Not possible to use bot to create a topic in a private group with topic mode turned on.

[lzhan0121]

When I try to create a new topic in a private group with topic mode enabled using the bot with the following code：

topicName := generateTopicName(message.Chat.Title)
iconColor := getRandomIconColor()
topicParams := &bot.CreateForumTopicParams{
      ChatID:    12345678,
      Name:      topicName,
      IconColor: iconColor,
}
topic, err := b.CreateForumTopic(ctx, topicParams)
if err != nil {
      log.Printf("failed：%v", err)
      errorMsg := &bot.SendMessageParams{
      ChatID: message.Chat.ID,
      Text:   fmt.Sprintf("failed：%v", err),
      }
      b.SendMessage(ctx, errorMsg)
      return
}

The program log returned: Bad request: chat not found

I have set the bot as an administrator of this group and allowed the bot to manage topics.

[lzhan0121]

If the topic group is public, I can successfully create a new topic by using @groupName as the ChatID parameter. But even if the group is public, I cannot successfully create a topic using the group ID.

[negasus]

I don't think it's a library error.

[lzhan0121]

Do you have a solution to this problem?

[negasus]

Its work fine for me

Warning, there is a recursion. Creates a topic on a message.

Testing on private group

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	opts := []bot.Option{
		bot.WithDefaultHandler(handler),
	}

	b, err := bot.New(os.Getenv("EXAMPLE_TELEGRAM_BOT_TOKEN"), opts...)
	if nil != err {
		panic(err)
	}

	b.Start(ctx)
}

func handler(ctx context.Context, b *bot.Bot, update *models.Update) {
	if update.Message == nil {
		return
	}

	chatID := update.Message.Chat.ID

	_, err := b.CreateForumTopic(ctx, &bot.CreateForumTopicParams{
		ChatID:            chatID,
		Name:              "Foo",
		IconColor:         0,
		IconCustomEmojiID: "",
	})
	if nil != err {
		fmt.Printf("Error: %v\n", err)
	}
}

[lzhan0121]

By the way, how do you use update.Message.Chat.ID to represent the ID of a private topic group? I can only use numbers or usernames.

[negasus]

https://github.com/go-telegram/bot/blob/main/methods_params.go#L583
ChatID has any type

[lzhan0121]

What I mean is how to use update.message to get the ID of the private topic group? Do I need to deliberately let the robot send a message in the group?

[negasus]

Another example

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	opts := []bot.Option{
		bot.WithDefaultHandler(handler),
		bot.WithMessageTextHandler("/add", bot.MatchTypeExact, addTopic),
	}

	b, _ := bot.New(os.Getenv("EXAMPLE_TELEGRAM_BOT_TOKEN"), opts...)

	b.Start(ctx)
}

func addTopic(ctx context.Context, b *bot.Bot, update *models.Update) {
	b.CreateForumTopic(ctx, &bot.CreateForumTopicParams{
		ChatID:            update.Message.Chat.ID,
		Name:              "Foo topic",
		IconColor:         0,
		IconCustomEmojiID: "",
	})
}

func handler(ctx context.Context, b *bot.Bot, update *models.Update) {
	if update.MyChatMember == nil {
		return
	}

	fmt.Printf("Chat ID: %d\n", update.MyChatMember.Chat.ID)
}

1. Start the bot
2. Add bot to the group
3. Grant permissions (with can_manage_topics)
4. Send /add

[negasus]

You can store chatID in handler func and create forum topic from bot, without /add command, for example

[lzhan0121]

I run this code:

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	opts := []bot.Option{
		bot.WithDefaultHandler(handler),
		bot.WithMessageTextHandler("/add", bot.MatchTypeExact, addTopic),
	}

	b, err := bot.New("TOKEN", opts...)
	if err != nil {
		log.Println(err)
		log.Panicln(err.Error())
	}

	b.Start(ctx)
}

func addTopic(ctx context.Context, b *bot.Bot, update *models.Update) {
	_, err := b.CreateForumTopic(ctx, &bot.CreateForumTopicParams{
		ChatID:            update.Message.Chat.ID,
		Name:              "Foo topic",
		IconColor:         0,
		IconCustomEmojiID: "",
	})
	if err != nil {
		log.Println(err)
		return
	}
}

func handler(ctx context.Context, b *bot.Bot, update *models.Update) {
	if update.MyChatMember == nil {
		log.Println("ChatMember = nil")
		return
	}

	fmt.Printf("Chat ID: %d\n", update.MyChatMember.Chat.ID)
}

1. The bot is already an administrator of the topic group

2. The bot has can_manage_topic permission

And I sent "/add" to the bot, The log prints:

Would you mind to record an instruction video to show how this work? I will be so gratitude.

[lzhan0121]

Also, have you tried to use the numeric ID of the topic group, such as 12345678, as the parameter of ChatID to successfully create a topic?