Host API

Extensions talk to the launcher over newline-delimited JSON on stdio (NDJSON), UTF-8 without BOM.

Handshake

Host → extension:

{"type":"hello","host":"1.1.37","dataDir":"C:\\...\\PCL"}

Extension → host:

{"type":"ready","name":"Hello Go"}

After that both directions use {"type": "...", "id": "...", "payload": {...}}. Requests carry an id and must be answered with the same id; the default timeout is 10 seconds.

Message types

Extension → host

Type	Payload	Notes
ready	{name}	Handshake done
notify	{title, text, level}	info / warn / error
log	{text}	Write to the extension log
fs.read	{path}	Needs fs.read
fs.write	{path, data}	Needs fs.write, base64 data
http	{method, url, headers, body}	Needs net
instances	{}	Instance list
versions	{}	Version list
launch	{instance, version}	Needs launch
ui.page	{title, html}	Needs ui
settings.get	{key}	Read a launcher setting
settings.set	{key, value}	Write a launcher setting

Host → extension

Type	Payload	Notes
hello	{host, dataDir, locale}	First message
resp	{ok, data, error}	Response to a request
event	{name, data}	launch.before, launch.after, instance.created, shutdown
ping	{}	Every 30 s; answer with pong

Permission failures look like:

{"type":"resp","id":"7","payload":{"ok":false,"error":"permission denied: net"}}

Go example

package main

import tmlext "github.com/TYWStudio/TML/extensions/sdk/go"

// 业务入口：两个方法都可以留空
type ext struct{}

func (ext) Ready() {
	tmlext.Log("info", "拓展已加载")
	tmlext.Toast("Hello")
}

func (ext) OnEvent(e tmlext.Event) {
	tmlext.Log("info", e.Type)
}

func main() { tmlext.Run(ext{}) }

Rust example

use tml_ext::{Event, Ext, Handler};

struct Ext0;

impl Handler for Ext0 {
    fn ready(&mut self, ext: &mut Ext) {
        ext.log("info", "拓展已加载");
        ext.toast("Hello");
    }

    fn event(&mut self, ext: &mut Ext, ev: Event) {
        ext.log("info", &ev.kind);
    }
}

fn main() { tml_ext::run(Ext0); }

Rules that save you pain

1. Answer hello with ready quickly; do heavy work later.
2. Keep the main loop reading stdin; push long tasks to a worker thread.
3. Handle shutdown and exit on your own.
4. Never print debug output to stdout — it is the protocol channel. Use log or stderr.

Limits

• 1 MiB per message.
• 10 s per request.
• 4 concurrent requests per extension.
• ui.page HTML is sanitised: no <script>, no on* attributes, no external iframes.