient requested help.")
sock.send(b"Help: (%?)\n")
sock.send(b"Send messages like normal. Use enter to send a message.\n")
sock.send(b"Available Commands:\n")
sock.send(b"\t%? : Show this help prompt.\n")
sock.send(b"\t%! : Exit from the Chat Server.\n")
sock.send(b"\t%* : Switch to another chatroom.\n")
sock.send(b"\t%$ : Change Username.\n")
elif message.strip() == "%*":
sock.send(b"\nEnter chatroom name: ")
client_states[sock] = "WAITING_FOR_NEW_CHATROOM"
elif message.strip() == "%$":
sock.send(b"\nEnter new username: ")
client_states[sock] = "WAITING_FOR_NEW_USERNAME"
else:
username = usernames[sock]
chat_room = chat_rooms[sock]
send_message = f"{username} >> {message}".encode('utf-8')
for client_sock in socket_list:
if client_sock != server_socket and chat_rooms.get(client_sock) == chat_room:
client_sock.send(send_message)
else:
sock.close()
socket_list.remove(sock)
if sock in usernames:
del usernames[sock]
if sock in chat_rooms:
old_chatroom = chat_rooms[sock]
del chat_rooms[sock]
if old_chatroom != "default" and old_chatroom not in chat_rooms.values():
print(f"\nChatroom '{old_chatroom}' is empty and has been removed.")
if sock in client_states:
del client_states[sock]
print("\nClient has closed connection.")
except Exception as err:
print(f"Error: {err}")
sock.close()
socket_list.remove(sock)
if sock in usernames:
del usernames[sock]
if sock in chat_rooms:
old_chatroom = chat_rooms[sock]
del chat_rooms[sock]
if old_chatroom != "default" and old_chatroom not in chat_rooms.values():
print(f"\nChatroom '{old_chatroom}' is empty and has been removed.")
if sock in client_states:
del client_states[sock]
print("\nClient has closed connection.")
server_socket.close()
if __name__ == "__main__":
main()