Handle requests concurrently

.gitignore

@@ -0,0 +1,3 @@
+/client/web/lrpc.js
+/s
+/c

README.md

@@ -18,3 +18,9 @@ This RPC framework supports creating channels to transfer data from server to cl
 When creating a server or client, a `CodecFunc` can be provided. An `io.ReadWriter` is passed into the `CodecFunc` and it returns a `Codec`, which is an interface that contains encode and decode functions with the same signature as `json.Decoder.Decode()` and `json.Encoder.Encode()`.
 
 This allows any codec to be used for the transfer of the data, making it easy to create clients in different languages.
+
+---
+
+### Web Client
+
+Inside `client/web`, there is a web client for lrpc using WebSockets. It is written in ruby (I don't like JS) and translated to human-readable JS using Ruby2JS. With the `bundler` gem installed, cd into `client/web` and run `make`. This will create a new file called `lrpc.js`, which can be used within a browser. It uses `crypto.randomUUID()`, so it must be used on an https site, not http.

client/client.go

@@ -26,7 +26,6 @@ import (
 	"sync"
 
 	"go.arsenm.dev/lrpc/codec"
-	"go.arsenm.dev/lrpc/internal/reflectutil"
 	"go.arsenm.dev/lrpc/internal/types"
 
 	"github.com/gofrs/uuid"
@@ -81,12 +80,17 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 	c.chs[idStr] = make(chan *types.Response, 1)
 	c.chMtx.Unlock()
 
+	argData, err := c.codec.Marshal(arg)
+	if err != nil {
+		return err
+	}
+
 	// Encode request using codec
 	err = c.codec.Encode(types.Request{
 		ID:       idStr,
 		Receiver: rcvr,
 		Method:   method,
-		Arg:      arg,
+		Arg:      argData,
 	})
 	if err != nil {
 		return err
@@ -124,7 +128,11 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 			return ErrReturnNotChannel
 		}
 		// Get channel ID returned in response
-		chID := resp.Return.(string)
+		var chID string
+		err = c.codec.Unmarshal(resp.Return, &chID)
+		if resp.Return == nil {
+			return nil
+		}
 
 		// Create new channel using channel ID
 		c.chMtx.Lock()
@@ -149,21 +157,16 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 					retVal.Close()
 					break
 				}
-				// Get reflect value from channel response
-				rVal := reflect.ValueOf(val.Return)
 
-				// If return value is not the same as the channel
-				if rVal.Type() != chElemType {
-					// Attempt to convert value, skip if impossible
-					newVal, err := reflectutil.Convert(rVal, chElemType)
-					if err != nil {
-						continue
-					}
-					rVal = newVal
+				outVal := reflect.New(chElemType)
+				err = c.codec.Unmarshal(val.Return, outVal.Interface())
+				if err != nil {
+					continue
 				}
+				outVal = outVal.Elem()
 
 				chosen, _, _ := reflect.Select([]reflect.SelectCase{
-					{Dir: reflect.SelectSend, Chan: retVal, Send: rVal},
+					{Dir: reflect.SelectSend, Chan: retVal, Send: outVal},
 					{Dir: reflect.SelectRecv, Chan: ctxDoneVal, Send: reflect.Value{}},
 				})
 				if chosen == 1 {
@@ -179,28 +182,10 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 			}
 		}()
 	} else if resp.Type == types.ResponseTypeNormal {
-		// IF return value is not a pointer, return error
-		if retVal.Kind() != reflect.Ptr {
-			return ErrReturnNotPointer
+		err = c.codec.Unmarshal(resp.Return, ret)
+		if err != nil {
+			return err
 		}
-
-		// Get return type
-		retType := retVal.Type().Elem()
-		// Get refkect value from response
-		rVal := reflect.ValueOf(resp.Return)
-
-		// If types do not match
-		if rVal.Type() != retType {
-			// Attempt to convert types, return error if not possible
-			newVal, err := reflectutil.Convert(rVal, retType)
-			if err != nil {
-				return err
-			}
-			rVal = newVal
-		}
-
-		// Set return value to received value
-		retVal.Elem().Set(rVal)
 	}
 
