delete empty old rooms from matrix synapse

smcleanup.sh

#!/bin/bash

# cleanup empty matrix synapse rooms - 
# the matrix synapse admin experience is a total joke, barely above 'idk figure it out, ere are some apis'
# with that said this script will automatically purge all rooms with no users left in them which hang around in the 
# db by default because that totally makes sense

# this is your synapse admin endpoint. in this example its localhost to avoid reverse proxy timeouts/etc
# this is mostly from calling the old v1 delete before which was synchronous and slow.
# beware the nginx etc reverse proxy settings in the docs DO NOT expose admin endpoint
# for nginx reverse proxies, you will want to change your location to eg:
# location ~ ^(/_matrix|/_synapse/client|\/_synapse\/admin) {..  (add |\/_synapse\/admin)
SADMIN="http://localhost:8008/_synapse/admin"

# this is your admin user auth token, you can get this in element by going to 
# quick settings (bottom left gear) -> all settings -> help & about, scroll to bottom to reveal 
AT="<your syt_... token here>"

# temp files to save room list and purge list
RF="rooms.json"
PF="purge.txt"

# if you have more than 500 rooms increase this count or run multiple times
# but be aware the deletes are queued async
curl --header "Authorization: Bearer $AT" "$SADMIN/v1/rooms?limit=500" > $RF
jq '.rooms[] | select(.joined_local_members == 0) | .room_id' < $RF > $PF

LINES=$(cat $PF)
for line in $LINES
do
        rn="${line%\"}"
        rn="${rn#\"}"
	URL="$SADMIN/v2/rooms/$rn"
        echo "deleting room $rn ($URL)"
        # beware: body is required even if empty object.. for very good reasons im sure
        curl --header "Authorization: Bearer $AT" -X DELETE -H "Content-Type: application/json" -d "{}" "$URL"
done