Expose http handler (#124)

* Expose the http handler to allow for use in user-defined servers

* Add an example which uses a custom-defined server, and test it

* comments

* Update comments

ext/botmapping.go

@@ -127,42 +127,42 @@ func (m *botMapping) getBotFromURL(urlPath string) (botData, bool) {
 	return bData, ok
 }
 
-// ServeHTTP dispatches the request to the handler whose
-// pattern most closely matches the request URL.
-func (m *botMapping) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if r.RequestURI == "*" {
-		if r.ProtoAtLeast(1, 1) {
-			w.Header().Set("Connection", "close")
+func (m *botMapping) getHandlerFunc(prefix string) func(writer http.ResponseWriter, request *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.RequestURI == "*" {
+			if r.ProtoAtLeast(1, 1) {
+				w.Header().Set("Connection", "close")
+			}
+			w.WriteHeader(http.StatusBadRequest)
+			return
 		}
-		w.WriteHeader(http.StatusBadRequest)
-		return
-	}
 
-	b, ok := m.getBotFromURL(strings.TrimPrefix(r.URL.Path, "/"))
-	if !ok {
-		// If we don't recognise the URL, we return a 404.
-		w.WriteHeader(http.StatusNotFound)
-		return
-	}
+		b, ok := m.getBotFromURL(strings.TrimPrefix(r.URL.Path, prefix))
+		if !ok {
+			// If we don't recognise the URL, we return a 404.
+			w.WriteHeader(http.StatusNotFound)
+			return
+		}
 
-	headerSecret := r.Header.Get("X-Telegram-Bot-Api-Secret-Token")
-	if b.webhookSecret != "" && b.webhookSecret != headerSecret {
-		// Drop any updates from invalid secret tokens.
-		w.WriteHeader(http.StatusUnauthorized)
-		return
-	}
+		headerSecret := r.Header.Get("X-Telegram-Bot-Api-Secret-Token")
+		if b.webhookSecret != "" && b.webhookSecret != headerSecret {
+			// Drop any updates from invalid secret tokens.
+			w.WriteHeader(http.StatusUnauthorized)
+			return
+		}
 
-	bytes, err := io.ReadAll(r.Body)
-	if err != nil {
-		if m.errFunc != nil {
-			m.errFunc(err)
-		} else {
-			m.logf("Failed to read incoming update contents: %s", err.Error())
+		bytes, err := io.ReadAll(r.Body)
+		if err != nil {
+			if m.errFunc != nil {
+				m.errFunc(err)
+			} else {
+				m.logf("Failed to read incoming update contents: %s", err.Error())
+			}
+			w.WriteHeader(http.StatusInternalServerError)
+			return
 		}
-		w.WriteHeader(http.StatusInternalServerError)
-		return
+		b.updateChan <- bytes
 	}
-	b.updateChan <- bytes
 }
 
 func (m *botMapping) logf(format string, args ...interface{}) {

ext/updater.go

@@ -350,6 +350,12 @@ func (u *Updater) SetAllBotWebhooks(domain string, opts *gotgbot.SetWebhookOpts)
 	return nil
 }
 
+// GetHandlerFunc returns the http.HandlerFunc responsible for processing incoming webhook updates.
+// It is provided to allow for an alternative to the StartServer method using a user-defined http server.
+func (u *Updater) GetHandlerFunc(pathPrefix string) http.HandlerFunc {
+	return u.botMapping.getHandlerFunc(pathPrefix)
+}
+
 // StartServer starts the webhook server for all the bots added via AddWebhook.
 // It is recommended to call this BEFORE calling setWebhooks.
 // The opts parameter allows for specifying TLS settings.
@@ -370,7 +376,7 @@ func (u *Updater) StartServer(opts WebhookOpts) error {
 	}
 
 	u.webhookServer = &http.Server{
-		Handler:           &u.botMapping,
+		Handler:           u.GetHandlerFunc("/"),
 		ReadTimeout:       opts.ReadTimeout,
 		ReadHeaderTimeout: opts.ReadHeaderTimeout,
 	}

samples/README.md

@@ -77,3 +77,5 @@ Then, copy-paste the HTTPS URL obtained from ngrok (changes every time you run i
 from the samples/webappBot directory:
 `URL="<your_url_here>" TOKEN="<your_token_here>" go run .`
 Then, simply send /start to your bot, and enjoy your webapp demo.
+
+This example also demonstrates how to use the updater's handler in a user-provided server.