 	return nil

client/web/Gemfile

@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+
+gem 'ruby2js'

client/web/Gemfile.lock

@@ -0,0 +1,19 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    parser (3.1.2.0)
+      ast (~> 2.4.1)
+    regexp_parser (2.1.1)
+    ruby2js (5.0.1)
+      parser
+      regexp_parser (~> 2.1.1)
+
+PLATFORMS
+  x86_64-linux
+
+DEPENDENCIES
+  ruby2js
+
+BUNDLED WITH
+   2.3.15

client/web/Makefile

@@ -0,0 +1,3 @@
+lrpc.js: convert.rb lrpc.rb
+	bundle install
+	ruby convert.rb > lrpc.js

client/web/convert.rb

@@ -0,0 +1,10 @@
+#!/usr/bin/ruby
+
+require 'ruby2js'
+require 'ruby2js/filter/functions'
+
+puts Ruby2JS.convert(
+    File.read('lrpc.rb'),
+    eslevel: 2016,
+    exclude: [:delete],
+)

client/web/lrpc.rb

@@ -0,0 +1,174 @@
+# LRPCResponseType represents the various types an LRPC
+# response can have.
+LRPCResponseType = {
+  Normal: 0,
+  Error: 1,
+  Channel: 2,
+  ChannelDone: 3,
+}
+
+# LRPCClient represents a client for the LRPC protocol
+# using WebSockets and the JSON codec
+class LRPCClient
+  def initialize(addr)
+    # Set self variables
+    @callMap = Map.new()
+    @enc = TextEncoder.new()
+    @dec = TextDecoder.new()
+    
+    # Create connection to lrpc server
+    @conn = WebSocket.new(addr)
+    @conn.binaryType = "arraybuffer"
+    @conn.onmessage = proc do |msg|
+      # if msg.data is string
+      if msg.data.instance_of? String
+        # Set json to msg.data
+        json = msg.data
+      else
+        # Set json to decoded msg.data
+        json = @dec.decode(msg.data)
+      end
+      # Parse JSON string
+      val = JSON.parse(json)
+      # Get id from callMap
+      fns = @callMap.get(val.ID)
+      # If fns is undefined (key does not exist), and this is
+      # a normal response, return
+      return if !fns && val.Type == LRPCResponseType.Normal
+
+      case val.Type
+      when LRPCResponseType.Normal
+        # If fns is a channel, send the value. Otherwise,
+        # resolve the promise with the value.
+        if fns.isChannel
+          fns.send(val.Return)
+        else
+          fns.resolve(val.Return)
+        end
+      when LRPCResponseType.Channel
+        # Get channel ID from response
+        chID = val.Return
+        # Create new LRPCChannel
+        ch = LRPCChannel.new(self, chID)
+        # Set channel in map
+        @callMap.set(chID, ch)
+        # Resolve promise with channel
+        fns.resolve(ch)
+      when LRPCResponseType.ChannelDone
+        # Close and delete channel
+        fns.close()
+        @callMap.delete(val.ID)
+      when LRPCResponseType.Error
+        # Reject promise with error
+        fns.reject(val.Error)
+      end
+
+      # Delete item from map unless it is a channel
+      @callMap.delete(val.ID) unless fns.isChannel
+    end
+  end
+
+  # call calls a method on the server with the given
+  # argument and returns a promise.
+  def callMethod(rcvr, method, arg)
+    return Promise.new do |resolve, reject|
+      # Get random UUID (this only works with TLS)
+      id = crypto.randomUUID()
+      # Add resolve/reject functions to callMap
+      @callMap.set(id, {
+        resolve: resolve,
+        reject: reject,
+      })
+
+      # Encode data as JSON
+      data = @enc.encode({
+        Receiver: rcvr,
+        Method: method,
+        Arg: arg,
+        ID: id,
+      }.to_json())
+
+      # Send data to lrpc server
+      @conn.send(data.buffer)
+    end
+  end
+
+  # getClient returns an object containing functions
+  # corresponding to registered functions on the given
+  # receiver. It uses the lrpc.Introspect() endpoint
+  # to achieve this.
+  def getObject(rcvr)
+    return Promise.new do |resolve|
+      # Introspect methods on given receiver
+      self.callMethod("lrpc", "Introspect", rcvr).then do |methodDesc|
+        # Create output object
+        out = {}
+        # For each method in description array
+        methodDesc.each do |method|
+          # Create and assign new function to call current method
+          out[method.Name] = proc { |arg| return self.callMethod(rcvr, method.Name, arg) }
+        end
+        # Resolve promise with output promise
+        resolve(out)
+      end
+    end
+  end
+end
+
+# LRPCChannel represents a channel used for lrpc.
+class LRPCChannel
+  def initialize(client, id)
+    # Set self variables
+    @client = client
+    @id = id
+    @closed = false
+    # Set function variables to no-ops
+    @onMessage = proc {|fn|}
+    @onClose = proc {}
+  end
+
+  # isChannel is defined to allow identifying whether
+  # an object is a channel.
+  def isChannel() end
+
+  # send sends a value on the channel. This should not
+  # be called by the consumer of the channel.
+  def send(val)
+    return if @closed
+    fn = @onMessage
+    fn(val)
+  end
+
+  # done cancels the context corresponding to the channel
+  # on the server side and closes the channel.
+  def done()
+    return if @closed
+    @client.callMethod("lrpc", "ChannelDone", @id)
+    self.close()
+    @client._callMap.delete(@id)
+  end
+  
+  # onMessage sets the callback to be called whenever a
+  # message is received. The function should have one parameter
+  # that will be set to the value received. Subsequent calls
+  # will overwrite the callback
+  def onMessage(fn)
+    @onMessage = fn
+  end
+
+  # onClose sets the callback to be called whenever the client
+  # is closed. The function should have no parameters. 
+  # Subsequent calls will overwrite the callback
+  def onClose(fn)
+    @onClose = fn
+  end
+
+  # close closes the channel. This should not be called by the
+  # consumer of the channel. Use done() instead.
+  def close()
+    return if @closed
+    fn = @onClose
+    fn()
+    @closed = true
+  end
+end

