nim-libp2p/libp2p/multistreamselect.nim

110 lines
2.9 KiB
Nim

## 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
import chronos
import connection, varint, vbuffer
const MsgSize* = 64*1024
const Codec* = "/multistream/1.0.0"
const MultiCodec* = "\x19" & Codec & "\n"
const Na = "\x3na\n"
const Ls = "\x3ls\n"
type
MultisteamSelectException = object of CatchableError
Handler* = proc (conn: Connection, proto: string): Future[void]
Matcher* = proc (proto: string): bool
HandlerHolder* = object
proto: string
handler: Handler
match: Matcher
MultisteamSelect* = ref object of RootObj
handlers*: seq[HandlerHolder]
codec*: string
na*: string
ls*: string
proc newMultistream*(): MultisteamSelect =
new result
result.codec = MultiCodec
result.ls = Ls
result.na = Na
proc select*(m: MultisteamSelect, conn: Connection, proto: string = ""): Future[bool] {.async.} =
## select a remote protocol
## TODO: select should support a list of protos to be selected
await conn.write(m.codec) # write handshake
if proto.len() > 0:
await conn.writeLp(proto) # select proto
var ms = cast[string](await conn.readLp())
ms.removeSuffix("\n")
if ms != Codec:
return false
if proto.len() <= 0:
return true
ms = cast[string](await conn.readLp())
ms.removeSuffix("\n")
result = ms == proto
proc list*(m: MultisteamSelect, conn: Connection): Future[seq[string]] {.async.} =
## list remote protos requests on connection
if not (await m.select(conn)):
return
var list = newSeq[string]()
let ms = cast[string](await conn.readLp())
for s in ms.split("\n"):
list.add(s)
result = list
proc handle*(m: MultisteamSelect, conn: Connection) {.async.} =
## handle requests on connection
if not (await m.select(conn)):
return
while not conn.closed:
var ms = cast[string](await conn.readLp())
ms.removeSuffix("\n")
if ms.len() <= 0:
await conn.write(m.na)
if m.handlers.len() == 0:
await conn.write(m.na)
continue
case ms:
of "ls":
for h in m.handlers:
await conn.writeLp(h.proto & "\n")
else:
for h in m.handlers:
if (not isNil(h.match) and h.match(ms)) or ms == h.proto:
await h.handler(conn, ms)
return
else:
await conn.write(m.na)
proc addHandler*(m: MultisteamSelect,
proto: string,
handler: Handler,
matcher: Matcher = nil) =
## register a handler for the protocol
m.handlers.add(HandlerHolder(proto: proto,
handler: handler,
match: matcher))