Small fixes and cleanups (#295)

* fix typos, indicate unused returns

* Add test for publishToClient acl unauthorized

* Add Inline Client as a server option

clients.go

@@ -99,7 +99,7 @@ func (cl *Clients) GetByListener(id string) []*Client {
 type Client struct {
 	Properties   ClientProperties // client properties
 	State        ClientState      // the operational state of the client.
-	Net          ClientConnection // network connection state of the clinet
+	Net          ClientConnection // network connection state of the client
 	ID           string           // the client id.
 	ops          *ops             // ops provides a reference to server ops.
 	sync.RWMutex                  // mutex
@@ -111,7 +111,7 @@ type ClientConnection struct {
 	bconn    *bufio.ReadWriter // a buffered net.Conn for reading packets
 	Remote   string            // the remote address of the client
 	Listener string            // listener id of the client
-	Inline   bool              // client is an inline programmetic client
+	Inline   bool              // if true, the client is the built-in 'inline' embedded client
 }
 
 // ClientProperties contains the properties which define the client behaviour.
@@ -134,7 +134,7 @@ type Will struct {
 	Retain            bool                   // -
 }
 
-// State tracks the state of the client.
+// ClientState tracks the state of the client.
 type ClientState struct {
 	TopicAliases    TopicAliases         // a map of topic aliases
 	stopCause       atomic.Value         // reason for stopping
@@ -311,7 +311,7 @@ func (cl *Client) ResendInflightMessages(force bool) error {
 	return nil
 }
 
-// ClearInflights deletes all inflight messages for the client, eg. for a disconnected user with a clean session.
+// ClearInflights deletes all inflight messages for the client, e.g. for a disconnected user with a clean session.
 func (cl *Client) ClearInflights(now, maximumExpiry int64) []uint16 {
 	deleted := []uint16{}
 	for _, tk := range cl.State.Inflight.GetAll(false) {

clients_test.go

@@ -263,7 +263,7 @@ func TestClientNextPacketIDOverflow(t *testing.T) {
 		cl.State.Inflight.internal[uint16(i)] = packets.Packet{}
 	}
 
-	cl.State.packetID = uint32(cl.ops.options.Capabilities.maximumPacketID - 1)
+	cl.State.packetID = cl.ops.options.Capabilities.maximumPacketID - 1
 	i, err := cl.NextPacketID()
 	require.NoError(t, err)
 	require.Equal(t, cl.ops.options.Capabilities.maximumPacketID, i)
@@ -303,7 +303,7 @@ func TestClientResendInflightMessages(t *testing.T) {
 		err := cl.ResendInflightMessages(true)
 		require.NoError(t, err)
 		time.Sleep(time.Millisecond)
-		w.Close()
+		_ = w.Close()
 	}()
 
 	buf, err := io.ReadAll(r)
@@ -315,7 +315,7 @@ func TestClientResendInflightMessages(t *testing.T) {
 func TestClientResendInflightMessagesWriteFailure(t *testing.T) {
 	pk1 := packets.TPacketData[packets.Publish].Get(packets.TPublishQos1Dup)
 	cl, r, _ := newTestClient()
-	r.Close()
+	_ = r.Close()
 
 	cl.State.Inflight.Set(*pk1.Packet)
 	require.Equal(t, 1, cl.State.Inflight.Len())
@@ -342,8 +342,8 @@ func TestClientReadFixedHeader(t *testing.T) {
 
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{packets.Connect << 4, 0x00})
+		_, _ = r.Write([]byte{packets.Connect << 4, 0x00})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -357,8 +357,8 @@ func TestClientReadFixedHeaderDecodeError(t *testing.T) {
 	defer cl.Stop(errClientStop)
 
 	go func() {
-		r.Write([]byte{packets.Connect<<4 | 1<<1, 0x00, 0x00})
+		_, _ = r.Write([]byte{packets.Connect<<4 | 1<<1, 0x00, 0x00})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -372,8 +372,8 @@ func TestClientReadFixedHeaderPacketOversized(t *testing.T) {
 	defer cl.Stop(errClientStop)
 
 	go func() {
-		r.Write(packets.TPacketData[packets.Publish].Get(packets.TPublishQos1Dup).RawBytes)
+		_, _ = r.Write(packets.TPacketData[packets.Publish].Get(packets.TPublishQos1Dup).RawBytes)
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -387,7 +387,7 @@ func TestClientReadFixedHeaderReadEOF(t *testing.T) {
 	defer cl.Stop(errClientStop)
 
 	go func() {
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -401,8 +401,8 @@ func TestClientReadFixedHeaderNoLengthTerminator(t *testing.T) {
 	defer cl.Stop(errClientStop)
 
 	go func() {
-		r.Write([]byte{packets.Connect << 4, 0xd5, 0x86, 0xf9, 0x9e, 0x01})
+		_, _ = r.Write([]byte{packets.Connect << 4, 0xd5, 0x86, 0xf9, 0x9e, 0x01})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -414,7 +414,7 @@ func TestClientReadOK(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			packets.Publish << 4, 18, // Fixed header
 			0, 5, // Topic Name - LSB+MSB
 			'a', '/', 'b', '/', 'c', // Topic Name
@@ -424,7 +424,7 @@ func TestClientReadOK(t *testing.T) {
 			'd', '/', 'e', '/', 'f', // Topic Name
 			'y', 'e', 'a', 'h', // Payload
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	var pks []packets.Packet
@@ -499,10 +499,10 @@ func TestClientReadFixedHeaderError(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			packets.Publish << 4, 11, // Fixed header
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	cl.Net.bconn = nil
@@ -516,13 +516,13 @@ func TestClientReadReadHandlerErr(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			packets.Publish << 4, 11, // Fixed header
 			0, 5, // Topic Name - LSB+MSB
 			'd', '/', 'e', '/', 'f', // Topic Name
 			'y', 'e', 'a', 'h', // Payload
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	err := cl.Read(func(cl *Client, pk packets.Packet) error {
@@ -536,13 +536,13 @@ func TestClientReadReadPacketOK(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			packets.Publish << 4, 11, // Fixed header
 			0, 5,
 			'd', '/', 'e', '/', 'f',
 			'y', 'e', 'a', 'h',
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	fh := new(packets.FixedHeader)
@@ -573,7 +573,7 @@ func TestClientReadPacket(t *testing.T) {
 		t.Run(tt.Desc, func(t *testing.T) {
 			atomic.StoreInt64(&cl.ops.info.PacketsReceived, 0)
 			go func() {
-				r.Write(tt.RawBytes)
+				_, _ = r.Write(tt.RawBytes)
 			}()
 