codec/codec.go

@@ -19,6 +19,7 @@
 package codec
 
 import (
+	"bytes"
 	"encoding/gob"
 	"encoding/json"
 	"io"
@@ -38,42 +39,76 @@ type CodecFunc func(io.ReadWriter) Codec
 type Codec interface {
 	Encode(val any) error
 	Decode(val any) error
+	Unmarshal(data []byte, v any) error
+	Marshal(v any) ([]byte, error)
 }
 
 // Default is the default CodecFunc
 var Default = Msgpack
 
+type JsonCodec struct {
+	*json.Encoder
+	*json.Decoder
+}
+
+func (JsonCodec) Unmarshal(data []byte, v any) error {
+	return json.Unmarshal(data, v)
+}
+
+func (JsonCodec) Marshal(v any) ([]byte, error) {
+	return json.Marshal(v)
+}
+
 // JSON is a CodecFunc that creates a JSON Codec
 func JSON(rw io.ReadWriter) Codec {
-	type jsonCodec struct {
-		*json.Encoder
-		*json.Decoder
-	}
-	return jsonCodec{
+	return JsonCodec{
 		Encoder: json.NewEncoder(rw),
 		Decoder: json.NewDecoder(rw),
 	}
 }
 
+type MsgpackCodec struct {
+	*msgpack.Encoder
+	*msgpack.Decoder
+}
+
+func (MsgpackCodec) Unmarshal(data []byte, v any) error {
+	return msgpack.Unmarshal(data, v)
+}
+
+func (MsgpackCodec) Marshal(v any) ([]byte, error) {
+	return msgpack.Marshal(v)
+}
+
 // Msgpack is a CodecFunc that creates a Msgpack Codec
 func Msgpack(rw io.ReadWriter) Codec {
-	type msgpackCodec struct {
-		*msgpack.Encoder
-		*msgpack.Decoder
-	}
-	return msgpackCodec{
+	return MsgpackCodec{
 		Encoder: msgpack.NewEncoder(rw),
 		Decoder: msgpack.NewDecoder(rw),
 	}
 }
 
