Cloudflare Durable Objects - how to export classes for durable_objects bindings?

[jake-danton]

I am investigating getting nitro working with Cloudflare Durable Objects. In order to do so, you must define bindings in wrangler.toml that maps a name in the Cloudflare env instance to an exported class. Example:

[durable_objects]
bindings = [
  { name = "someObject", class_name = "SomeObject" },
  { name = "someOtherObject", class_name = "SomeOtherObject" }
]

However, when building with the "cloudflare_module" preset, index.mjs only exports the default object with the required fetch method (cloudflareModule). Other classes marked as "export" in the src code are no longer exported in index.mjs.

How do I go about defining these "SomeObject" and "SomeOtherObject" Durable Object classes such that they will be exported as well? Is there a specific directory? A decorator? Preset configuration?

Thanks!
Jake

[jake-danton]

@timhanlon @pi0 I believe both of you have worked on this feature. If you point me in the right direction, I am happy to create a PR with more docs or sample code. Just don't see anything in https://github.com/unjs/nitro/blob/main/src/runtime/entries/cloudflare-module.ts to point me in a useful direction for adding more exports.

[timhanlon]

I dug this out of the Nuxt Discord, worth a shot:

https://discord.com/channels/473401852243869706/897487139888062506/1093592477073670244

https://github.com/nicgene/nuxt-durable-object

[jake-danton]

Awesome! I'll give this approach a try and update as needed. Thanks for the reference and speedy reply!

[Hebilicious]

For most cloudflare-y things (DO, queues, crons ...) with Nitro, you need to use this custom preset approach. The reason it is undocumented is because most users shouldn't rely on "hacky" workarounds, and nitro should provide first class support for these features eventually.

[jake-danton]

Good point. I really enjoy using Nitro, so I will go with the hack for now (it works for my case), but am super excited for full support for this and websockets!

Thanks to all the nitro contributors!

[jake-danton]

For anyone interested in how this looks, here is the simplest form I could get it to.

./nitro.config.ts

export default defineNitroConfig({
  preset: "./preset",
});

./preset/nitro.config.ts:

import { type NitroPreset } from "nitropack";
import { fileURLToPath } from "url";

export default <NitroPreset>{
  extends: "cloudflare-module",
  entry: fileURLToPath(new URL('./entry.ts', import.meta.url)),
};

./preset/entry.ts:

import entry from '#internal/nitro/entries/cloudflare-module'

export * from '../objects'
export default entry

./objects/index.ts

export { FirstDurableObject } from './FirstDurableObject'
export { SecondDurableObject } from './SecondDurableObject'
...

That way, all I have to do to add more durable objects is add a new file in ./objects and add the export in ./objects/index.ts.

And with the export * from '../objects' approach, I should be able to reuse this preset with any Nitro project I need to without additional configuration.

Really appreciate the Nitro team (and unjs in general!) for the flexible apis!

(Now to see if I can get Cloudflare Durable Objects Websockets working too 😁 )