 			fh := new(packets.FixedHeader)
@@ -600,7 +600,7 @@ func TestClientReadPacket(t *testing.T) {
 
 func TestClientReadPacketInvalidTypeError(t *testing.T) {
 	cl, _, _ := newTestClient()
-	cl.Net.Conn.Close()
+	_ = cl.Net.Conn.Close()
 	_, err := cl.ReadPacket(&packets.FixedHeader{})
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "invalid packet type")
@@ -624,7 +624,7 @@ func TestClientWritePacket(t *testing.T) {
 		require.NoError(t, err, pkInfo, tt.Case, tt.Desc)
 
 		time.Sleep(2 * time.Millisecond)
-		cl.Net.Conn.Close()
+		_ = cl.Net.Conn.Close()
 
 		require.Equal(t, tt.RawBytes, <-o, pkInfo, tt.Case, tt.Desc)
 
@@ -660,13 +660,13 @@ func TestClientReadPacketReadingError(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			0, 11, // Fixed header
 			0, 5,
 			'd', '/', 'e', '/', 'f',
 			'y', 'e', 'a', 'h',
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	_, err := cl.ReadPacket(&packets.FixedHeader{
@@ -680,13 +680,13 @@ func TestClientReadPacketReadUnknown(t *testing.T) {
 	cl, r, _ := newTestClient()
 	defer cl.Stop(errClientStop)
 	go func() {
-		r.Write([]byte{
+		_, _ = r.Write([]byte{
 			0, 11, // Fixed header
 			0, 5,
 			'd', '/', 'e', '/', 'f',
 			'y', 'e', 'a', 'h',
 		})
-		r.Close()
+		_ = r.Close()
 	}()
 
 	_, err := cl.ReadPacket(&packets.FixedHeader{
@@ -706,7 +706,7 @@ func TestClientWritePacketWriteNoConn(t *testing.T) {
 
 func TestClientWritePacketWriteError(t *testing.T) {
 	cl, _, _ := newTestClient()
-	cl.Net.Conn.Close()
+	_ = cl.Net.Conn.Close()
 
 	err := cl.WritePacket(*pkTable[1].Packet)
 	require.Error(t, err)

cmd/main.go

@@ -60,7 +60,7 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 
 }

examples/auth/basic/main.go

@@ -78,6 +78,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/auth/encoded/main.go

@@ -60,6 +60,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/benchmark/main.go

@@ -47,6 +47,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/debug/main.go

@@ -61,6 +61,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/direct/main.go

@@ -26,7 +26,9 @@ func main() {
 		done <- true
 	}()
 
-	server := mqtt.New(nil)
+	server := mqtt.New(&mqtt.Options{
+		InlineClient: true, // you must enable inline client to use direct publishing and subscribing.
+	})
 	_ = server.AddHook(new(auth.AllowHook), nil)
 
 	// Start the server
@@ -50,12 +52,13 @@ func main() {
 			server.Log.Info("inline client received message from subscription", "client", cl.ID, "subscriptionId", sub.Identifier, "topic", pk.TopicName, "payload", string(pk.Payload))
 		}
 		server.Log.Info("inline client subscribing")
-		server.Subscribe("direct/#", 1, callbackFn)
+		_ = server.Subscribe("direct/#", 1, callbackFn)
-		server.Subscribe("direct/#", 2, callbackFn)
+		_ = server.Subscribe("direct/#", 2, callbackFn)
 	}()
 
-	// There is a shorthand convenience function, Publish, for easily sending
+	// There is a shorthand convenience function, Publish, for easily sending  publish packets if you are not
-	// publish packets if you are not concerned with creating your own packets.
+	// concerned with creating your own packets.  If you want to have more control over your packets, you can
+	//directly inject a packet of any kind into the broker. See examples/hooks/main.go for usage.
 	go func() {
 		for range time.Tick(time.Second * 3) {
 			err := server.Publish("direct/publish", []byte("scheduled message"), false, 0)
@@ -70,23 +73,8 @@ func main() {
 		time.Sleep(time.Second * 10)
 		// Unsubscribe from the same filter to stop receiving messages.
 		server.Log.Info("inline client unsubscribing")
-		server.Unsubscribe("direct/#", 1)
+		_ = server.Unsubscribe("direct/#", 1)
 	}()
-	// If you want to have more control over your packets, you can directly inject a packet of any kind into the broker.
-	//go func() {
-	//	for range time.Tick(time.Second * 5) {
-	//		err := server.InjectPacket(cl, packets.Packet{
-	//			FixedHeader: packets.FixedHeader{
-	//				Type: packets.Publish,
-	//			},
-	//			TopicName: "direct/publish",
-	//			Payload:   []byte("injected scheduled message"),
-	//		})
-	//		if err != nil {
-	//			log.Fatal(err)
-	//		}
-	//	}
-	//}()
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")

examples/hooks/main.go

@@ -83,7 +83,7 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }
 

examples/paho.testing/main.go

@@ -46,7 +46,7 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }
 

examples/persistence/badger/main.go

@@ -53,6 +53,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/persistence/bolt/main.go