+type GobCodec struct {
+	*gob.Encoder
+	*gob.Decoder
+}
+
+func (GobCodec) Unmarshal(data []byte, v any) error {
+	return gob.NewDecoder(bytes.NewReader(data)).Decode(v)
+}
+
+func (GobCodec) Marshal(v any) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	err := gob.NewEncoder(buf).Encode(v)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
 // Gob is a CodecFunc that creates a Gob Codec
 func Gob(rw io.ReadWriter) Codec {
-	type gobCodec struct {
-		*gob.Encoder
-		*gob.Decoder
-	}
-	return gobCodec{
+	return GobCodec{
 		Encoder: gob.NewEncoder(rw),
 		Decoder: gob.NewDecoder(rw),
 	}

internal/reflectutil/utils.go

@@ -1,186 +0,0 @@
-/*
- *	lrpc allows for clients to call functions on a server remotely.
- *	Copyright (C) 2022 Arsen Musayelyan
- *
- *	This program is free software: you can redistribute it and/or modify
- *	it under the terms of the GNU General Public License as published by
- *	the Free Software Foundation, either version 3 of the License, or
- *	(at your option) any later version.
- *
- *	This program is distributed in the hope that it will be useful,
- *	but WITHOUT ANY WARRANTY; without even the implied warranty of
- *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *	GNU General Public License for more details.
- *
- *	You should have received a copy of the GNU General Public License
- *	along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-package reflectutil
-
-import (
-	"encoding"
-	"fmt"
-	"reflect"
-
-	"github.com/mitchellh/mapstructure"
-)
-
-// <= go1.17 compatibility
-type any = interface{}
-
-// Convert attempts to convert the given value to the given type
-func Convert(in reflect.Value, toType reflect.Type) (reflect.Value, error) {
-	// Get input type
-	inType := in.Type()
-
-	// If input is already the desired type, return
-	if inType == toType {
-		return in, nil
-	}
-
-	// If the output type is a pointer to the input type
-	if reflect.PtrTo(inType) == toType {
-		if in.CanAddr() {
-			// Return pointer to input
-			return in.Addr(), nil
-		}
-
-		inPtrVal := reflect.New(inType)
-		inPtrVal.Elem().Set(in)
-		return inPtrVal, nil
-	}
-
-	// If input is a pointer pointing to the output type
-	if inType.Kind() == reflect.Ptr && inType.Elem() == toType {
-		// Return value being pointed at by input
-		return reflect.Indirect(in), nil
-	}
-
-	// If input can be converted to desired type, convert and return
-	if in.CanConvert(toType) {
-		return in.Convert(toType), nil
-	}
-
-	// Create new value of desired type
-	to := reflect.New(toType).Elem()
-
-	// If type is a pointer
-	if to.Kind() == reflect.Ptr {
-		// Initialize value
-		to.Set(reflect.New(to.Type().Elem()))
-	}
-
-	switch val := in.Interface().(type) {
-	case string:
-		// If desired type satisfies text unmarshaler
-		if u, ok := to.Interface().(encoding.TextUnmarshaler); ok {
-			// Use text unmarshaler to get value
-			err := u.UnmarshalText([]byte(val))
-			if err != nil {
-				return reflect.Value{}, err
-			}
-
-			// Return unmarshaled value
-			return reflect.ValueOf(any(u)), nil
-		}
-	case []byte:
-		// If desired type satisfies binary unmarshaler
-		if u, ok := to.Interface().(encoding.BinaryUnmarshaler); ok {
-			// Use binary unmarshaler to get value
-			err := u.UnmarshalBinary(val)
-			if err != nil {
-				return reflect.Value{}, err
-			}
-
-			// Return unmarshaled value
-			return reflect.ValueOf(any(u)), nil
-		}
-	}
-
-	// If input is a map
-	if in.Kind() == reflect.Map {
-		// Use mapstructure to decode value
-		err := mapstructure.Decode(in.Interface(), to.Addr().Interface())
-		if err == nil {
-			return to, nil
-		}
-	}
-
-	// If input is a slice of any, and output is an array or slice
-	if in.Type() == reflect.TypeOf([]any{}) &&
-		to.Kind() == reflect.Slice || to.Kind() == reflect.Array {
-		// Use ConvertSlice to convert value
-		return reflect.ValueOf(ConvertSlice(
-			in.Interface().([]any),
-			toType,
-		)), nil
-	}
-
-	return to, fmt.Errorf("cannot convert %s to %s", inType, toType)
-}
-
-// ConvertSlice converts []any to an array or slice, as provided
-// in the "to" argument.
-func ConvertSlice(in []any, to reflect.Type) any {
-	// Create new value for output
-	out := reflect.New(to).Elem()
-
-	// Get type of slice elements
-	outType := out.Type().Elem()
-
-	// If output value is a slice
-	if out.Kind() == reflect.Slice {
-		// For every value provided
-		for i := 0; i < len(in); i++ {
-			// Get value of input type
-			inVal := reflect.ValueOf(in[i])
-			// Create new output type
-			outVal := reflect.New(outType).Elem()
-
-			// If types match
-			if inVal.Type() == outType {
-				// Set output value to input value
-				outVal.Set(inVal)
-			} else {
-				newVal, err := Convert(inVal, outType)
-				if err != nil {
-					// Set output value to its zero value
-					outVal.Set(reflect.Zero(outVal.Type()))
-				} else {
-					outVal.Set(newVal)
-				}
-			}
-
-			// Append output value to slice
-			out = reflect.Append(out, outVal)
-		}
-	} else if out.Kind() == reflect.Array && out.Len() == len(in) {
-		//If output type is array and lengths match
-
-		// For every input value
-		for i := 0; i < len(in); i++ {
-			// Get matching output index
-			outVal := out.Index(i)
-			// Get input value
-			inVal := reflect.ValueOf(in[i])
-
-			// If types match
-			if inVal.Type() == outVal.Type() {
-				// Set output value to input value
-				outVal.Set(inVal)
-			} else {
-				newVal, err := Convert(inVal, outType)
-				if err != nil {
-					// Set output value to its zero value
-					outVal.Set(reflect.Zero(outVal.Type()))
-				} else {
-					outVal.Set(newVal)
-				}
-			}
-		}
-	}
-
-	// Return created value
-	return out.Interface()
-}

