import chronos # an efficient library for async import stew/byteutils # various utils import libp2p ## # Create our custom protocol ## const TestCodec = "/test/proto/1.0.0" # custom protocol string identifier type TestProto = ref object of LPProtocol # declare a custom protocol proc new(T: typedesc[TestProto]): T = # every incoming connections will be in handled in this closure proc handle(conn: Connection, proto: string) {.async.} = echo "Got from remote - ", string.fromBytes(await conn.readLp(1024)) await conn.writeLp("Roger p2p!") # We must close the connections ourselves when we're done with it await conn.close() return T(codecs: @[TestCodec], handler: handle) ## # Helper to create a switch/node ## proc createSwitch(ma: MultiAddress, rng: ref HmacDrbgContext): Switch = var switch = SwitchBuilder .new() .withRng(rng) # Give the application RNG .withAddress(ma) # Our local address(es) .withTcpTransport() # Use TCP as transport .withMplex() # Use Mplex as muxer .withNoise() # Use Noise as secure manager .build() result = switch ## # The actual application ## proc main() {.async.} = let rng = newRng() # Single random number source for the whole application # port 0 will take a random available port # `tryGet` will throw an exception if the MultiAddress failed # (for instance, if the address is not well formatted) ma1 = MultiAddress.init("/ip4/0.0.0.0/tcp/0").tryGet() ma2 = MultiAddress.init("/ip4/0.0.0.0/tcp/0").tryGet() # setup the custom proto let testProto = TestProto.new() # setup the two nodes let switch1 = createSwitch(ma1, rng) #Create the two switches switch2 = createSwitch(ma2, rng) # mount the proto on switch1 # the node will now listen for this proto # and call the handler everytime a client request it switch1.mount(testProto) # Start the nodes. This will start the transports # and listen on each local addresses await switch1.start() await switch2.start() # the node addrs is populated with it's # actual port during the start # use the second node to dial the first node # using the first node peerid and address # and specify our custom protocol codec let conn = await switch2.dial(switch1.peerInfo.peerId, switch1.peerInfo.addrs, TestCodec) # conn is now a fully setup connection, we talk directly to the node1 custom protocol handler await conn.writeLp("Hello p2p!") # writeLp send a length prefixed buffer over the wire # readLp reads length prefixed bytes and returns a buffer without the prefix echo "Remote responded with - ", string.fromBytes(await conn.readLp(1024)) # We must close the connection ourselves when we're done with it await conn.close() await allFutures(switch1.stop(), switch2.stop()) # close connections and shutdown all transports waitFor(main())