Upgrade Matrix rooms with custom power level override for yourself (aka hijack a room with upgrade)

custom-room-upgrade.sh

#!/bin/bash

set -e

mx_get() {
    curl -s -H "Authorization: Bearer $TOKEN" $HS/$1
}

mx_post() {
    curl -s -X POST -H "Authorization: Bearer $TOKEN" -H "Content-type: application/json" -d "$1" $HS/$2
}

mx_put() {
    curl -s -X PUT -H "Authorization: Bearer $TOKEN" -H "Content-type: application/json" -d "$1" $HS/$2
}

create_room() {
    local data='
    {
        "visibility": "public",
        "creation_content": {
            "predecessor": {
                "event_id": "'$2'",
                "room_id": "'$1'"
            }
        },
        "room_version": "6",
        "power_level_content_override": {
            "users": {
                "'$3'": 9001
            }
        }
    }
    '
    mx_post "$data" _matrix/client/r0/createRoom
}

tombstone() {
    local data='
    {
        "body": "This room has been replaced",
        "replacement_room": "'$2'"
    }
    '
    local quote_room_id=$(echo -n $1 | jq -sRr @uri)
    echo $quote_room_id
    mx_put "$data" _matrix/client/r0/rooms/$quote_room_id/state/m.room.tombstone/
}

echo -n "Give your HS address: "
read HS

echo -n "Give your acccess token: "
read TOKEN

echo -n "Testing connection: "
WHOAMI=$(mx_get _matrix/client/r0/account/whoami)
USER_ID=$(echo $WHOAMI | jq -r .user_id)

echo "Upgrade is being done as $USER_ID, hit enter if correct."
read line

echo -n "Give old room ID: "
read OLD_ROOM_ID

LAST_EVENT=$(mx_get "_matrix/client/r0/sync?filter=%7B%22room%22:%7B%22rooms%22:%5B%22$OLD_ROOM_ID%22%5D%7D%7D" | jq -r '.rooms.join[].timeline.events[-1]')
echo -n "Last event: "
echo $LAST_EVENT | jq
LAST_EVENT_ID=$(echo $LAST_EVENT | jq -r .event_id)
echo "Last event of old room ($OLD_ROOM_ID): $LAST_EVENT_ID"

echo
echo "If this all looks good, hit enter to continue to create new room and tombstone the old"
read line

NEW_ROOM_ID=$(create_room $OLD_ROOM_ID $LAST_EVENT_ID $USER_ID | jq -r .room_id)
tombstone $OLD_ROOM_ID $NEW_ROOM_ID
echo $NEW_ROOM_ID