nim-libp2p/docs/tutorial/second.nim

206 lines
7.5 KiB
Nim

when not(compileOption("threads")):
{.fatal: "Please, compile this program with the --threads:on option!".}
import tables, strformat, strutils, bearssl
import chronos # an efficient library for async
import ../libp2p/[switch, # manage transports, a single entry point for dialing and listening
builders, # helper to build the switch object
multistream, # tag stream with short header to identify it
multicodec, # multicodec utilities
crypto/crypto, # cryptographic functions
errors, # error handling utilities
protocols/identify, # identify the peer info of a peer
stream/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
peerid, # 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] # define some contants and message types for stream multiplexing
const ChatCodec = "/nim-libp2p/chat/1.0.0"
const DefaultAddr = "/ip4/127.0.0.1/tcp/55505"
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
proc readAndPrint(p: ChatProto) {.async.} =
while true:
var strData = await p.conn.readLp(1024)
strData &= '\0'.uint8
var str = cast[cstring](addr strdata[0])
echo $p.switch.peerInfo.peerId & ": " & $str
await sleepAsync(100.millis)
proc dialPeer(p: ChatProto, address: string) {.async.} =
let
multiAddr = MultiAddress.init(address).tryGet()
# split the peerId part /p2p/...
peerIdBytes = multiAddr[multiCodec("p2p")]
.tryGet()
.protoAddress()
.tryGet()
remotePeer = PeerID.init(peerIdBytes).tryGet()
# split the wire address
ip4Addr = multiAddr[multiCodec("ip4")].tryGet()
tcpAddr = multiAddr[multiCodec("tcp")].tryGet()
wireAddr = ip4Addr & tcpAddr
echo &"dialing peer: {multiAddr}"
p.conn = await p.switch.dial(remotePeer, @[wireAddr], ChatCodec)
p.connected = true
asyncSpawn p.readAndPrint()
proc writeAndPrint(p: ChatProto) {.async.} =
while true:
if not p.connected:
echo "type an address or wait for a connection:"
echo "type /[help|?] for help"
let line = await p.transp.readLine()
if line.startsWith("/help") or line.startsWith("/?") or not p.started:
echo Help
continue
if line.startsWith("/disconnect"):
echo "Ending current session"
if p.connected and p.conn.closed.not:
await p.conn.close()
p.connected = false
elif line.startsWith("/connect"):
if p.connected:
var yesno = "N"
echo "a session is already in progress, do you want end it [y/N]?"
yesno = await p.transp.readLine()
if yesno.cmpIgnoreCase("y") == 0:
await p.conn.close()
p.connected = false
elif yesno.cmpIgnoreCase("n") == 0:
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"):
if p.connected and p.conn.closed.not:
await p.conn.close()
p.connected = false
await p.switch.stop()
echo "quitting..."
quit(0)
else:
if p.connected:
await p.conn.writeLp(line)
else:
try:
if line.startsWith("/") and "p2p" in line:
await p.dialPeer(line)
except:
echo &"unable to dial remote peer {line}"
echo getCurrentExceptionMsg()
proc readWriteLoop(p: ChatProto) {.async.} =
await p.writeAndPrint()
proc newChatProto(switch: Switch, transp: StreamTransport): ChatProto =
var chatproto = ChatProto(switch: switch, transp: transp, codecs: @[ChatCodec])
# create handler for incoming connection
proc handle(stream: Connection, proto: string) {.async.} =
if chatproto.connected and not chatproto.conn.closed:
echo "a chat session is already in progress - disconnecting!"
await stream.close()
else:
chatproto.conn = stream
chatproto.connected = true
await chatproto.readAndPrint()
# assign the new handler
chatproto.handler = handle
return chatproto
proc readInput(wfd: AsyncFD) {.thread.} =
## This procedure performs reading from `stdin` and sends data over
## pipe to main thread.
let transp = fromPipe(wfd)
while true:
let line = stdin.readLine()
discard waitFor transp.write(line & "\r\n")
proc processInput(rfd: AsyncFD, rng: ref BrHmacDrbgContext) {.async.} =
let transp = fromPipe(rfd)
let seckey = PrivateKey.random(RSA, rng[]).get()
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:
localAddress = a
break
# uise default
break
except:
echo "invalid address"
localAddress = DefaultAddr
continue
var switch = SwitchBuilder
.init()
.withRng(rng)
.withPrivateKey(seckey)
.withAddress(MultiAddress.init(localAddress).tryGet())
.build()
let chatProto = newChatProto(switch, transp)
switch.mount(chatProto)
let libp2pFuts = await switch.start()
chatProto.started = true
let id = $switch.peerInfo.peerId
echo "PeerID: " & id
echo "listening on: "
for a in switch.peerInfo.addrs:
echo &"{a}/p2p/{id}"
await chatProto.readWriteLoop()
await allFuturesThrowing(libp2pFuts)
proc main() {.async.} =
let rng = newRng() # Singe random number source for the whole application
let (rfd, wfd) = createAsyncPipe()
if rfd == asyncInvalidPipe or wfd == asyncInvalidPipe:
raise newException(ValueError, "Could not initialize pipe!")
var thread: Thread[AsyncFD]
thread.createThread(readInput, wfd)
await processInput(rfd, rng)
when isMainModule: # isMainModule = true when the module is compiled as the main file
waitFor(main())