动态 Worker 加载器

let id = "foo";

// Get the isolate with the given ID, creating it if no such isolate exists yet.
let worker = env.LOADER.get(id, async () => {
	// If the isolate does not already exist, this callback is invoked to fetch
	// the isolate's Worker code.

	return {
		compatibilityDate: "2025-06-01",

		// Specify the worker's code (module files).
		mainModule: "foo.js",
		modules: {
			"foo.js":
				"export default {\n" +
				"  fetch(req, env, ctx) { return new Response('Hello'); }\n" +
				"}\n",
		},

		// Specify the dynamic Worker's environment (`env`). This is specified
		// as a JavaScript object, exactly as you want it to appear to the
		// child Worker. It can contain basic serializable types as well as
		// Service Bindings (see below).
		env: {
			SOME_ENV_VAR: 123,
		},

		// To block the worker from talking to the internet using `fetch()` or
		// `connect()`, set `globalOutbound` to `null`. You can also set this
		// to any service binding, to have calls be intercepted and redirected
		// to that binding.
		globalOutbound: null,
	};
});

// Now you can get the Worker's entrypoint and send requests to it.
let defaultEntrypoint = worker.getEntrypoint();
await defaultEntrypoint.fetch("http://example.com");

// You can get non-default entrypoints as well, and specify the
// `ctx.props` value to be delivered to the entrypoint.
let someEntrypoint = worker.getEntrypoint("SomeEntrypointClass", {
	props: { someProp: 123 },
});

import { WorkerEntrypoint } from "cloudflare:workers";

export class Greeter extends WorkerEntrypoint {
	fetch(request) {
		return new Response(`Hello, ${this.ctx.props.name}!`);
	}
}

export default {
	async fetch(request, env, ctx) {
		let worker = env.LOADER.get("alice", () => {
			return {
				// Redirect the worker's global outbound to send all requests
				// to the `Greeter` class, filling in `ctx.props.name` with
				// the name "Alice", so that it always responds "Hello, Alice!".
				globalOutbound: ctx.exports.Greeter({ props: { name: "Alice" } }),

				// ... code ...
			};
		});

		return worker.getEntrypoint().fetch(request);
	},
};

import { WorkerEntrypoint } from "cloudflare:workers";

// Implement a binding which can be called by the dynamic Worker.
export class Greeter extends WorkerEntrypoint {
	greet() {
		return `Hello, ${this.ctx.props.name}!`;
	}
}

export default {
	async fetch(request, env, ctx) {
		let worker = env.LOADER.get("alice", () => {
			return {
				env: {
					// Provide a binding which has a method greet() which can be called
					// to receive a greeting. The binding knows the Worker's name.
					GREETER: ctx.exports.Greeter({ props: { name: "Alice" } }),
				},

				// ... code ...
			};
		});

		return worker.getEntrypoint().fetch(request);
	},
};

import { WorkerEntrypoint } from "cloudflare:workers";

export default {
	async fetch(request, env, ctx) {
		let worker = env.LOADER.get("alice", () => {
			return {
				// Send logs, errors, etc. to `LogTailer`. We pass `name` in the
				// `ctx.props` so that `LogTailer` knows what generated the logs.
				// (You can pass anything you want in `props`.)
				tails: [ctx.exports.LogTailer({ props: { name: "alice" } })],

				// ... code ...
			};
		});

		return worker.getEntrypoint().fetch(request);
	},
};

export class LogTailer extends WorkerEntrypoint {
	async tail(events) {
		let name = this.ctx.props.name;

		// Send the logs off to our log endpoint, specifying the worker name in
		// the URL.
		//
		// Note that `events` will always be an array of size 1 in this scenario,
		// describing the event delivered to the dynamically-loaded Worker.
		await fetch(`https://example.com/submit-logs/${name}`, {
			method: "POST",
			body: JSON.stringify(events),
		});
	}
}