return proto string from select, instead of bool

libp2p/multistream.nim

@@ -40,7 +40,8 @@ proc newMultistream*(): MultisteamSelect =
 
 proc select*(m: MultisteamSelect,
              conn: Connection,
-             proto: seq[string]): Future[bool] {.async.} =
+             proto: seq[string]): 
+             Future[string] {.async.} =
   ## select a remote protocol
   await conn.write(m.codec)   # write handshake
   if proto.len() > 0:
@@ -49,33 +50,38 @@ proc select*(m: MultisteamSelect,
   var ms = cast[string](await conn.readLp()) # read ms header
   ms.removeSuffix("\n")
   if ms != Codec:
-    return false
+    return ""
 
   if proto.len() == 0: # no protocols, must be a handshake call
-    return true
+    return ""
 
   ms = cast[string](await conn.readLp()) # read the first proto
   ms.removeSuffix("\n")
-  result = ms == proto[0]
+  if ms == proto[0]:
+    result = ms
 
-  if not result:
+  if not result.len > 0:
     for p in proto[1..<proto.len()]:
       await conn.writeLp(p) # select proto
       ms = cast[string](await conn.readLp()) # read the first proto
       ms.removeSuffix("\n")
-      result = ms == p
+      if ms == p:
-      if result: 
+        result = p
         break
 
 proc select*(m: MultisteamSelect,
              conn: Connection,
-             proto: string = ""): Future[bool] = 
+             proto: string): Future[string] = 
   result = if proto.len > 0: m.select(conn, @[proto]) else: m.select(conn, @[])
 
+proc select*(m: MultisteamSelect,
+             conn: Connection): Future[string] = 
+  result = 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)):
+  if not (await m.select(conn)).len > 0:
     return
 
   await conn.write(m.ls) # send ls
@@ -90,7 +96,7 @@ proc list*(m: MultisteamSelect,
 
 proc handle*(m: MultisteamSelect, conn: Connection) {.async, gcsafe.} =
   ## handle requests on connection
-  if not (await m.select(conn)):
+  if not (await m.select(conn)).len > 0:
     return
 
   while not conn.closed:

tests/testmultistream.nim

@@ -143,7 +143,7 @@ suite "Multistream select":
     proc testSelect(): Future[bool] {.async.} =
       let ms = newMultistream()
       let conn = newConnection(newTestSelectStream())
-      result = await ms.select(conn, @["/test/proto/1.0.0"])
+      result = (await ms.select(conn, @["/test/proto/1.0.0"])) == "/test/proto/1.0.0"
 
     check:
       waitFor(testSelect()) == true
@@ -255,8 +255,7 @@ suite "Multistream select":
       let transport2: TcpTransport = newTransport(TcpTransport)
       let conn = await transport2.dial(ma)
 
-      let res = await msDial.select(conn, @["/test/proto/1.0.0"])
+      check (await msDial.select(conn, @["/test/proto/1.0.0"])) == "/test/proto/1.0.0"
-      check res == true
 
       let hello = cast[string](await conn.readLp())
       result = hello == "Hello!"
@@ -328,8 +327,8 @@ suite "Multistream select":
       let transport2: TcpTransport = newTransport(TcpTransport)
       let conn = await transport2.dial(ma)
 
-      let res = await msDial.select(conn, @["/test/proto/1.0.0", "/test/no/proto/1.0.0"])
+      check (await msDial.select(conn, 
-      check res == true
+        @["/test/proto/1.0.0", "/test/no/proto/1.0.0"])) == "/test/proto/1.0.0"
 
       let hello = cast[string](await conn.readLp())
       result = hello == "Hello!"
@@ -367,11 +366,9 @@ suite "Multistream select":
       let transport2: TcpTransport = newTransport(TcpTransport)
       let conn = await transport2.dial(ma)
 
-      let res = await msDial.select(conn, @["/test/proto2/1.0.0", "/test/proto1/1.0.0"])
+      check (await msDial.select(conn, @["/test/proto2/1.0.0", "/test/proto1/1.0.0"])) == "/test/proto2/1.0.0"
-      check res == true
 
-      let hello = cast[string](await conn.readLp())
+      result = cast[string](await conn.readLp()) == "Hello from /test/proto2/1.0.0!"
-      result = hello == "Hello from /test/proto2/1.0.0!"
       await conn.close()
 
     check: