Instructional video: https://youtu.be/Bt3ayOVazu0
JuicyRaspberryPie mod provides a "/p" command. When a player issue a "/p" command inside Minecraft, the mod will try to send that command to a command server. the command server interprets incoming commands, then send API request back to Minecraft for it to execute.
JuicyRaspberryPie Forge mod, unlike JuicyRaspberryPie Spigot plugin, does not have a embedded command server. To set up a command server, clone or download https://github.com/wensheng/JuicyRaspberryPie. In JuicyRaspberryPie folder, navigate to bukkit/src/main, copy resources folder to anywhere you like, maybe rename it to something you can remember. Open command window, cd to the folder.
Now you can do interactive programming as described in How to use API on Forge page, you can also start the command server. Open a command(terminal) window and navigate to cmdsvr/python folder, then:
python startsvr.py --apiport=4712 --svrport=4732
(JuicyRaspberryPie Forge mode listens on API port 4712, it expects command server running at port 4732. If you use Spigot, not Forge, you can omit apiport and svrport options)
With the command server turned on, now when you issue "/p list" inside Minecraft, you should see the functions that can be executed. These functions are listed:
cube, flatten, falling_block, rainbow, sphere
Try issue command: "/p cube 3 diamond_block". A 3x3x3 cube of diamond will be created close you in Minecraft. Issuing "/p flatten" will flatten every structure nearby and put a giant square floor under your feet.
Where are these functions come from? Please take a look at examples.py file in side bukkit/src/main/resources/pplugins folder, all functions are defined there.
pplugins is a special folder. The files in this folders are scanned by the command server. Any functions that are decorated with @mcpy or has docstring that starts with "_mcp" will be registered as functions that can be executed by "/p" command.
Go ahead add your own files in this folder then issue "/p update" in Minecraft so your functions in the new files can be picked up and added to "/p" command.
In addition to Python, a javascript command server is provided in JuicyRaspberryPie source, under cmdsvr/javascript folder. To start the Javascript command server, shutdow the python one to free up the port, do a npm install, then:
node index.js
Just as python command server, any files you add to pplugins folder will be picked up by the command server. But unlike python one, each file can only have one exported function.