I would like to see in game server listings,
I've even taken the time to make the master server list script
outputs to the client as CSV with \r\n line endings
SubmittedIP,SubmittedPort,SubmittedCountryCode,CountryCodeDetected,DetectedIP,Unix Timestamp,SaltedServerHash(Useless to the client),
(I should not that saltedserverhash is generated by the script and is used to look up the server to update its entry in the database)
The server submits heartbeats every 300 seconds or less, or the server is removed from the listing
the listing is here: http://jrwr.co.cc/minetest/masterserver/list.php
to submit a listing, its dead easy, just request this page (cURL comes to mind)
http://jrwr.co.cc/minetest/masterserver/submit.php?action=update&ip=$serverip&port=$serverport&con=$2lettercountycode
(if county code is blank, will replace with detected county code, county code has to be UPPERCASE to be submitted without replacement)
at this time, it will output its CSV format that was submitted to the backend, this can be used for getting information to the server,
Added Error codes, I would just run a check for the first entry to see if "update" was there, if not the script error'd out at you, This script will ping the submitted IP for a Valid server, it must be a minetest server or it will fail, also if submitted ip is put to 127.1.1.13 the script will auto replace the submitted IP to the detected IP allowing servers to detect its outside IPs and if its ping-able
csv list for output of the submit is error/action,submittedip,submittedport,submittedcountrycode,detectedip,detectedcountycode,unixtimestamp,iphash,ping1,ping2,extraerrorcodes
Everything else information wise should be handled by pinging the server and getting its info
Edit: added server ping to prevent spam