如何检查用户是否是电报组的成员？

Question

I'd like to use the Telegram API to confirm that a given user is a member of a named group. I can successfully authenticate as the user given their phone number and the code that they get sent, but beyond that I'm pretty lost. I thought I could start with client.contactsSearch with @groupname , but that returns me an empty vector.

I'm using the Kotlogram library from Scala, but it's just a thin wrapper around the MT protocol.

Answer 1

For Bot API, you can use getChatMember method.

The result will contain status for member , left , etc.

Answer 2

This is what I came up with in the end. I don't know whether it's the optimal approach, though.

val PhoneNumber = "+1..."

val app = new TelegramApp(..., "...", "...", "0.0.1", "0.0.1", "en")

class ApiStorage extends TelegramApiStorage {
    ...
}

val client = Kotlogram.getDefaultClient(app, new ApiStorage)

val sentCode = client.authSendCode(false, PhoneNumber, true)
val code = scala.io.StdIn.readLine()
val authorization = client.authSignIn(PhoneNumber, sentCode.getPhoneCodeHash, code)

val self = authorization.getUser.getAsUser

val name = s"${self.getFirstName} ${self.getLastName}"

val userInput = new TLInputUser(self.getId, self.getAccessHash)

client.contactsSearch("@groupname", 100).getChats.toArray.map(_.asInstanceOf[TLChannel]).find(_.getUsername == "groupname") match {
    case Some(channel) =>
        val channelInput = new TLInputChannel(channel.getId, channel.getAccessHash)
        val isMember = Try { client.channelsGetParticipant(channelInput, userInput) } map { _ => true } getOrElse false
        if (isMember) {
            println("Is a member")
        } else {
            println("Is not a member")
        }

    case None =>
        println("Can't find channel @groupname")
}

client.close()