place

This project was inspired by r/Place. It is an online shared canvas where you can draw individual pixels.

The project is online at pl.g7kk.com.

How to host a Place

1. You need to compile place.go using the Go compiler.
   Run go build:

   cd ./place
   go build cmd/place/place.go

   alternatively, use go install:

   cd ./place
   go install cmd/place/place.go

2. Run place and set the -root argument to the location of the web/root directory. You can also configure other settings when you run it (see below).

   place -root web/root -port :8080

Other configuration options:

-root string
The directory with the web files. (default "./root")

-count int
The maximum number of connections. (default 64)

-width int
The width to create the canvas. (default 1024)

-height int
The height to create the canvas. (default 1024)

-load string
A png to load as the canvas. (If not set it creates a blank canvas)

-save string
The name to save the canvas. (default "./place.png")

-log string
The log file to write to. (If not set it will log to the command line)

-port string
The port the server listens at. (default ":8080")

-sinterval int
Save interval in seconds. (default 180)

-wl (no value) Enables the whitelist

-whitelist string Path to the whitelist. (default "whitelist.csv")

-loadRecord string Path of the record image to load. (Creates a blank record if not set)

-saveRecord string Path to save the record image to. (default "record.png")

Whitelist

You can optionally add a whitelist. When the whitelist is enabled, only users with a key will be able to draw on the canvas. The server will also keep a record of who placed each pixel.

To use a whitelist, first create a csv document. Each user will have a personal key and an ID that will identify them in the record. The key should be a long string and the ID should be an integer in the range of [1,65535].

I recomend using uuids for the keys. For example:

2237701c-7558-4424-95e1-beee4f6a406a,1
f9e41cf2-0e5d-43f2-bffd-5e2f1aab0a3b,2
4917ba68-41be-4956-93a7-0563257ff182,3
79df0674-f6d5-4556-baad-992e81f72bb2,65535

The pixel colors in the record image correspond to the ID in the whitelist.

When you enable the whitelist using the -wl argument, it will look for a file named "whitelist.csv" in the working directory. But you can set your own path as well:

place -wl -whitelist my_white_list.csv

You can also load an existing record image using -loadRecord, which is similar to -load for loading the canvas

place -load place.png -wl -loadRecord record.csv

If you do not include the -wl argument, the whitelist and record will be ignored.

Maintenance

I recomend setting up some scripts to easily restart the server or rollback the canvas.

Restart the server

This script kills the server and restarts it with the old canvas. This does not reset the canvas.
On my server I have this script set up as a cron job to run nightly to remove any lingering websocket connections.

cd ~/go/src/place/web
pkill place
~/go/bin/place -port :80 -load place.png &>place.log &

Rollback the canvas

This script rolls back the canvas to a previously saved image.

cd ~/go/src/place/web
pkill place
cp place_rollback.png place.png
~/go/bin/place -port :80 -load place.png &>place.log &