## Nim-LibP2P ## Copyright (c) 2018 Status Research & Development GmbH ## Licensed under either of ## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE)) ## * MIT license ([LICENSE-MIT](LICENSE-MIT)) ## at your option. ## This file may not be copied, modified, or distributed except according to ## those terms. import sequtils, strutils, strformat import chronos, chronicles import connection, varint, vbuffer, protocols/protocol logScope: topic = "Multistream" const MsgSize* = 64*1024 const Codec* = "/multistream/1.0.0" const MSCodec* = "\x13" & Codec & "\n" const Na = "\x03na\n" const Ls = "\x03ls\n" type MultisteamSelectException = object of CatchableError Matcher* = proc (proto: string): bool {.gcsafe.} HandlerHolder* = object proto*: string protocol*: LPProtocol match*: Matcher MultisteamSelect* = ref object of RootObj handlers*: seq[HandlerHolder] codec*: string na: string ls: string proc newMultistream*(): MultisteamSelect = new result result.codec = MSCodec result.ls = Ls result.na = Na proc select*(m: MultisteamSelect, conn: Connection, proto: seq[string]): Future[string] {.async.} = trace "initiating handshake", codec = m.codec ## select a remote protocol await conn.write(m.codec) # write handshake if proto.len() > 0: trace "selecting proto", proto = proto await conn.writeLp((proto[0] & "\n")) # select proto result = cast[string](await conn.readLp()) # read ms header result.removeSuffix("\n") if result != Codec: trace "handshake failed", codec = result return "" if proto.len() == 0: # no protocols, must be a handshake call return result = cast[string](await conn.readLp()) # read the first proto trace "reading first requested proto" result.removeSuffix("\n") if result == proto[0]: trace "succesfully selected ", proto = proto return if not result.len > 0: trace "selecting one of several protos" for p in proto[1.. 0: result = (await m.select(conn, @[proto])) == proto else: result = (await m.select(conn, @[])) == Codec proc select*(m: MultisteamSelect, conn: Connection): Future[bool] = m.select(conn, "") proc list*(m: MultisteamSelect, conn: Connection): Future[seq[string]] {.async.} = ## list remote protos requests on connection if not await m.select(conn): return await conn.write(m.ls) # send ls var list = newSeq[string]() let ms = cast[string](await conn.readLp()) for s in ms.split("\n"): if s.len() > 0: list.add(s) result = list proc handle*(m: MultisteamSelect, conn: Connection) {.async, gcsafe.} = trace "handle: starting multistream handling" while not conn.closed: var ms = cast[string](await conn.readLp()) ms.removeSuffix("\n") trace "handle: got request for ", ms if ms.len() <= 0: trace "handle: invalid proto" await conn.write(m.na) if m.handlers.len() == 0: trace "handle: sending `na` for protocol ", protocol = ms await conn.write(m.na) continue case ms: of "ls": trace "handle: listing protos" var protos = "" for h in m.handlers: protos &= (h.proto & "\n") await conn.writeLp(protos) of Codec: await conn.write(m.codec) else: for h in m.handlers: if (not isNil(h.match) and h.match(ms)) or ms == h.proto: trace "found handler for", protocol = ms await conn.writeLp((h.proto & "\n")) try: await h.protocol.handler(conn, ms) return except Exception as exc: warn "exception while handling ", msg = exc.msg warn "no handlers for ", protocol = ms await conn.write(m.na) proc addHandler*[T: LPProtocol](m: MultisteamSelect, codec: string, protocol: T, matcher: Matcher = nil) = ## register a protocol # TODO: This is a bug in chronicles, # it break if I uncoment this line. # Which is almost the same as the # one on the next override of addHandler # # trace "registering protocol", codec = codec m.handlers.add(HandlerHolder(proto: codec, protocol: protocol, match: matcher)) proc addHandler*[T: LPProtoHandler](m: MultisteamSelect, codec: string, handler: T, matcher: Matcher = nil) = ## helper to allow registering pure handlers trace "registering proto handler", codec = codec let protocol = new LPProtocol protocol.codec = codec protocol.handler = handler m.handlers.add(HandlerHolder(proto: codec, protocol: protocol, match: matcher))