middleware: implement Recover, add docs

bot.go

@@ -37,7 +37,7 @@ func NewBot(pref Settings) (*Bot, error) {
 		Token:   pref.Token,
 		URL:     pref.URL,
 		Poller:  pref.Poller,
-		OnError: pref.OnError,
+		onError: pref.OnError,
 
 		Updates:  make(chan Update, pref.Updates),
 		handlers: make(map[string]HandlerFunc),
@@ -70,7 +70,7 @@ type Bot struct {
 	URL     string
 	Updates chan Update
 	Poller  Poller
-	OnError func(error, Context)
+	onError func(error, Context)
 
 	group       *Group
 	handlers    map[string]HandlerFunc
@@ -149,6 +149,10 @@ type Command struct {
 	Description string `json:"description"`
 }
 
+func (b *Bot) OnError(err error, c Context) {
+	b.onError(err, c)
+}
+
 // Group returns a new group.
 func (b *Bot) Group() *Group {
 	return &Group{b: b}

bot_test.go

@@ -354,7 +354,7 @@ func TestBotOnError(t *testing.T) {
 	}
 
 	var ok bool
-	b.OnError = func(err error, c Context) {
+	b.onError = func(err error, c Context) {
 		assert.Equal(t, b, c.(*nativeContext).b)
 		assert.NotNil(t, err)
 		ok = true

middleware/logger.go

@@ -7,6 +7,8 @@ import (
 	tele "gopkg.in/telebot.v3"
 )
 
+// Logger returns a middleware that logs incoming updates.
+// If no custom logger provided, log.Default() will be used.
 func Logger(logger ...*log.Logger) tele.MiddlewareFunc {
 	var l *log.Logger
 	if len(logger) > 0 {

middleware/middleware.go

@@ -0,0 +1,62 @@
+package middleware
+
+import (
+	"errors"
+
+	tele "gopkg.in/telebot.v3"
+)
+
+// AutoRespond returns a middleware that automatically responds
+// to every callback.
+func AutoRespond() tele.MiddlewareFunc {
+	return func(next tele.HandlerFunc) tele.HandlerFunc {
+		return func(c tele.Context) error {
+			if c.Callback() != nil {
+				defer c.Respond()
+			}
+			return next(c)
+		}
+	}
+}
+
+// IgnoreVia returns a middleware that ignores all the
+// "sent via" messages.
+func IgnoreVia() tele.MiddlewareFunc {
+	return func(next tele.HandlerFunc) tele.HandlerFunc {
+		return func(c tele.Context) error {
+			if msg := c.Message(); msg != nil && msg.Via != nil {
+				return nil
+			}
+			return next(c)
+		}
+	}
+}
+
+// Recover returns a middleware that recovers a panic happened in
+// the handler.
+func Recover(onError ...func(error)) tele.MiddlewareFunc {
+	return func(next tele.HandlerFunc) tele.HandlerFunc {
+		return func(c tele.Context) error {
+			var f func(error)
+			if len(onError) > 0 {
+				f = onError[0]
+			} else {
+				f = func(err error) {
+					c.Bot().OnError(err, nil)
+				}
+			}
+
+			defer func() {
+				if r := recover(); r != nil {
+					if err, ok := r.(error); ok {
+						f(err)
+					} else if s, ok := r.(string); ok {
+						f(errors.New(s))
+					}
+				}
+			}()
+
+			return next(c)
+		}
+	}
+}

middleware/middleware_test.go

@@ -0,0 +1,30 @@
+package middleware
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	tele "gopkg.in/telebot.v3"
+)
+
+var b, _ = tele.NewBot(tele.Settings{Offline: true})
+
+func TestRecover(t *testing.T) {
+	onError := func(err error) {
+		require.Error(t, err, "recover test")
+	}
+
+	h := func(c tele.Context) error {
+		panic("recover test")
+	}
+
+	assert.Panics(t, func() {
+		h(nil)
+	})
+
+	assert.NotPanics(t, func() {
+		Recover(onError)(h)(nil)
+	})
+}

middleware/misc.go

@@ -1,25 +0,0 @@
-package middleware
-
-import tele "gopkg.in/telebot.v3"
-
-func AutoRespond() tele.MiddlewareFunc {
-	return func(next tele.HandlerFunc) tele.HandlerFunc {
-		return func(c tele.Context) error {
-			if c.Callback() != nil {
-				defer c.Respond()
-			}
-			return next(c)
-		}
-	}
-}
-
-func IgnoreVia() tele.MiddlewareFunc {
-	return func(next tele.HandlerFunc) tele.HandlerFunc {
-		return func(c tele.Context) error {
-			if msg := c.Message(); msg != nil && msg.Via != nil {
-				return nil
-			}
-			return next(c)
-		}
-	}
-}

middleware/restrict.go

@@ -2,11 +2,25 @@ package middleware
 
 import tele "gopkg.in/telebot.v3"
 
