add compression support for websocket rpc server-client

fixes #62

json_rpc/clients/websocketclient.nim

@@ -1,6 +1,7 @@
 import
   std/[strtabs, tables, uri, strutils],
   pkg/[chronos, ws/ws, chronicles],
+  ws/extensions/compression/deflate,
   ../client
 
 export client
@@ -67,26 +68,28 @@ proc processData(client: RpcWebSocketClient) {.async.} =
     client.onDisconnect()
 
 proc connect*(client: RpcWebSocketClient, uri: string,
+              compression: bool = false,
               flags: set[TLSFlags] = {
                 NoVerifyHost, NoVerifyServerName}) {.async.} =
-  try:
 
-    let uri = parseUri(uri)
-    let secure = uri.scheme == "wss"
-    let port = parseInt(uri.port)
+  var ext: seq[ExtFactory] = if compression:
+                               @[deflateFactory()]
+                             else:
+                               @[]
+  let uri = parseUri(uri)
+  let secure = uri.scheme == "wss"
+  let port = parseInt(uri.port)
 
-    let ws = await WebSocket.connect(
-      host = uri.hostname,
-      port = Port(port),
-      path = uri.path,
-      secure=secure,
-      flags=flags
-    )
-    client.transport = ws
-    client.uri = uri
-
-  except WebSocketError as exc:
-    error "WebSocket error", exception = exc.msg
+  let ws = await WebSocket.connect(
+    host = uri.hostname,
+    port = Port(port),
+    path = uri.path,
+    secure=secure,
+    flags=flags,
+    factories=ext
+  )
+  client.transport = ws
+  client.uri = uri
 
   client.loop = processData(client)
 

json_rpc/servers/websocketserver.nim

@@ -1,5 +1,6 @@
 import
   chronicles, httputils, chronos, ws/ws,
+  ws/extensions/compression/deflate,
   ".."/[errors, server]
 
 export server
@@ -56,8 +57,17 @@ proc handleRequest(rpc: RpcWebSocketServer, request: HttpRequest) {.async.} =
   except WebSocketError as exc:
     error "WebSocket error:", exception = exc.msg
 
+proc initWebsocket(rpc: RpcWebSocketServer, compression: bool) =
+  let deflateFactory = deflateFactory()
+
+  if compression:
+    rpc.wsserver = WSServer.new(factories = [deflateFactory])
+  else:
+    rpc.wsserver = WSServer.new()
+
 proc newRpcWebSocketServer*(
   address: TransportAddress,
+  compression: bool = false,
   flags: set[ServerFlags] = {ServerFlags.TcpNoDelay,
     ServerFlags.ReuseAddr}): RpcWebSocketServer =
 
@@ -65,7 +75,7 @@ proc newRpcWebSocketServer*(
   proc processCallback(request: HttpRequest): Future[void] =
     handleRequest(server, request)
 
-  server.wsserver = WSServer.new()
+  server.initWebsocket(compression)
   server.server = HttpServer.create(
     address,
     processCallback,
@@ -77,15 +87,21 @@ proc newRpcWebSocketServer*(
 proc newRpcWebSocketServer*(
   host: string,
   port: Port,
+  compression: bool = false,
   flags: set[ServerFlags] = {ServerFlags.TcpNoDelay,
     ServerFlags.ReuseAddr}): RpcWebSocketServer =
 
-  newRpcWebSocketServer(initTAddress(host, port), flags)
+  newRpcWebSocketServer(
+    initTAddress(host, port),
+    compression,
+    flags
+  )
 
 proc newRpcWebSocketServer*(
   address: TransportAddress,
   tlsPrivateKey: TLSPrivateKey,
   tlsCertificate: TLSCertificate,
+  compression: bool = false,
   flags: set[ServerFlags] = {ServerFlags.TcpNoDelay,
     ServerFlags.ReuseAddr},
   tlsFlags: set[TLSFlags] = {},
@@ -96,7 +112,7 @@ proc newRpcWebSocketServer*(
   proc processCallback(request: HttpRequest): Future[void] =
     handleRequest(server, request)
 
-  server.wsserver = WSServer.new()
+  server.initWebsocket(compression)
   server.server = TlsHttpServer.create(
     address,
     tlsPrivateKey,
@@ -115,6 +131,7 @@ proc newRpcWebSocketServer*(
   port: Port,
   tlsPrivateKey: TLSPrivateKey,
   tlsCertificate: TLSCertificate,
+  compression: bool = false,
   flags: set[ServerFlags] = {ServerFlags.TcpNoDelay,
     ServerFlags.ReuseAddr},
   tlsFlags: set[TLSFlags] = {},
@@ -125,6 +142,7 @@ proc newRpcWebSocketServer*(
     initTAddress(host, port),
     tlsPrivateKey,
     tlsCertificate,
+    compression,
     flags,
     tlsFlags,
     tlsMinVersion,

tests/testserverclient.nim

@@ -55,3 +55,26 @@ suite "Websocket Server/Client RPC":
 
   srv.stop()
   waitFor srv.closeWait()
+
+suite "Websocket Server/Client RPC with Compression":
+  var srv = newRpcWebSocketServer("127.0.0.1", Port(8545), compression = true)
+  var client = newRpcWebSocketClient()
+
+  srv.setupServer()
+  srv.start()
+  waitFor client.connect("ws://127.0.0.1:8545/", compression = true)
+
+  test "Successful RPC call":
+    let r = waitFor client.call("myProc", %[%"abc", %[1, 2, 3, 4]])
+    check r.getStr == "Hello abc data: [1, 2, 3, 4]"
+
+  test "Missing params":
+    expect(CatchableError):
+      discard waitFor client.call("myProc", %[%"abc"])
+
+  test "Error RPC call":
+    expect(CatchableError): # The error type wont be translated
+      discard waitFor client.call("myError", %[%"abc", %[1, 2, 3, 4]])
+
+  srv.stop()
+  waitFor srv.closeWait()