@@ -55,6 +55,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/persistence/redis/main.go

@@ -63,6 +63,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/tcp/main.go

@@ -53,6 +53,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/tls/main.go

@@ -112,6 +112,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

examples/websocket/main.go

@@ -42,6 +42,6 @@ func main() {
 
 	<-done
 	server.Log.Warn("caught signal, stopping...")
-	server.Close()
+	_ = server.Close()
 	server.Log.Info("main.go finished")
 }

hooks/auth/ledger.go

@@ -80,8 +80,8 @@ func (r RString) Matches(a string) bool {
 }
 
 // FilterMatches returns true if a filter matches a topic rule.
-func (f RString) FilterMatches(a string) bool {
+func (r RString) FilterMatches(a string) bool {
-	_, ok := MatchTopic(string(f), a)
+	_, ok := MatchTopic(string(r), a)
 	return ok
 }
 
@@ -161,7 +161,7 @@ func (l *Ledger) AuthOk(cl *mqtt.Client, pk packets.Packet) (n int, ok bool) {
 }
 
 // ACLOk returns true if the rules indicate the user is allowed to read or write to
-// a specific filter or topic respectively, based on the write bool.
+// a specific filter or topic respectively, based on the `write` bool.
 func (l *Ledger) ACLOk(cl *mqtt.Client, topic string, write bool) (n int, ok bool) {
 	// If the users map is set, always check for a predefined user first instead
 	// of iterating through global rules.
@@ -209,7 +209,7 @@ func (l *Ledger) ACLOk(cl *mqtt.Client, topic string, write bool) (n int, ok boo
 				}
 			}
 
-			for filter, _ := range rule.Filters {
+			for filter := range rule.Filters {
 				if filter.FilterMatches(topic) {
 					return n, false
 				}

hooks/auth/ledger_test.go

@@ -561,17 +561,17 @@ func TestLedgerUpdate(t *testing.T) {
 		},
 	}
 
-	new := &Ledger{
+	n := &Ledger{
 		Auth: AuthRules{
 			{Remote: "127.0.0.1", Allow: true},
 			{Remote: "192.168.*", Allow: true},
 		},
 	}
 
-	old.Update(new)
+	old.Update(n)
 	require.Len(t, old.Auth, 2)
 	require.Equal(t, RString("192.168.*"), old.Auth[1].Remote)
-	require.NotSame(t, new, old)
+	require.NotSame(t, n, old)
 }
 
 func TestLedgerToJSON(t *testing.T) {

hooks/debug/debug.go

@@ -114,7 +114,7 @@ func (h *Hook) OnQosDropped(cl *mqtt.Client, pk packets.Packet) {
 	h.Log.Debug("inflight dropped", "m", h.packetMeta(pk))
 }
 
-// OnLWTSent is called when a will message has been issued from a disconnecting client.
+// OnLWTSent is called when a Will Message has been issued from a disconnecting client.
 func (h *Hook) OnLWTSent(cl *mqtt.Client, pk packets.Packet) {
 	h.Log.Debug("sent lwt for client", "method", "OnLWTSent", "client", cl.ID)
 }
@@ -136,25 +136,25 @@ func (h *Hook) StoredClients() (v []storage.Client, err error) {
 	return v, nil
 }
 
-// StoredClients is called when the server restores subscriptions from a store.
+// StoredSubscriptions is called when the server restores subscriptions from a store.
 func (h *Hook) StoredSubscriptions() (v []storage.Subscription, err error) {
 	h.Log.Debug("", "method", "StoredSubscriptions")
 	return v, nil
 }
 
-// StoredClients is called when the server restores retained messages from a store.
+// StoredRetainedMessages is called when the server restores retained messages from a store.
 func (h *Hook) StoredRetainedMessages() (v []storage.Message, err error) {
 	h.Log.Debug("", "method", "StoredRetainedMessages")
 	return v, nil
 }
 
-// StoredClients is called when the server restores inflight messages from a store.
+// StoredInflightMessages is called when the server restores inflight messages from a store.
 func (h *Hook) StoredInflightMessages() (v []storage.Message, err error) {
 	h.Log.Debug("", "method", "StoredInflightMessages")
 	return v, nil
 }
 
-// StoredClients is called when the server restores system info from a store.
+// StoredSysInfo is called when the server restores system info from a store.
 func (h *Hook) StoredSysInfo() (v storage.SystemInfo, err error) {
 	h.Log.Debug("", "method", "StoredSysInfo")
 

hooks/storage/badger/badger.go

@@ -128,8 +128,7 @@ func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }
 
-// OnWillSent is called when a client sends a will message and the will message is removed
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
-// from the client record.
 func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }

hooks/storage/badger/badger_test.go

@@ -38,8 +38,8 @@ var (
 )
 
 func teardown(t *testing.T, path string, h *Hook) {
-	h.Stop()
+	_ = h.Stop()
-	h.db.Badger().Close()
+	_ = h.db.Badger().Close()
 	err := os.RemoveAll("./" + strings.Replace(path, "..", "", -1))
 	require.NoError(t, err)
 }

hooks/storage/bolt/bolt.go

@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: MIT
 // SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
 // SPDX-FileContributor: mochi-co
-// package bolt is provided for historical compatibility and may not be actively updated, you should use the badger hook instead.
+
+// Package bolt is provided for historical compatibility and may not be actively updated, you should use the badger hook instead.
 package bolt
 
 import (
@@ -132,8 +133,7 @@ func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }
 
