mcpl.py

Minecraft live player location on Overviewer maps using rcon and WebSockets.

The backend code (main.py) is based on ArchmageInc/minecraft-player-locations. The client.js is 'borrowed' from there but might be changed later on by me (see TODOs at the end)

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Usage

First make sure that RCON is enabled on your Minecraft Server. Do this by making sure that in your server.properties:

• rcon.port is set (defaults to 25575 which should be fine)
• rcon.password is set to your preference
• enable-rcon is set to true

WARNING: With great RCON comes great responsibility! Make sure that your rcon port is properly secured, because intruders may gain a lot of power with this access.

with this set, there are 2 ways for using this script:

Docker (recommended)

I build and provide Docker images, which can be used here, but you can also build them yourself using the provided Dockerfile. (Note that next to the mandatory env variables shown here there are also a few optional ones, see below.) Just use docker run -p ws_number:ws_number -e RCON_HOST=mcserver_ip -e RCON_PASSWORD=mcrcon_password -e WS_PORT=ws_number mawalla/mcpl.py

But you can also use docker-compose by using this example docker-compose.yml:

version: '3.3'

services:
  mcpl.py:
    image: mawalla/mcpl.py
    ports:
      - "ws_number:ws_number"
    environment:
      - RCON_HOST=mcserver_ip
      - RCON_PASSWORD=mcrcon_password
      - WS_PORT=ws_number

After this run docker-compose up in the directory containing the .yml

"natively"

(Note that I built it with python 3.9, older/newer versions should work too though.) running it on your machine directly can be done too but needs some pip dependencies first: I recommend doing this in a venv btw.

pip3 install -r requirements.txt

After this you need to set the following env variables (those are mandatory, but there are a few others below):

export RCON_HOST=mcserver_ip export RCON_PASSWORD=mcrcon_password export WS_PORT=ws_number

Then it can be launched by using gunicorn main:app -k flask_sockets.worker -w 1 --threads 1 -b 0.0.0.0:25576

additional env variables

next to the env variables mentioned above, there are also a few more:

• RCON_PORT the RCON port. Defaults to 25575.
• REFRESH_RATE The amount of WebSocket messages sent to clients per second. Defaults to 10. Lowering it reduces bandwidth usage but makes movements on the map choppier. Accordingly increasing it smoothes movements but increases bandwidth usage.

integrating into Overviewer

Finally a few modifications to Overviewer need to be done.

modifying the source file

you need to change into the Overviewer directory (containing the app, not the output). In there you'll find overviewer_core/data/web_assets/index.html. Edit it and you'll find a bunch of <script> tags near the top. Add one more:

<script type="text/javascript" src="client.js"></script>

doing the changes after generating

If you're using a script to automate other stuff anyway, you can also put this somewhere after the overviewer.py statement:

sed -i '14 i <script type="text/javascript" src="client.js"></script>' /path/to/generated/index.html

In case you're using HTTP instead of HTTPS for the Overviewer (or in general), you may wanna modify the socketUrl: line near the top in client.js and replace wss:// with ws:/.

You may also wanna modify that line if your setup differs.

Unfortunately, Overviewer bundles its javascript and trying to put the client.js stuff in there breaks everything, so we need to serve it manually. This can be done by chaining a cp behind the overviwer command, like so:

python3 overviewer.py -c config && cp client.js /path/to/overviewer/out-dir/client.js

(This assumes that client.js is put next to overviewer.py, otherwise point to its path)

done

Now you're set! Enjoy live player locations :D

TODOs

The whole thing ain't perfect yet. There are 3 things that need to be done in the client.js

• Better error handling for nginx errors
  • most notably there is a HTTP 502 response issue that causes lots of loop cycles, bombing the RAM of people with the tab open when the server script isn't running (so make sure that mcpl.py is running when you serve the map or users are gonna have a really bad time)
  • also it should try to reconnect on HTTP 504 responses, otherwise the user has to reload the page for it to work again
• Support for different northdirections
  • if the map has different north directions than upper-left, player positions will be off cause the client assumes it facing always there
• Bukkit/Spigot/PaperMC multiple worlds support
  • most notably the proper handling for overworld/nether/end
  • while there seems to be support for it, this refers to the "default all-in-one world package"