How to give access to the telegram bot only to those users who are members of the group?

Question

Telegram

Hello, I have a php bot.
Tell me what needs to be done so that only those who are members of the telegram group have access to the bot, respectively, if the user left the group, access is taken

Answer 1

You need a list of their id's, well, then you just check for the presence of id in the database

Answer 2

To determine the sender use message.from.id
Use the getChatMember method to get the user id.
And just compare. If not, then deny access.

Answer 3

You need "user_id": 14124122,
create a condition, on ===

Answer 4

You add your bot to the group, when the user subscribes / unsubscribes to the channel, you catch the event and enter it in the database or delete it.
In the bot itself, you check if the user is in the database, then he is signed, if he is not there, then he is not signed.