internal/types/types.go

@@ -26,7 +26,7 @@ type Request struct {
 	ID       string
 	Receiver string
 	Method   string
-	Arg      any
+	Arg      []byte
 }
 
 type ResponseType uint8
@@ -43,5 +43,5 @@ type Response struct {
 	Type   ResponseType
 	ID     string
 	Error  string
-	Return any
+	Return []byte
 }

lrpc_test.go

@@ -149,6 +149,7 @@ func (Channel) Time(ctx *server.Context, interval time.Duration) error {
 			case t := <-tick.C:
 				ch <- t
 			case <-ctx.Done():
+				tick.Stop()
 				close(ch)
 				return
 			}

server/server.go

@@ -28,7 +28,6 @@ import (
 	"sync"
 
 	"go.arsenm.dev/lrpc/codec"
-	"go.arsenm.dev/lrpc/internal/reflectutil"
 	"go.arsenm.dev/lrpc/internal/types"
 	"golang.org/x/net/websocket"
 )
@@ -37,11 +36,11 @@ import (
 type any = interface{}
 
 var (
-	ErrInvalidType        = errors.New("type must be struct or pointer to struct")
-	ErrNoSuchReceiver     = errors.New("no such receiver registered")
-	ErrNoSuchMethod       = errors.New("no such method was found")
-	ErrInvalidMethod      = errors.New("method invalid for lrpc call")
-	ErrUnexpectedArgument = errors.New("argument provided but the function does not accept any arguments")
+	ErrInvalidType    = errors.New("type must be struct or pointer to struct")
+	ErrNoSuchReceiver = errors.New("no such receiver registered")
+	ErrNoSuchMethod   = errors.New("no such method was found")
+	ErrInvalidMethod  = errors.New("method invalid for lrpc call")
+	ErrArgNotProvided = errors.New("method expected an argument, but none was provided")
 )
 
 // Server is an lrpc server
@@ -100,7 +99,7 @@ func (s *Server) Register(v any) error {
 }
 
 // execute runs a method of a registered value
-func (s *Server) execute(pCtx context.Context, typ string, name string, arg any, c codec.Codec) (a any, ctx *Context, err error) {
+func (s *Server) execute(pCtx context.Context, typ string, name string, data []byte, c codec.Codec) (a any, ctx *Context, err error) {
 	// Try to get value from receivers map
 	val, ok := s.rcvrs[typ]
 	if !ok {
@@ -121,29 +120,18 @@ func (s *Server) execute(pCtx context.Context, typ string, name string, arg any,
 	// Get method type
 	mtdType := mtd.Type()
 
-	// Return error if argument provided but isn't expected
-	if mtdType.NumIn() == 1 && arg != nil {
-		return nil, nil, ErrUnexpectedArgument
+	//TODO: if arg not nil but fn has no arg, err
+
+	argType := mtdType.In(1)
+	argVal := reflect.New(argType)
+	arg := argVal.Interface()
+
+	err = c.Unmarshal(data, arg)
+	if err != nil {
+		return nil, nil, err
 	}
 
-	// IF argument is []any
-	anySlice, ok := arg.([]any)
-	if ok {
-		// Convert slice to the method's arg type and
-		// set arg to the newly-converted slice
-		arg = reflectutil.ConvertSlice(anySlice, mtdType.In(1))
-	}
-
-	// Get argument value
-	argVal := reflect.ValueOf(arg)
-	// If argument's type does not match method's argument type
-	if arg != nil && argVal.Type() != mtdType.In(1) {
-		val, err = reflectutil.Convert(argVal, mtdType.In(1))
-		if err != nil {
-			return nil, nil, err
-		}
-		arg = val.Interface()
-	}
+	arg = argVal.Elem().Interface()
 
 	ctx = newContext(pCtx, c)
 	// Get reflect value of context
@@ -152,6 +140,9 @@ func (s *Server) execute(pCtx context.Context, typ string, name string, arg any,
 	switch mtdType.NumOut() {
 	case 0: // If method has no return values
 		if mtdType.NumIn() == 2 {
+			if arg == nil {
+				return nil, nil, ErrArgNotProvided
+			}
 			// Call method with arg, ignore returned value
 			mtd.Call([]reflect.Value{ctxVal, reflect.ValueOf(arg)})
 		} else {
@@ -160,6 +151,10 @@ func (s *Server) execute(pCtx context.Context, typ string, name string, arg any,
 		}
 	case 1: // If method has one return value
 		if mtdType.NumIn() == 2 {
+			if arg == nil {
+				return nil, nil, ErrArgNotProvided
+			}
+
 			// Call method with arg, get returned values
 			out := mtd.Call([]reflect.Value{ctxVal, reflect.ValueOf(arg)})
 
@@ -194,6 +189,10 @@ func (s *Server) execute(pCtx context.Context, typ string, name string, arg any,
 		}
 	case 2: // If method has two return values
 		if mtdType.NumIn() == 2 {
+			if arg == nil {
+				return nil, nil, ErrArgNotProvided
+			}
+
 			// Call method with arg and get returned values
 			out := mtd.Call([]reflect.Value{ctxVal, reflect.ValueOf(arg)})
 
@@ -304,79 +303,103 @@ func (s *Server) handleConn(pCtx context.Context, c codec.Codec) {
 			continue
 		}
 