+// RestrictConfig defines config for Restrict middleware.
 type RestrictConfig struct {
-	Chats   []int64
-	In, Out tele.HandlerFunc
+	// Chats is a list of chats that are going to be affected
+	// by either In or Out function.
+	Chats []int64
+
+	// In defines a function that will be called if the chat
+	// of an update will be found in the Chats list.
+	In tele.HandlerFunc
+
+	// Out defines a function that will be called if the chat
+	// of an update will NOT be found in the Chats list.
+	Out tele.HandlerFunc
 }
 
+// Restrict returns a middleware that handles a list of provided
+// chats with the logic defined by In and Out functions.
+// If the chat is found in the Chats field, In function will be called,
+// otherwise Out function will be called.
 func Restrict(v RestrictConfig) tele.MiddlewareFunc {
 	return func(next tele.HandlerFunc) tele.HandlerFunc {
 		if v.In == nil {
@@ -26,22 +40,26 @@ func Restrict(v RestrictConfig) tele.MiddlewareFunc {
 	}
 }
 
-func Whitelist(chats ...int64) tele.MiddlewareFunc {
+// Blacklist returns a middleware that skips the update for users
+// specified in the chats field.
+func Blacklist(chats ...int64) tele.MiddlewareFunc {
 	return func(next tele.HandlerFunc) tele.HandlerFunc {
 		return Restrict(RestrictConfig{
 			Chats: chats,
-			In:    next,
-			Out:   func(c tele.Context) error { return nil },
+			Out:   next,
+			In:    func(c tele.Context) error { return nil },
 		})(next)
 	}
 }
 
-func Blacklist(chats ...int64) tele.MiddlewareFunc {
+// Whitelist returns a middleware that skips the update for users
+// NOT specified in the chats field.
+func Whitelist(chats ...int64) tele.MiddlewareFunc {
 	return func(next tele.HandlerFunc) tele.HandlerFunc {
 		return Restrict(RestrictConfig{
 			Chats: chats,
-			Out:   next,
-			In:    func(c tele.Context) error { return nil },
+			In:    next,
+			Out:   func(c tele.Context) error { return nil },
 		})(next)
 	}
 }

util.go

@@ -10,28 +10,21 @@ import (
 )
 
 var defaultOnError = func(err error, c Context) {
-	log.Println(c.Update().ID, err)
-}
-
-func (b *Bot) debug(err error) {
-	if b.verbose {
+	if c != nil {
+		log.Println(c.Update().ID, err)
+	} else {
 		log.Println(err)
 	}
 }
 
-func (b *Bot) deferDebug() {
-	if r := recover(); r != nil {
-		if err, ok := r.(error); ok {
-			b.debug(err)
-		} else if str, ok := r.(string); ok {
-			b.debug(fmt.Errorf("%s", str))
-		}
+func (b *Bot) debug(err error) {
+	if b.verbose {
+		b.OnError(err, nil)
 	}
 }
 
 func (b *Bot) runHandler(h HandlerFunc, c Context) {
 	f := func() {
-		defer b.deferDebug()
 		if err := h(c); err != nil {
 			b.OnError(err, c)
 		}
@@ -43,9 +36,9 @@ func (b *Bot) runHandler(h HandlerFunc, c Context) {
 	}
 }
 
-func applyMiddleware(h HandlerFunc, middleware ...MiddlewareFunc) HandlerFunc {
-	for i := len(middleware) - 1; i >= 0; i-- {
-		h = middleware[i](h)
+func applyMiddleware(h HandlerFunc, m ...MiddlewareFunc) HandlerFunc {
+	for i := len(m) - 1; i >= 0; i-- {
+		h = m[i](h)
 	}
 	return h
 }