-// OnWillSent is called when a client sends a will message and the will message is removed
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
-// from the client record.
 func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }

hooks/storage/bolt/bolt_test.go

@@ -38,7 +38,7 @@ var (
 )
 
 func teardown(t *testing.T, path string, h *Hook) {
-	h.Stop()
+	_ = h.Stop()
 	err := os.Remove(path)
 	require.NoError(t, err)
 }

hooks/storage/redis/redis.go

@@ -15,7 +15,7 @@ import (
 	"github.com/mochi-mqtt/server/v2/packets"
 	"github.com/mochi-mqtt/server/v2/system"
 
-	redis "github.com/go-redis/redis/v8"
+	"github.com/go-redis/redis/v8"
 )
 
 // defaultAddr is the default address to the redis service.
@@ -134,7 +134,7 @@ func (h *Hook) Init(config any) error {
 	return nil
 }
 
-// Close closes the redis connection.
+// Stop closes the redis connection.
 func (h *Hook) Stop() error {
 	h.Log.Info("disconnecting from redis service")
 
@@ -146,8 +146,7 @@ func (h *Hook) OnSessionEstablished(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }
 
-// OnWillSent is called when a client sends a will message and the will message is removed
+// OnWillSent is called when a client sends a Will Message and the Will Message is removed from the client record.
-// from the client record.
 func (h *Hook) OnWillSent(cl *mqtt.Client, pk packets.Packet) {
 	h.updateClient(cl)
 }

hooks/storage/storage.go

@@ -25,7 +25,7 @@ var (
 	ErrDBFileNotOpen = errors.New("db file not open")
 )
 
-// Client is a storable representation of an mqtt client.
+// Client is a storable representation of an MQTT client.
 type Client struct {
 	Will            ClientWill       `json:"will"`            // will topic and payload data if applicable
 	Properties      ClientProperties `json:"properties"`      // the connect properties for the client
@@ -147,7 +147,7 @@ func (d *Message) ToPacket() packets.Packet {
 	return pk
 }
 
-// Subscription is a storable representation of an mqtt subscription.
+// Subscription is a storable representation of an MQTT subscription.
 type Subscription struct {
 	T                 string `json:"t"`
 	ID                string `json:"id" storm:"id"`

listeners/http_healthcheck.go

@@ -79,9 +79,9 @@ func (l *HTTPHealthCheck) Init(_ *slog.Logger) error {
 // Serve starts listening for new connections and serving responses.
 func (l *HTTPHealthCheck) Serve(establish EstablishFn) {
 	if l.listen.TLSConfig != nil {
-		l.listen.ListenAndServeTLS("", "")
+		_ = l.listen.ListenAndServeTLS("", "")
 	} else {
-		l.listen.ListenAndServe()
+		_ = l.listen.ListenAndServe()
 	}
 }
 
@@ -93,7 +93,7 @@ func (l *HTTPHealthCheck) Close(closeClients CloseFn) {
 	if atomic.CompareAndSwapUint32(&l.end, 0, 1) {
 		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
-		l.listen.Shutdown(ctx)
+		_ = l.listen.Shutdown(ctx)
 	}
 
 	closeClients(l.id)

listeners/http_healthcheck_test.go

@@ -39,7 +39,7 @@ func TestHTTPHealthCheckTLSProtocol(t *testing.T) {
 		TLSConfig: tlsConfigBasic,
 	})
 
-	l.Init(logger)
+	_ = l.Init(logger)
 	require.Equal(t, "https", l.Protocol())
 }
 

listeners/http_sysinfo.go

@@ -81,9 +81,9 @@ func (l *HTTPStats) Init(_ *slog.Logger) error {
 // Serve starts listening for new connections and serving responses.
 func (l *HTTPStats) Serve(establish EstablishFn) {
 	if l.listen.TLSConfig != nil {
-		l.listen.ListenAndServeTLS("", "")
+		_ = l.listen.ListenAndServeTLS("", "")
 	} else {
-		l.listen.ListenAndServe()
+		_ = l.listen.ListenAndServe()
 	}
 }
 
@@ -95,7 +95,7 @@ func (l *HTTPStats) Close(closeClients CloseFn) {
 	if atomic.CompareAndSwapUint32(&l.end, 0, 1) {
 		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
-		l.listen.Shutdown(ctx)
+		_ = l.listen.Shutdown(ctx)
 	}
 
 	closeClients(l.id)
@@ -107,8 +107,8 @@ func (l *HTTPStats) jsonHandler(w http.ResponseWriter, req *http.Request) {
 
 	out, err := json.MarshalIndent(info, "", "\t")
 	if err != nil {
-		io.WriteString(w, err.Error())
+		_, _ = io.WriteString(w, err.Error())
 	}
 
-	w.Write(out)
+	_, _ = w.Write(out)
 }

listeners/http_sysinfo_test.go

@@ -42,7 +42,7 @@ func TestHTTPStatsTLSProtocol(t *testing.T) {
 		TLSConfig: tlsConfigBasic,
 	}, nil)
 
-	l.Init(logger)
+	_ = l.Init(logger)
 	require.Equal(t, "https", l.Protocol())
 }
 

listeners/listeners.go

@@ -22,7 +22,7 @@ type Config struct {
 // EstablishFn is a callback function for establishing new clients.
 type EstablishFn func(id string, c net.Conn) error
 
-// CloseFunc is a callback function for closing all listener clients.
+// CloseFn is a callback function for closing all listener clients.
 type CloseFn func(id string)
 
