docs(examples): add inline and buttons examples

inline demonstrates AnswerInlineQuery with article results;
buttons demonstrates inline keyboards, callback queries
(AnswerCallback) and editing the message in response.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ernado

examples/buttons/main.go

@@ -0,0 +1,92 @@
+// Command buttons is a bot built on github.com/gotd/botapi that demonstrates
+// inline keyboards and callback queries: /menu shows a keyboard, and tapping a
+// button answers the callback and edits the message.
+//
+// Run it with an MTProto app identity (https://my.telegram.org) and a BotFather
+// token:
+//
+//	APP_ID=12345 APP_HASH=abcdef BOT_TOKEN=123:abc go run ./examples/buttons
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+	"strconv"
+	"time"
+
+	"go.uber.org/zap"
+
+	"github.com/gotd/botapi"
+)
+
+func menu() *botapi.InlineKeyboardMarkup {
+	return &botapi.InlineKeyboardMarkup{
+		InlineKeyboard: [][]botapi.InlineKeyboardButton{
+			{
+				{Text: "👍 Like", CallbackData: "vote:up"},
+				{Text: "👎 Dislike", CallbackData: "vote:down"},
+			},
+			{
+				{Text: "gotd/td", URL: "https://github.com/gotd/td"},
+			},
+		},
+	}
+}
+
+func main() {
+	log, _ := zap.NewDevelopment()
+	defer func() { _ = log.Sync() }()
+
+	appID, err := strconv.Atoi(os.Getenv("APP_ID"))
+	if err != nil {
+		log.Fatal("APP_ID must be a number (see https://my.telegram.org)", zap.Error(err))
+	}
+
+	bot, err := botapi.New(os.Getenv("BOT_TOKEN"), botapi.Options{
+		AppID:   appID,
+		AppHash: os.Getenv("APP_HASH"),
+		Logger:  log,
+	})
+	if err != nil {
+		log.Fatal("Create bot", zap.Error(err))
+	}
+
+	bot.Use(botapi.Recover(), botapi.Timeout(30*time.Second))
+
+	bot.OnCommand("menu", func(c *botapi.Context) error {
+		_, err := c.Reply("How do you like this bot?", botapi.WithReplyMarkup(menu()))
+		return err
+	})
+
+	// Respond to the inline-keyboard taps. The CallbackPrefix predicate filters
+	// to our "vote:" buttons.
+	bot.OnCallbackQuery(func(c *botapi.Context) error {
+		choice := "🤷"
+		switch c.Update.CallbackQuery.Data {
+		case "vote:up":
+			choice = "👍"
+		case "vote:down":
+			choice = "👎"
+		}
+		// Acknowledge the tap (removes the client-side loading state).
+		if err := c.AnswerCallback(botapi.WithCallbackText("Thanks for voting " + choice)); err != nil {
+			return err
+		}
+		// Edit the original message to reflect the choice.
+		msg := c.Update.CallbackQuery.Message
+		if msg == nil {
+			return nil
+		}
+		_, err := c.Bot.EditMessageText(c, botapi.ID(msg.Chat.ID), msg.MessageID, "You voted "+choice)
+		return err
+	}, botapi.CallbackPrefix("vote:"))
+
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	log.Info("Starting buttons bot")
+	if err := bot.Run(ctx); err != nil {
+		log.Fatal("Run", zap.Error(err))
+	}
+}

examples/inline/main.go

@@ -0,0 +1,74 @@
+// Command inline is an inline bot built on github.com/gotd/botapi. Type the
+// bot's @username followed by a query in any chat and it offers article results
+// echoing the query; picking one sends the text.
+//
+// Run it with an MTProto app identity (https://my.telegram.org) and a BotFather
+// token (inline mode must be enabled for the bot via @BotFather):
+//
+//	APP_ID=12345 APP_HASH=abcdef BOT_TOKEN=123:abc go run ./examples/inline
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+	"strconv"
+	"strings"
+
+	"go.uber.org/zap"
+
+	"github.com/gotd/botapi"
+)
+
+func main() {
+	log, _ := zap.NewDevelopment()
+	defer func() { _ = log.Sync() }()
+
+	appID, err := strconv.Atoi(os.Getenv("APP_ID"))
+	if err != nil {
+		log.Fatal("APP_ID must be a number (see https://my.telegram.org)", zap.Error(err))
+	}
+
+	bot, err := botapi.New(os.Getenv("BOT_TOKEN"), botapi.Options{
+		AppID:   appID,
+		AppHash: os.Getenv("APP_HASH"),
+		Logger:  log,
+	})
+	if err != nil {
+		log.Fatal("Create bot", zap.Error(err))
+	}
+
+	bot.OnInlineQuery(func(c *botapi.Context) error {
+		q := strings.TrimSpace(c.Update.InlineQuery.Query)
+		if q == "" {
+			return c.AnswerInline(nil)
+		}
+		results := []botapi.InlineQueryResult{
+			&botapi.InlineQueryResultArticle{
+				ID:          "upper",
+				Title:       "UPPERCASE",
+				Description: strings.ToUpper(q),
+				InputMessageContent: &botapi.InputTextMessageContent{
+					MessageText: strings.ToUpper(q),
+				},
+			},
+			&botapi.InlineQueryResultArticle{
+				ID:          "echo",
+				Title:       "Echo",
+				Description: q,
+				InputMessageContent: &botapi.InputTextMessageContent{
+					MessageText: q,
+				},
+			},
+		}
+		return c.AnswerInline(results, botapi.WithInlineCacheTime(1))
+	})
+
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	log.Info("Starting inline bot")
+	if err := bot.Run(ctx); err != nil {
+		log.Fatal("Run", zap.Error(err))
+	}
+}