MTGo Filters

Filters narrow which updates trigger a handler. They compose with And, Or, and Not.

Using Filters

Pass filters as the second argument to OnMessage and other registration methods:

client.OnMessage(handler, tg.Private)
client.OnMessage(handler, tg.Private.And(tg.Text("hello")))

Built-in Filters

Chat Type

Filter	Matches
Private	DMs (positive ChatID)
Group	Group messages (negative ChatID)
Channel	Channel posts
Direct	Incoming DMs (private + incoming)
Forum	Messages from forum-enabled supergroups
Business	Business connection messages

Message Direction

Filter	Matches
Incoming	Non-outgoing messages
Outgoing	Messages sent by the current user
Me	Outgoing messages (alias)

Content Type

Filter	Matches
Media	Any media attachment
Photo	Photo attachments
Video	Video attachments
Audio	Audio attachments
Voice	Voice notes
VideoNote	Round video notes
Sticker	Stickers
Document	Generic file documents
Animation	GIFs/animations
Contact	Contact cards
Location	Static location pins
LiveLocation	Live updating locations
Venue	Venue info
WebPage	Link previews
Poll	Poll messages
Dice	Dice/animated emoji
Game	HTML5 game attachments
Story	Forwarded stories
PaidMedia	Paid media (Stars)
Invoice	Payment invoices
MediaGroup	Album messages
Caption	Media with caption only

Text Matching

Filter	Matches
Text("hello")	Exact text match
Command("start")	/start command
Regex("\\d+")	Regex pattern match
All	Every update

Sender & Chat

Filter	Matches
User(123, 456)	Specific user IDs
Chat(-100123)	Specific chat IDs
Topic(42)	Specific forum topic
SenderChat(-100)	Specific sender chat
Bot	Messages from bots

Message Properties

Filter	Matches
Reply	Messages that reply to another
Forwarded	Forwarded messages
Mentioned	Messages where you're @mentioned
ViaBot	Messages sent via inline bot
Pinned	Pinned messages
MediaSpoiler	Spoiler-hidden media
Service	Service/system messages

Service Message Filters

Filter	Matches
NewChatMembers	Member join events
LeftChatMember	Member leave events
NewChatTitle	Title change events
NewChatPhoto	Photo change events
DeleteChatPhoto	Photo deletion events
GroupChatCreated	Group creation events
PinnedMessage	Pin notification events

Callback & Inline

Filter	Matches
CallbackData("approve")	Exact callback data match
CallbackRegex("^page_\\d+$")	Regex on callback data
InlineQueryText("search")	Exact inline query text

Composition

Filters compose with three operators:

// AND — both must match
tg.Private.And(tg.Text("hello"))

// OR — either matches
tg.Photo.Or(tg.Video)

// NOT — negate a filter
tg.Bot.Not() // non-bot messages

Chain multiple:

tg.Private.And(tg.Incoming).And(tg.Command("start"))

Custom Filters

Use Create for filters that need client access:

tg.Create(func(c *tg.Client, ctx *tg.Context) bool {
    return isAdmin(c, ctx.Message.FromID)
})

Custom Command Filter

NewCommand creates a command filter with custom prefixes and case sensitivity:

tg.NewCommand(
    []string{"start", "help"},  // commands
    []string{"!", "/"},          // prefixes
    false,                       // case-insensitive
)