 // Listener is an interface for network listeners. A network listener listens

listeners/mock_test.go

@@ -16,7 +16,7 @@ func TestMockEstablisher(t *testing.T) {
 	_, w := net.Pipe()
 	err := MockEstablisher("t1", w)
 	require.NoError(t, err)
-	w.Close()
+	_ = w.Close()
 }
 
 func TestNewMockListener(t *testing.T) {
@@ -86,7 +86,7 @@ func TestMockListenerServe(t *testing.T) {
 	require.Equal(t, true, closed)
 	<-o
 
-	mocked.Init(nil)
+	_ = mocked.Init(nil)
 }
 
 func TestMockListenerClose(t *testing.T) {

listeners/net_test.go

@@ -98,7 +98,7 @@ func TestNetEstablishThenEnd(t *testing.T) {
 	}()
 
 	time.Sleep(time.Millisecond)
-	net.Dial("tcp", n.Addr().String())
+	_, _ = net.Dial("tcp", n.Addr().String())
 	require.Equal(t, true, <-established)
 	l.Close(MockCloser)
 	<-o

listeners/tcp_test.go

@@ -39,7 +39,7 @@ func TestTCPProtocolTLS(t *testing.T) {
 		TLSConfig: tlsConfigBasic,
 	})
 
-	l.Init(logger)
+	_ = l.Init(logger)
 	defer l.listen.Close()
 	require.Equal(t, "tcp", l.Protocol())
 }
@@ -124,7 +124,7 @@ func TestTCPEstablishThenEnd(t *testing.T) {
 	}()
 
 	time.Sleep(time.Millisecond)
-	net.Dial("tcp", l.listen.Addr().String())
+	_, _ = net.Dial("tcp", l.listen.Addr().String())
 	require.Equal(t, true, <-established)
 	l.Close(MockCloser)
 	<-o

listeners/unixsock_test.go

@@ -89,7 +89,7 @@ func TestUnixSockEstablishThenEnd(t *testing.T) {
 	}()
 
 	time.Sleep(time.Millisecond)
-	net.Dial("unix", l.listen.Addr().String())
+	_, _ = net.Dial("unix", l.listen.Addr().String())
 	require.Equal(t, true, <-established)
 	l.Close(MockCloser)
 	<-o

listeners/websocket.go

@@ -30,7 +30,7 @@ type Websocket struct { // [MQTT-4.2.0-1]
 	id        string              // the internal id of the listener
 	address   string              // the network address to bind to
 	config    *Config             // configuration values for the listener
-	listen    *http.Server        // an http server for serving websocket connections
+	listen    *http.Server        // a http server for serving websocket connections
 	log       *slog.Logger        // server logger
 	establish EstablishFn         // the server's establish connection handler
 	upgrader  *websocket.Upgrader //  upgrade the incoming http/tcp connection to a websocket compliant connection.
@@ -112,9 +112,9 @@ func (l *Websocket) Serve(establish EstablishFn) {
 	l.establish = establish
 
 	if l.listen.TLSConfig != nil {
-		l.listen.ListenAndServeTLS("", "")
+		_ = l.listen.ListenAndServeTLS("", "")
 	} else {
-		l.listen.ListenAndServe()
+		_ = l.listen.ListenAndServe()
 	}
 }
 
@@ -126,7 +126,7 @@ func (l *Websocket) Close(closeClients CloseFn) {
 	if atomic.CompareAndSwapUint32(&l.end, 0, 1) {
 		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
-		l.listen.Shutdown(ctx)
+		_ = l.listen.Shutdown(ctx)
 	}
 
 	closeClients(l.id)
@@ -137,7 +137,7 @@ type wsConn struct {
 	net.Conn
 	c *websocket.Conn
 
-	// reader for the current message (may be nil)
+	// reader for the current message (can be nil)
 	r io.Reader
 }
 

listeners/websocket_test.go

@@ -37,14 +37,14 @@ func TestWebsocketProtocol(t *testing.T) {
 	require.Equal(t, "ws", l.Protocol())
 }
 
-func TestWebsocketProtocoTLS(t *testing.T) {
+func TestWebsocketProtocolTLS(t *testing.T) {
 	l := NewWebsocket("t1", testAddr, &Config{
 		TLSConfig: tlsConfigBasic,
 	})
 	require.Equal(t, "wss", l.Protocol())
 }
 
-func TestWebsockeInit(t *testing.T) {
+func TestWebsocketInit(t *testing.T) {
 	l := NewWebsocket("t1", testAddr, nil)
 	require.Nil(t, l.listen)
 	err := l.Init(logger)
@@ -54,7 +54,7 @@ func TestWebsockeInit(t *testing.T) {
 
 func TestWebsocketServeAndClose(t *testing.T) {
 	l := NewWebsocket("t1", testAddr, nil)
-	l.Init(logger)
+	_ = l.Init(logger)
 
 	o := make(chan bool)
 	go func(o chan bool) {
@@ -96,7 +96,7 @@ func TestWebsocketServeTLSAndClose(t *testing.T) {
 
 func TestWebsocketUpgrade(t *testing.T) {
 	l := NewWebsocket("t1", testAddr, nil)
-	l.Init(logger)
+	_ = l.Init(logger)
 
 	e := make(chan bool)
 	l.establish = func(id string, c net.Conn) error {
@@ -110,12 +110,12 @@ func TestWebsocketUpgrade(t *testing.T) {
 	require.Equal(t, true, <-e)
 
 	s.Close()
-	ws.Close()
+	_ = ws.Close()
 }
 
 func TestWebsocketConnectionReads(t *testing.T) {
 	l := NewWebsocket("t1", testAddr, nil)
-	l.Init(nil)
+	_ = l.Init(nil)
 
 	recv := make(chan []byte)
 	l.establish = func(id string, c net.Conn) error {
@@ -151,5 +151,5 @@ func TestWebsocketConnectionReads(t *testing.T) {
 	require.Equal(t, pkt, got)
 
 	s.Close()
-	ws.Close()
+	_ = ws.Close()
 }

packets/codes_test.go

@@ -19,7 +19,7 @@ func TestCodesString(t *testing.T) {
 	require.Equal(t, "test", c.String())
 }
 
