nim-libp2p/examples/directchat.nim

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when not(compileOption("threads")):
{.fatal: "Please, compile this program with the --threads:on option!".}
import tables, strformat, strutils
import chronos # an efficient library for async
import ../libp2p/[switch, # manage transports, a single entry point for dialing and listening
multistream, # tag stream with short header to identify it
crypto/crypto, # cryptographic functions
errors, # error handling utilities
protocols/identify, # identify the peer info of a peer
connection, # create and close stream read / write connections
transports/transport, # listen and dial to other peers using p2p protocol
transports/tcptransport, # listen and dial to other peers using client-server protocol
multiaddress, # encode different addressing schemes. For example, /ip4/7.7.7.7/tcp/6543 means it is using IPv4 protocol and TCP
peerinfo, # manage the information of a peer, such as peer ID and public / private key
peer, # Implement how peers interact
protocols/protocol, # define the protocol base type
protocols/secure/secure, # define the protocol of secure connection
protocols/secure/secio, # define the protocol of secure input / output, allows encrypted communication that uses public keys to validate signed messages instead of a certificate authority like in TLS
muxers/muxer, # define an interface for stream multiplexing, allowing peers to offer many protocols over a single connection
muxers/mplex/mplex, # implement stream multiplexing
muxers/mplex/types] # define some contants and message types for stream multiplexing
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const ChatCodec = "/nim-libp2p/chat/1.0.0"
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const DefaultAddr = "/ip4/127.0.0.1/tcp/55505"
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const Help = """
Commands: /[?|hep|connect|disconnect|exit]
help: Prints this help
connect: dials a remote peer
disconnect: ends current session
exit: closes the chat
"""
type ChatProto = ref object of LPProtocol
switch: Switch # a single entry point for dialing and listening to peer
transp: StreamTransport # transport streams between read & write file descriptor
conn: Connection # create and close read & write stream
connected: bool # if the node is connected to another peer
started: bool # if the node has started
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proc initAddress(T: type MultiAddress, str: string): T =
let address = MultiAddress.init(str)
if IPFS.match(address) and matchPartial(multiaddress.TCP, address):
result = address
else:
raise newException(MultiAddressError,
"Invalid bootstrap node multi-address")
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proc dialPeer(p: ChatProto, address: string) {.async.} =
let multiAddr = MultiAddress.initAddress(address);
let parts = address.split("/")
let remotePeer = PeerInfo.init(parts[^1],
[multiAddr])
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echo &"dialing peer: {multiAddr}"
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p.conn = await p.switch.dial(remotePeer, ChatCodec)
p.connected = true
proc readAndPrint(p: ChatProto) {.async.} =
while true:
while p.connected:
# TODO: echo &"{p.id} -> "
echo cast[string](await p.conn.readLp())
await sleepAsync(100.millis)
proc writeAndPrint(p: ChatProto) {.async.} =
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while true:
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if not p.connected:
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echo "type an address or wait for a connection:"
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echo "type /[help|?] for help"
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let line = await p.transp.readLine()
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if line.startsWith("/help") or line.startsWith("/?") or not p.started:
echo Help
continue
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if line.startsWith("/disconnect"):
echo "Ending current session"
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if p.connected and p.conn.closed.not:
await p.conn.close()
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p.connected = false
elif line.startsWith("/connect"):
if p.connected:
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var yesno = "N"
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echo "a session is already in progress, do you want end it [y/N]?"
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yesno = await p.transp.readLine()
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if yesno.cmpIgnoreCase("y") == 0:
await p.conn.close()
p.connected = false
elif yesno.cmpIgnoreCase("n") == 0:
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continue
else:
echo "unrecognized response"
continue
echo "enter address of remote peer"
let address = await p.transp.readLine()
if address.len > 0:
await p.dialPeer(address)
elif line.startsWith("/exit"):
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if p.connected and p.conn.closed.not:
await p.conn.close()
p.connected = false
await p.switch.stop()
echo "quitting..."
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quit(0)
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else:
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if p.connected:
await p.conn.writeLp(line)
else:
try:
if line.startsWith("/") and "ipfs" in line:
await p.dialPeer(line)
except:
echo &"unable to dial remote peer {line}"
echo getCurrentExceptionMsg()
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proc readWriteLoop(p: ChatProto) {.async.} =
asyncCheck p.writeAndPrint() # execute the async function but does not block
asyncCheck p.readAndPrint()
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proc newChatProto(switch: Switch, transp: StreamTransport): ChatProto =
var chatproto = ChatProto(switch: switch, transp: transp, codec: ChatCodec)
# create handler for incoming connection
proc handle(stream: Connection, proto: string) {.async.} =
if chatproto.connected and not chatproto.conn.closed:
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echo "a chat session is already in progress - disconnecting!"
await stream.close()
else:
chatproto.conn = stream
chatproto.connected = true
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# assign the new handler
chatproto.handler = handle
return chatproto
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proc readInput(wfd: AsyncFD) {.thread.} =
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## This procedure performs reading from `stdin` and sends data over
## pipe to main thread.
let transp = fromPipe(wfd)
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while true:
let line = stdin.readLine()
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discard waitFor transp.write(line & "\r\n")
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proc processInput(rfd: AsyncFD) {.async.} =
let transp = fromPipe(rfd)
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let seckey = PrivateKey.random(RSA)
let peerInfo = PeerInfo.init(seckey)
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var localAddress = DefaultAddr
while true:
echo &"Type an address to bind to or Enter to use the default {DefaultAddr}"
let a = await transp.readLine()
try:
if a.len > 0:
peerInfo.addrs.add(Multiaddress.init(a))
break
peerInfo.addrs.add(Multiaddress.init(localAddress))
break
except:
echo "invalid address"
localAddress = DefaultAddr
continue
# a constructor for building different multiplexers under various connections
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proc createMplex(conn: Connection): Muxer =
result = newMplex(conn)
let mplexProvider = newMuxerProvider(createMplex, MplexCodec)
let transports = @[Transport(newTransport(TcpTransport))]
let muxers = [(MplexCodec, mplexProvider)].toTable()
let identify = newIdentify(peerInfo)
let secureManagers = [(SecioCodec, Secure(newSecio(seckey)))].toTable()
let switch = newSwitch(peerInfo,
transports,
identify,
muxers,
secureManagers)
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let chatProto = newChatProto(switch, transp)
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switch.mount(chatProto)
let libp2pFuts = await switch.start()
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chatProto.started = true
let id = peerInfo.peerId.pretty
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echo "PeerID: " & id
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echo "listening on: "
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for a in peerInfo.addrs:
echo &"{a}/ipfs/{id}"
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await chatProto.readWriteLoop()
await allFuturesThrowing(libp2pFuts)
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proc main() {.async.} =
let (rfd, wfd) = createAsyncPipe()
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if rfd == asyncInvalidPipe or wfd == asyncInvalidPipe:
raise newException(ValueError, "Could not initialize pipe!")
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var thread: Thread[AsyncFD]
thread.createThread(readInput, wfd)
await processInput(rfd)
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when isMainModule: # isMainModule = true when the module is compiled as the main file
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waitFor(main())