How to get channel updates with Telegram robot - telegram

Question

I have searched over Telegram API and Bot API docs for days and it seems there is no direct way for a robot to get notified when there is a new update in a channel say a News channel, Sports channel, etc.
The only thing I came up with was:
A hook returns updates for channel only when the robot is an administrator member:
{
"update_id": 673009340,
"message": {
"message_id": 160,
"from": {
"id": 104911111,
"is_bot": false,
"first_name": "Jason",
"username": "jason",
"language_code": "en-US"
},
"chat": {
"id": -252946114,
"title": "jason",
"type": "group",
"all_members_are_administrators": true
},
"date": 1538468757,
"photo": [
{
"file_id": "AgADBAADFa4xG972mVHqJ-CSWQTFky4lnRoABNEgOrZpJU-OyDgFAAEC",
"file_size": 1795,
"width": 90,
"height": 90
},
{
"file_id": "AgADBAADFa4xG972mVHqJ-CSWQTFky4lnRoABB4OwmYVnYcOyTgFAAEC",
"file_size": 32559,
"width": 320,
"height": 320
},
{
"file_id": "AgADBAADFa4xG972mVHqJ-CSWQTFky4lnRoABIZfLEHYC_NVyjgFAAEC",
"file_size": 159833,
"width": 770,
"height": 770
}
]
}
}
I know that I cannot add a robot to a channel that is not owned by me. But, I can add my username jason to almost any channel. So, is there a way I get my jason_bot to be notified when there's a new update available for jason?

Answer 1

Bots cannot interact with channels unless they are one of the administrators of the channel.
If you want to receive updates from some one else's channels you must act as a client user not a bot. If you join the channel as a member, you can easily receive updates. However, you can check for updates of any public channel without being a member. First, you resolve the channel #username and get (id, access_hash) pair. Then, you can access all messages, and manually check against your database if there is something new.