-func TestCodesErrorr(t *testing.T) {
+func TestCodesError(t *testing.T) {
 	c := Code{
 		Reason: "error",
 		Code:   0x1,

packets/packets.go

@@ -14,7 +14,7 @@ import (
 	"sync"
 )
 
-// All of the valid packet types and their packet identifier.
+// All valid packet types and their packet identifiers.
 const (
 	Reserved       byte = iota // 0 - we use this in packet tests to indicate special-test or all packets.
 	Connect                    // 1
@@ -37,9 +37,9 @@ const (
 
 var (
 	// ErrNoValidPacketAvailable indicates the packet type byte provided does not exist in the mqtt specification.
-	ErrNoValidPacketAvailable error = errors.New("no valid packet available")
+	ErrNoValidPacketAvailable = errors.New("no valid packet available")
 
-	// PacketNames is a map of packet bytes to human readable names, for easier debugging.
+	// PacketNames is a map of packet bytes to human-readable names, for easier debugging.
 	PacketNames = map[byte]string{
 		0:  "Reserved",
 		1:  "Connect",
@@ -272,28 +272,28 @@ func (s Subscription) Merge(n Subscription) Subscription {
 }
 
 // encode encodes a subscription and properties into bytes.
-func (p Subscription) encode() byte {
+func (s Subscription) encode() byte {
 	var flag byte
-	flag |= p.Qos
+	flag |= s.Qos
 
-	if p.NoLocal {
+	if s.NoLocal {
 		flag |= 1 << 2
 	}
 
-	if p.RetainAsPublished {
+	if s.RetainAsPublished {
 		flag |= 1 << 3
 	}
 
-	flag |= p.RetainHandling << 4
+	flag |= s.RetainHandling << 4
 	return flag
 }
 
 // decode decodes subscription bytes into a subscription struct.
-func (p *Subscription) decode(b byte) {
+func (s *Subscription) decode(b byte) {
-	p.Qos = b & 3                      // byte
+	s.Qos = b & 3                      // byte
-	p.NoLocal = 1&(b>>2) > 0           // bool
+	s.NoLocal = 1&(b>>2) > 0           // bool
-	p.RetainAsPublished = 1&(b>>3) > 0 // bool
+	s.RetainAsPublished = 1&(b>>3) > 0 // bool
-	p.RetainHandling = 3 & (b >> 4)    // byte
+	s.RetainHandling = 3 & (b >> 4)    // byte
 }
 
 // ConnectEncode encodes a connect packet.
@@ -343,7 +343,7 @@ func (pk *Packet) ConnectEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -505,7 +505,7 @@ func (pk *Packet) ConnackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 	return nil
 }
 
@@ -548,7 +548,7 @@ func (pk *Packet) DisconnectEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -619,7 +619,7 @@ func (pk *Packet) PublishEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -707,7 +707,7 @@ func (pk *Packet) encodePubAckRelRecComp(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 	return nil
 }
 
@@ -844,7 +844,7 @@ func (pk *Packet) SubackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -901,7 +901,7 @@ func (pk *Packet) SubscribeEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -996,7 +996,7 @@ func (pk *Packet) UnsubackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -1049,7 +1049,7 @@ func (pk *Packet) UnsubscribeEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 
 	return nil
 }
@@ -1109,7 +1109,7 @@ func (pk *Packet) AuthEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	nb.WriteTo(buf)
+	_, _ = nb.WriteTo(buf)
 	return nil
 }
 

packets/packets_test.go

@@ -150,7 +150,7 @@ func TestPacketEncode(t *testing.T) {
 				}
 
 				pk := new(Packet)
-				copier.Copy(pk, wanted.Packet)
+				_ = copier.Copy(pk, wanted.Packet)
 				require.Equal(t, pkt, pk.FixedHeader.Type, pkInfo, pkt, wanted.Desc)
 
 				pk.Mods.AllowResponseInfo = true
@@ -218,7 +218,7 @@ func TestPacketDecode(t *testing.T) {
 
 				pk := &Packet{FixedHeader: FixedHeader{Type: pkt}}
 				pk.Mods.AllowResponseInfo = true
-				pk.FixedHeader.Decode(wanted.RawBytes[0])
+				_ = pk.FixedHeader.Decode(wanted.RawBytes[0])
 				if len(wanted.RawBytes) > 0 {
 					pk.FixedHeader.Remaining = int(wanted.RawBytes[1])
 				}

packets/properties.go

@@ -77,7 +77,7 @@ type UserProperty struct { // [MQTT-1.5.7-1]
 	Val string `json:"v"`
 }
 
-// Properties contains all of the mqtt v5 properties available for a packet.
+// Properties contains all mqtt v5 properties available for a packet.
 // Some properties have valid values of 0 or not-present. In this case, we opt for
 // property flags to indicate the usage of property.
 // Refer to mqtt v5 2.2.2.2 Property spec for more information.
@@ -355,7 +355,7 @@ func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
 	}
 
 	encodeLength(b, int64(buf.Len()))
-	buf.WriteTo(b) // [MQTT-3.1.3-10]
+	_, _ = buf.WriteTo(b) // [MQTT-3.1.3-10]
 }
 
 // Decode decodes property bytes into a properties struct.