samples/webappBot/main.go

@@ -20,6 +20,8 @@ import (
 // from the samples/webappBot directory:
 // `URL="<your_url_here>" TOKEN="<your_token_here>" go run .`
 // Then, simply send /start to your bot, and enjoy your webapp demo.
+//
+// This example also demonstrates how to use the updater's handler in a user-provided server.
 func main() {
 	// Get token from the environment variable
 	token := os.Getenv("TOKEN")
@@ -33,6 +35,12 @@ func main() {
 		panic("URL environment variable is empty")
 	}
 
+	// Get the webhook secret from the environment variable.
+	webhookSecret := os.Getenv("WEBHOOK_SECRET")
+	if webhookSecret == "" {
+		panic("WEBHOOK_SECRET environment variable is empty")
+	}
+
 	// Create our bot.
 	b, err := gotgbot.NewBot(token, nil)
 	if err != nil {
@@ -52,27 +60,43 @@ func main() {
 
 	// /start command to introduce the bot and send the URL
 	dispatcher.AddHandler(handlers.NewCommand("start", func(b *gotgbot.Bot, ctx *ext.Context) error {
+		// We can wrap commands with anonymous functions to pass in extra variables, like the webapp URL, or other
+		// configuration.
 		return start(b, ctx, webappURL)
 	}))
 
-	// Start receiving (and handling) updates.
-	err = updater.StartPolling(b, &ext.PollingOpts{DropPendingUpdates: true})
+	// We add the bot webhook to our updater, such that we can populate the updater's http.Handler.
+	err = updater.AddWebhook(b, b.Token, ext.WebhookOpts{SecretToken: webhookSecret})
 	if err != nil {
-		panic("failed to start polling: " + err.Error())
+		panic("Failed to add bot webhooks to updater: " + err.Error())
+	}
+
+	// We select a subpath to specify where the updater handler is found on the http.Server.
+	updaterSubpath := "/bots/"
+	err = updater.SetAllBotWebhooks(webappURL+updaterSubpath, &gotgbot.SetWebhookOpts{
+		MaxConnections:     100,
+		DropPendingUpdates: true,
+		SecretToken:        webhookSecret,
+	})
+	if err != nil {
+		panic("Failed to set bot webhooks: " + err.Error())
 	}
-	log.Printf("%s has been started...\n", b.User.Username)
 
 	// Setup new HTTP server mux to handle different paths.
 	mux := http.NewServeMux()
 	// This serves the home page.
 	mux.HandleFunc("/", index(webappURL))
 	// This serves our "validation" API, which checks if the input data is valid.
 	mux.HandleFunc("/validate", validate(token))
+	// This serves the updater's webhook handler.
+	mux.HandleFunc(updaterSubpath, updater.GetHandlerFunc(updaterSubpath))
+
 	server := http.Server{
 		Handler: mux,
 		Addr:    "0.0.0.0:8080",
 	}
 
+	log.Printf("%s has been started...\n", b.User.Username)
 	// Start the webserver displaying the page.
 	// Note: ListenAndServe is a blocking operation, so we don't need to call updater.Idle() here.
 	if err := server.ListenAndServe(); err != nil {

scripts/ci/generate-sample-bot-descriptions.sh

@@ -29,7 +29,7 @@ for d in "${SAMPLES_DIR}"/*; do
   echo "$intro" >>"${README_FILE}"
 
   # Extract all comments before the main function, and dump them in the readme file.
-  description="$(sed -n -e '/package/,/func main/ p' "${d}/main.go" | (grep -E "^//" || true) | sed -e 's:// ::g')"
+  description="$(sed -n -e '/package/,/func main/ p' "${d}/main.go" | (grep -E "^//" || true) | sed -E 's:^// ?::g')"
   if [[ -z "${description}" ]]; then
     echo "!!! no doc comments for ${d} - please add some first."
     exit 1