-		// Execute decoded call
-		val, ctx, err := s.execute(
-			pCtx,
-			call.Receiver,
-			call.Method,
-			call.Arg,
-			c,
-		)
-		if err != nil {
-			s.sendErr(c, call, val, err)
-		} else {
-			// Create response
-			res := types.Response{
-				ID:     call.ID,
-				Return: val,
-			}
+		go func() {
+			// Execute decoded call
+			val, ctx, err := s.execute(
+				pCtx,
+				call.Receiver,
+				call.Method,
+				call.Arg,
+				c,
+			)
+			if err != nil {
+				s.sendErr(c, call, val, err)
+			} else {
+				valData, err := c.Marshal(val)
+				if err != nil {
+					s.sendErr(c, call, val, err)
+					return
+				}
 
-			// If function has created a channel
-			if ctx.isChannel {
-				// Set IsChannel to true
-				res.Type = types.ResponseTypeChannel
-				// Overwrite return value with channel ID
-				res.Return = ctx.channelID
+				// Create response
+				res := types.Response{
+					ID:     call.ID,
+					Return: valData,
+				}
 
-				// Store context in map for future use
-				s.contextsMtx.Lock()
-				s.contexts[ctx.channelID] = ctx
-				s.contextsMtx.Unlock()
-
-				go func() {
-					// For every value received from channel
-					for val := range ctx.channel {
-						codecMtx.Lock()
-						// Encode response using codec
-						c.Encode(types.Response{
-							ID:     ctx.channelID,
-							Return: val,
-						})
-						codecMtx.Unlock()
+				// If function has created a channel
+				if ctx.isChannel {
+					idData, err := c.Marshal(ctx.channelID)
+					if err != nil {
+						s.sendErr(c, call, val, err)
+						return
 					}
 
-					// Cancel context
-					ctx.cancel()
-					// Delete context from map
+					// Set IsChannel to true
+					res.Type = types.ResponseTypeChannel
+					// Overwrite return value with channel ID
+					res.Return = idData
+
+					// Store context in map for future use
 					s.contextsMtx.Lock()
-					delete(s.contexts, ctx.channelID)
+					s.contexts[ctx.channelID] = ctx
 					s.contextsMtx.Unlock()
 
-					codecMtx.Lock()
-					c.Encode(types.Response{
-						Type: types.ResponseTypeChannelDone,
-						ID:   ctx.channelID,
-					})
-					codecMtx.Unlock()
-				}()
+					go func() {
+						// For every value received from channel
+						for val := range ctx.channel {
+							codecMtx.Lock()
+
+							valData, err := c.Marshal(val)
+							if err != nil {
+								continue
+							}
+
+							// Encode response using codec
+							c.Encode(types.Response{
+								ID:     ctx.channelID,
+								Return: valData,
+							})
+
+							codecMtx.Unlock()
+						}
+
+						// Cancel context
+						ctx.cancel()
+						// Delete context from map
+						s.contextsMtx.Lock()
+						delete(s.contexts, ctx.channelID)
+						s.contextsMtx.Unlock()
+
+						codecMtx.Lock()
+						c.Encode(types.Response{
+							Type: types.ResponseTypeChannelDone,
+							ID:   ctx.channelID,
+						})
+						codecMtx.Unlock()
+					}()
+				}
+
+				// Encode response using codec
+				codecMtx.Lock()
+				c.Encode(res)
+				codecMtx.Unlock()
 			}
 
-			// Encode response using codec
-			codecMtx.Lock()
-			c.Encode(res)
-			codecMtx.Unlock()
-		}
+		}()
 	}
 }
 
 // sendErr sends an error response
 func (s *Server) sendErr(c codec.Codec, req types.Request, val any, err error) {
+	valData, _ := c.Marshal(val)
+
 	// Encode error response using codec
 	c.Encode(types.Response{
 		Type:   types.ResponseTypeError,
 		ID:     req.ID,
 		Error:  err.Error(),
-		Return: val,
+		Return: valData,
 	})
 }