packets/tpackets.go

@@ -40,7 +40,6 @@ const (
 	TConnectMqtt5
 	TConnectMqtt5LWT
 	TConnectClean
-	TConnectCleanLWT
 	TConnectUserPass
 	TConnectUserPassLWT
 	TConnectMalProtocolName
@@ -61,7 +60,6 @@ const (
 	TConnectInvalidProtocolVersion2
 	TConnectInvalidReservedBit
 	TConnectInvalidClientIDTooLong
-	TConnectInvalidPasswordNoUsername
 	TConnectInvalidFlagNoUsername
 	TConnectInvalidFlagNoPassword
 	TConnectInvalidUsernameNoFlag
@@ -186,7 +184,6 @@ const (
 	TUnsubscribe
 	TUnsubscribeMany
 	TUnsubscribeMqtt5
-	TUnsubscribeDropProperties
 	TUnsubscribeMalPacketID
 	TUnsubscribeMalTopicName
 	TUnsubscribeMalProperties
@@ -204,7 +201,6 @@ const (
 	TDisconnect
 	TDisconnectTakeover
 	TDisconnectMqtt5
-	TDisconnectNormalMqtt5
 	TDisconnectSecondConnect
 	TDisconnectReceiveMaximum
 	TDisconnectDropProperties

server.go

@@ -2,7 +2,7 @@
 // SPDX-FileCopyrightText: 2022 mochi-mqtt, mochi-co
 // SPDX-FileContributor: mochi-co
 
-// package mqtt provides a high performance, fully compliant MQTT v5 broker server with v3.1.1 backward compatibility.
+// Package mqtt provides a high performance, fully compliant MQTT v5 broker server with v3.1.1 backward compatibility.
 package mqtt
 
 import (
@@ -26,7 +26,7 @@ import (
 )
 
 const (
-	Version                       = "2.3.0" // the current server version.
+	Version                       = "2.4.0" // the current server version.
 	defaultSysTopicInterval int64 = 1       // the interval between $SYS topic publishes
 	LocalListener                 = "local"
 	InlineClientId                = "inline"
@@ -38,7 +38,7 @@ var (
 		MaximumSessionExpiryInterval: math.MaxUint32, // maximum number of seconds to keep disconnected sessions
 		MaximumMessageExpiryInterval: 60 * 60 * 24,   // maximum message expiry if message expiry is 0 or over
 		ReceiveMaximum:               1024,           // maximum number of concurrent qos messages per client
-		MaximumQos:                   2,              // maxmimum qos value available to clients
+		MaximumQos:                   2,              // maximum qos value available to clients
 		RetainAvailable:              1,              // retain messages is available
 		MaximumPacketSize:            0,              // no maximum packet size
 		TopicAliasMaximum:            math.MaxUint16, // maximum topic alias value
@@ -49,8 +49,9 @@ var (
 		MaximumClientWritesPending:   1024 * 8,       // maximum number of pending message writes for a client
 	}
 
-	ErrListenerIDExists = errors.New("listener id already exists") // a listener with the same id already exists.
+	ErrListenerIDExists       = errors.New("listener id already exists")                               // a listener with the same id already exists
 	ErrConnectionClosed       = errors.New("connection not open")                                      // connection is closed
+	ErrInlineClientNotEnabled = errors.New("please set Options.InlineClient=true to use this feature") // inline client is not enabled by default
 )
 
 // Capabilities indicates the capabilities and features provided by the server.
@@ -106,6 +107,10 @@ type Options struct {
 
 	// SysTopicResendInterval specifies the interval between $SYS topic updates in seconds.
 	SysTopicResendInterval int64
+
+	// Enable Inline client to allow direct subscribing and publishing from the parent codebase,
+	// with negligible performance difference (disabled by default to prevent confusion in statistics).
+	InlineClient bool
 }
 
 // Server is an MQTT broker server. It should be created with server.New()
@@ -119,8 +124,8 @@ type Server struct {
 	loop         *loop                // loop contains tickers for the system event loop
 	done         chan bool            // indicate that the server is ending
 	Log          *slog.Logger         // minimal no-alloc logger
-	hooks        *Hooks               // hooks contains hooks for extra functionality such as auth and persistent storage.
+	hooks        *Hooks               // hooks contains hooks for extra functionality such as auth and persistent storage
-	inlineClient *Client              // inlineClient is a special client used for inline subscriptions and inline Publish.
+	inlineClient *Client              // inlineClient is a special client used for inline subscriptions and inline Publish
 }
 
 // loop contains interval tickers for the system events loop.
@@ -129,7 +134,7 @@ type loop struct {
 	clientExpiry   *time.Ticker     // interval ticker for cleaning expired clients
 	inflightExpiry *time.Ticker     // interval ticker for cleaning up expired inflight messages
 	retainedExpiry *time.Ticker     // interval ticker for cleaning retained messages
-	willDelaySend  *time.Ticker     // interval ticker for sending will messages with a delay
+	willDelaySend  *time.Ticker     // interval ticker for sending Will Messages with a delay
 	willDelayed    *packets.Packets // activate LWT packets which will be sent after a delay
 }
 
