196 lines
6.0 KiB
Python
Executable File
196 lines
6.0 KiB
Python
Executable File
#!/usr/bin/env python
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"""A simple chat server using Veilid's DHT."""
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import argparse
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import asyncio
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import sys
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import config
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import veilid
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QUIT = b"QUIT"
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async def noop_callback(*args, **kwargs):
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"""In the real world, we'd use this to process interesting incoming events."""
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return
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async def chatter(rc: veilid.api.RoutingContext, key: str, send_channel: int, recv_channel: int):
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"""Read input, write it to the DHT, and print the response from the DHT."""
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last_seq = -1
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send_subkey = veilid.types.ValueSubkey(send_channel)
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recv_subkey = veilid.types.ValueSubkey(recv_channel)
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# Prime the pumps. Especially when starting the conversation, this
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# causes the DHT key to propagate to the network.
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await rc.set_dht_value(key, send_subkey, b"Hello from the world!")
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while True:
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try:
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msg = input("SEND> ")
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except EOFError:
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# Cat got your tongue? Hang up.
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print("Closing the chat.")
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await rc.set_dht_value(key, send_subkey, QUIT)
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return
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# Write the input message to the DHT key.
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await rc.set_dht_value(key, send_subkey, msg.encode())
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# In the real world, don't do this. People may tease you for it.
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# This is meant to be easy to understand for demonstration
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# purposes, not a great pattern. Instead, you'd want to use the
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# callback function to handle events asynchronously.
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while True:
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# Try to get an updated version of the receiving subkey.
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resp = await rc.get_dht_value(key, recv_subkey, True)
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if resp is None:
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continue
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# If the other party hasn't sent a newer message, try again.
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if resp.seq == last_seq:
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continue
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if resp.data == QUIT:
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print("Other end closed the chat.")
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return
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print(f"RECV< {resp.data.decode()}")
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last_seq = resp.seq
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break
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async def start(host: str, port: int, name: str):
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"""Begin a conversation with a friend."""
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conn = await veilid.json_api_connect(host, port, noop_callback)
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keys = config.read_keys()
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my_key = veilid.KeyPair(keys["self"])
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members = [
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veilid.types.DHTSchemaSMPLMember(my_key.key(), 1),
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veilid.types.DHTSchemaSMPLMember(keys["peers"][name], 1),
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]
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router = await conn.new_routing_context()
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async with router:
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rec = await router.create_dht_record(veilid.DHTSchema.smpl(0, members))
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print(f"New chat key: {rec.key}")
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print("Give that to your friend!")
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# Close this key first. We'll reopen it for writing with our saved key.
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await router.close_dht_record(rec.key)
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await router.open_dht_record(rec.key, veilid.KeyPair(keys["self"]))
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try:
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# Write to the 1st subkey and read from the 2nd.
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await chatter(router, rec.key, 0, 1)
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finally:
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await router.close_dht_record(rec.key)
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await router.delete_dht_record(rec.key)
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async def respond(host: str, port: int, key: str):
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"""Reply to a friend's chat."""
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conn = await veilid.json_api_connect(host, port, noop_callback)
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keys = config.read_keys()
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my_key = veilid.KeyPair(keys["self"])
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router = await conn.new_routing_context()
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async with router:
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await router.open_dht_record(key, my_key)
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# As the responder, we're writing to the 2nd subkey and reading from the 1st.
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await chatter(router, key, 1, 0)
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async def keygen(host: str, port: int):
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"""Generate a keypair."""
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conn = await veilid.json_api_connect(host, port, noop_callback)
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crypto_system = await conn.get_crypto_system(veilid.CryptoKind.CRYPTO_KIND_VLD0)
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async with crypto_system:
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my_key = await crypto_system.generate_key_pair()
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keys = config.read_keys()
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if keys["self"]:
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print("You already have a keypair.")
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sys.exit(1)
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keys["self"] = my_key
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config.write_keys(keys)
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print(f"Your new public key is {my_key.key()}. Share it with your friends!")
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async def add_friend(host: str, port: int, name: str, pubkey: str):
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"""Add a friend's public key."""
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keys = config.read_keys()
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keys["peers"][name] = pubkey
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config.write_keys(keys)
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async def clean(host: str, port: int, key: str):
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"""Delete a DHT key."""
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conn = await veilid.json_api_connect(host, port, noop_callback)
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router = await conn.new_routing_context()
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async with router:
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await router.close_dht_record(key)
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await router.delete_dht_record(key)
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def handle_command_line(arglist: list[str]):
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"""Process the command line.
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This isn't the interesting part."""
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parser = argparse.ArgumentParser(description="Veilid chat demonstration")
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parser.add_argument("--host", default="localhost", help="Address of the Veilid server host.")
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parser.add_argument("--port", type=int, default=5959, help="Port of the Veilid server.")
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subparsers = parser.add_subparsers(required=True)
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cmd_start = subparsers.add_parser("start", help=start.__doc__)
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cmd_start.add_argument("name", help="Your friend's name")
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cmd_start.set_defaults(func=start)
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cmd_respond = subparsers.add_parser("respond", help=respond.__doc__)
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cmd_respond.add_argument("key", help="The chat's DHT key")
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cmd_respond.set_defaults(func=respond)
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cmd_keygen = subparsers.add_parser("keygen", help=keygen.__doc__)
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cmd_keygen.set_defaults(func=keygen)
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cmd_add_friend = subparsers.add_parser("add-friend", help=add_friend.__doc__)
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cmd_add_friend.add_argument("name", help="Your friend's name")
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cmd_add_friend.add_argument("pubkey", help="Your friend's public key")
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cmd_add_friend.set_defaults(func=add_friend)
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cmd_clean = subparsers.add_parser("clean", help=clean.__doc__)
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cmd_clean.add_argument("key", help="DHT key to delete")
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cmd_clean.set_defaults(func=clean)
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args = parser.parse_args(arglist)
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kwargs = args.__dict__
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func = kwargs.pop("func")
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asyncio.run(func(**kwargs))
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if __name__ == "__main__":
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handle_command_line(sys.argv[1:])
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