Environment Capabilities and Channels

Environment capability injection: $send wrapper (the underlying bridge $_send is an internal implementation, held in the init.js closure and not exposed globally), channel descriptions, runtime configuration (plugins/Yeow/runtime/config.yml).

Environment Capability Injection

PluginThread registers a single underlying function in the JS context; init.js holds it in a closure and immediately removes it from the global object — plugin code can only use the wrapped $send:

Function	Signature	Description
$_send(channel, jsonString)	(string, string) => string | null	The sole JS→Java communication entry (internal implementation, not exposed globally)

Supported message channels:

Channel	Purpose	Handling Location
task	Game tasks (requests/get blocks/teleport, etc.)	Main thread scheduler
timer	Timers (setTimeout/setInterval)	Plugin thread Timer thread pool
fs	File system read/write	Plugin thread handles directly
http	HTTP server/client	Plugin thread handles directly
assets	Plugin built-in resource reading	Plugin thread handles directly
service	Service registration/request/subscribe/publish	ServiceManager
debug	Error reporting / heartbeat ping-pong	Plugin thread handles directly
log	Console logging (auto-adds [PluginName] prefix)	Plugin thread handles directly
env	Runtime environment info + microsecond timestamp	Plugin thread handles directly
lifecycle	Lifecycle confirmation (unloadDone)	Plugin thread handles directly

$send Wrapper Layer

init.js wraps $_send into $send(channel, payload), automatically performing JSON conversion. $_send only exists within the init.js closure — plugin code (including dependency packages) that calls $_send directly will receive a ReferenceError:

// $send handles JSON automatically (the only usable entry point for plugins)
$send('task', {type: 'player.get', params: {identifier: 'uuid'}});

Channel Descriptions

task channel — Game tasks, routed through the main thread scheduler:

{
    "type": "player.get",
    "params": {"identifier": "uuid"},
    "cb": "cb_1",         // Async callback ID (optional)
    "priority": "high"     // Priority (optional)
}

Synchronous tasks (no cb) block and wait for the result; asynchronous tasks (with cb) resolve via callback Promise.

timer channel — Replaces $timeout/$interval:

{"type": "timeout", "cb": "cb_1", "delay": 1000}
{"type": "interval", "cb": "cb_2", "delay": 5000}

log channel — Console logging auto-adds the [PluginName] prefix:

console.log('hello');     // → [MyPlugin] hello
console.warn('warning');  // → [MyPlugin] warning

reportError channel — Manually report errors to dev-server source-map resolution:

import { logError } from 'yeow-api';
try { riskyOp(); } catch (e) { logError(e, 'custom context'); }

lifecycle channel — Lifecycle confirmation (used internally by plugins):

$send('lifecycle', {type: 'unloadDone'})    // Confirmation of disable or hot-reload completion

The JS side sends $send('lifecycle') to the Java side for confirmation after the onUnload callback has finished executing. Upon receiving the confirmation, the Java side sets running = false, and the message loop exits naturally.

Wrapper Layer

init.js wraps $_send into a standard JS API:

$_send(channel, jsonString)   ← The only Java-native function (held in init.js closure, not exposed globally)
    ↓
init.js wrapper layer
    ├── $send(channel, object)   ← Automatic JSON conversion (the only usable entry point for plugins)
    ├── console.log/warn/error   ← Auto-adds [pluginName] prefix
    ├── setTimeout / clearTimeout
    ├── setInterval / clearInterval
    ├── fetch                    ← HTTP fetch (Promise)
    └── $hm                      ← Message dispatcher

Runtime Configuration

For the complete reference of plugins/Yeow/runtime/config.yml (auto-generated on first startup), including the Folia section and warning configuration, see Operations - Runtime Configuration; for warning thresholds and dynamic scaling, see Runtime Warning Guide.