@@ -173,8 +178,11 @@ func New(opts *Options) *Server {
 			Log: opts.Logger,
 		},
 	}
+
+	if s.Options.InlineClient {
 		s.inlineClient = s.NewClient(nil, LocalListener, InlineClientId, true)
 		s.Clients.Add(s.inlineClient)
+	}
 
 	return s
 }
@@ -426,7 +434,7 @@ func (s *Server) receivePacket(cl *Client, pk packets.Packet) error {
 		if code, ok := err.(packets.Code); ok &&
 			cl.Properties.ProtocolVersion == 5 &&
 			code.Code >= packets.ErrUnspecifiedError.Code {
-			s.DisconnectClient(cl, code)
+			_ = s.DisconnectClient(cl, code)
 		}
 
 		s.Log.Warn("error processing packet", "error", err, "client", cl.ID, "listener", cl.Net.Listener, "pk", pk)
@@ -464,7 +472,7 @@ func (s *Server) validateConnect(cl *Client, pk packets.Packet) packets.Code {
 // session is abandoned.
 func (s *Server) inheritClientSession(pk packets.Packet, cl *Client) bool {
 	if existing, ok := s.Clients.Get(pk.Connect.ClientIdentifier); ok {
-		s.DisconnectClient(existing, packets.ErrSessionTakenOver)                                       // [MQTT-3.1.4-3]
+		_ = s.DisconnectClient(existing, packets.ErrSessionTakenOver)                                   // [MQTT-3.1.4-3]
 		if pk.Connect.Clean || (existing.Properties.Clean && existing.Properties.ProtocolVersion < 5) { // [MQTT-3.1.2-4] [MQTT-3.1.4-4]
 			s.UnsubscribeClient(existing)
 			existing.ClearInflights(math.MaxInt64, 0)
@@ -649,11 +657,15 @@ func (s *Server) processPingreq(cl *Client, _ packets.Packet) error {
 	})
 }
 
-// Publish publishes a publish packet into the broker as if it were sent from the speicfied client.
+// Publish publishes a publish packet into the broker as if it were sent from the specified client.
 // This is a convenience function which wraps InjectPacket. As such, this method can publish packets
 // to any topic (including $SYS) and bypass ACL checks. The qos byte is used for limiting the
 // outbound qos (mqtt v5) rather than issuing to the broker (we assume qos 2 complete).
 func (s *Server) Publish(topic string, payload []byte, retain bool, qos byte) error {
+	if !s.Options.InlineClient {
+		return ErrInlineClientNotEnabled
+	}
+
 	return s.InjectPacket(s.inlineClient, packets.Packet{
 		FixedHeader: packets.FixedHeader{
 			Type:   packets.Publish,
@@ -669,11 +681,18 @@ func (s *Server) Publish(topic string, payload []byte, retain bool, qos byte) er
 // Subscribe adds an inline subscription for the specified topic filter and subscription identifier
 // with the provided handler function.
 func (s *Server) Subscribe(filter string, subscriptionId int, handler InlineSubFn) error {
+	if !s.Options.InlineClient {
+		return ErrInlineClientNotEnabled
+	}
+
 	if handler == nil {
 		return packets.ErrInlineSubscriptionHandlerInvalid
-	} else if !IsValidFilter(filter, false) {
+	}
+
+	if !IsValidFilter(filter, false) {
 		return packets.ErrTopicFilterInvalid
 	}
+
 	subscription := packets.Subscription{
 		Identifier: subscriptionId,
 		Filter:     filter,
@@ -704,6 +723,10 @@ func (s *Server) Subscribe(filter string, subscriptionId int, handler InlineSubF
 // It allows you to unsubscribe a specific subscription from the internal subscription
 // associated with the given topic filter.
 func (s *Server) Unsubscribe(filter string, subscriptionId int) error {
+	if !s.Options.InlineClient {
+		return ErrInlineClientNotEnabled
+	}
+
 	if !IsValidFilter(filter, false) {
 		return packets.ErrTopicFilterInvalid
 	}
@@ -761,12 +784,12 @@ func (s *Server) processPublish(cl *Client, pk packets.Packet) error {
 			return s.DisconnectClient(cl, packets.ErrNotAuthorized)
 		}
 
-		if pk.FixedHeader.Qos == 1 {
+		ackType := packets.Puback
-			ack := s.buildAck(pk.PacketID, packets.Puback, 0, pk.Properties, packets.ErrNotAuthorized)
+		if pk.FixedHeader.Qos == 2 {
-			return cl.WritePacket(ack)
+			ackType = packets.Pubrec
 		}
 
-		ack := s.buildAck(pk.PacketID, packets.Pubrec, 0, pk.Properties, packets.ErrNotAuthorized)
+		ack := s.buildAck(pk.PacketID, ackType, 0, pk.Properties, packets.ErrNotAuthorized)
 		return cl.WritePacket(ack)
 	}
 
@@ -790,7 +813,7 @@ func (s *Server) processPublish(cl *Client, pk packets.Packet) error {
 	}
 
 	if pk.FixedHeader.Qos > s.Options.Capabilities.MaximumQos {
-		pk.FixedHeader.Qos = s.Options.Capabilities.MaximumQos // [MQTT-3.2.2-9] Reduce Qos based on server max qos capability
+		pk.FixedHeader.Qos = s.Options.Capabilities.MaximumQos // [MQTT-3.2.2-9] Reduce qos based on server max qos capability
 	}
 
 	pkx, err := s.hooks.OnPublish(cl, pk)
@@ -1373,7 +1396,7 @@ func (s *Server) Close() error {
 func (s *Server) closeListenerClients(listener string) {
 	clients := s.Clients.GetByListener(listener)
 	for _, cl := range clients {
-		s.DisconnectClient(cl, packets.ErrServerShuttingDown)
+		_ = s.DisconnectClient(cl, packets.ErrServerShuttingDown)
 	}
 }
 

topics.go

@@ -705,7 +705,7 @@ func IsSharedFilter(filter string) bool {
 
 // IsValidFilter returns true if the filter is valid.
 func IsValidFilter(filter string, forPublish bool) bool {
-	if !forPublish && len(filter) == 0 { // publishing can accept zero-length topic filter if topic alias exists, so we don't enforce for publihs.
+	if !forPublish && len(filter) == 0 { // publishing can accept zero-length topic filter if topic alias exists, so we don't enforce for publish.
 		return false // [MQTT-4.7.3-1]
 	}