🚀 Feature Request:RPC Support for Durable Objects in `wrangler dev`

[yawnt]

Describe the solution

When binding a durable object using RPC that was defined in a different worker, it fails with:

Cannot access `MyDurableObject#myMethod` as Durable Object RPC is not yet supported between multiple `wrangler dev` sessions.

This is really useful when using durable objects in combination with wrangler pages dev since, as far as I understand, you cannot deploy a worker from a Pages project.

[petebacondarwin]

Can you try extending the DurableObject class in your code, which may resolve this problem. JS RPC entry points must derive from either DurableObject or WorkerEntrypoint.

[robbertvanginkel]

Extending DurableObject does not fix this. The current behaviour as reported here is part of the test suite on current main, which indicates this would only be supported in the future: e469fb9 /

workers-sdk/fixtures/entrypoints-rpc-tests/tests/entrypoints.spec.ts

Lines 513 to 593 in 26855f3

	test("should support binding to Durable Object in another worker", async ({
	dev,
	}) => {
	// RPC isn't supported in this case yet :(
	await dev({
	"wrangler.toml": dedent`
	name = "bound"
	main = "index.ts"
	[durable_objects]
	bindings = [
	{ name = "OBJECT", class_name = "ThingObject" }
	]
	`,
	"index.ts": dedent`
	import { DurableObject } from "cloudflare:workers";
	export class ThingObject extends DurableObject {
	fetch(request) {
	return new Response(\`\${request.method} \${request.url} \${JSON.stringify(request.cf)}\`);
	}
	get property() {
	return "property:ping";
	}
	method() {
	return "method:ping";
	}
	};
	export default {}; // Required to treat as modules format worker
	`,
	});
	const { url } = await dev({
	"wrangler.toml": dedent`
	name = "entry"
	main = "index.ts"
	[durable_objects]
	bindings = [
	{ name = "OBJECT", class_name = "ThingObject", script_name = "bound" }
	]
	`,
	"index.ts": dedent`
	export default {
	async fetch(request, env, ctx) {
	const id = env.OBJECT.newUniqueId();
	const stub = env.OBJECT.get(id);
	const { pathname } = new URL(request.url);
	if (pathname === "/rpc") {
	const errors = [];
	try { await stub.property; } catch (e) { errors.push(e); }
	try { await stub.method(); } catch (e) { errors.push(e); }
	return Response.json(errors.map(String));
	}
	return stub.fetch("https://placeholder:9999/", {
	method: "POST",
	cf: { thing: true },
	});
	}
	}
	`,
	});
	await waitFor(async () => {
	const response = await fetch(url);
	const text = await response.text();
	// Check protocol, host, and cf preserved
	expect(text).toBe('POST https://placeholder:9999/ {"thing":true}');
	});
	const rpcResponse = await fetch(new URL("/rpc", url));
	const errors = await rpcResponse.json();
	expect(errors).toMatchInlineSnapshot(`
	[
	"Error: Cannot access \`ThingObject#property\` as Durable Object RPC is not yet supported between multiple \`wrangler dev\` sessions.",
	"Error: Cannot access \`ThingObject#method\` as Durable Object RPC is not yet supported between multiple \`wrangler dev\` sessions.",
	]
	`);
	});

[petebacondarwin]

OK thanks for the clarification. I wasn't sure if it had been fixed already. I'll add it to the backlog.

[Chinoman10]

I can also confirm this... been struggling for over a week now, causing project delays because of this...
And even if I deploy I'm unable to test this since I can't bind the DO to the Pages project (it's the only DO that doesn't appear in the bindings list, despite being deployed like all others).

[alexturpin]

Hey folks just chiming in with more support for this! I'm already using cross-worker RPC calls in dev, was surprised to see it didn't work on Durable Objects! Everything else is very lovely to work with, this would be the cherry on top!

[LilaRest]

Hey @alexturpin! Any updates or ETA for that feature?

[alexturpin]

@LilaRest sorry for the confusion, I'm not a Cloudflare employee, was just saying I would also find this very useful!