feat(deploy): add cloudflare context to platform object

[rmarscher]

Example usage from a server component:

import { unstable_getPlatformObject } from 'waku/server';

const getData = async () => {
  const { env, executionCtx } = unstable_getPlatformObject() as { env: Env; executionCtx: ExecutionContext };
  executionCtx?.waitUntil(
    new Promise<void>((resolve) => {
      console.log("Waiting for 5 seconds")
      setTimeout(() => {
        console.log("OK, done waiting")
        resolve()
      }, 5000)
    }),
  )
  const { results } = await env.DB.prepare(
    "SELECT * FROM users WHERE user_id = ?",
  )
    .bind(userId)
    .all();
  return results;
};

Server console output:

Waiting for 5 seconds
[wrangler:inf] GET /about 200 OK (30ms)
[wrangler:inf] GET /assets/jsx-runtime-BjG_zV1W.js 304 Not Modified (6ms)
[wrangler:inf] GET /assets/index-CbskofAj.js 304 Not Modified (7ms)
[wrangler:inf] GET /assets/_layout-Shb4QlRw.css 304 Not Modified (9ms)
[wrangler:inf] GET /assets/rsc2-c69df7b3e.js 200 OK (11ms)
[wrangler:inf] GET /assets/client-kczTGGZ_.js 304 Not Modified (16ms)
[wrangler:inf] GET /assets/indexHtml-DCalQi_d.js 304 Not Modified (18ms)
[wrangler:inf] GET /assets/client-CMyJdxTj.js 304 Not Modified (21ms)
[wrangler:inf] GET /assets/rsc0-ba005381c.js 304 Not Modified (4ms)
[wrangler:inf] GET /images/favicon.png 304 Not Modified (3ms)
OK, done waiting

The page was already sent to the client and loaded while the promise was still executing.

It is necessary to cast the Cloudflare types. See https://developers.cloudflare.com/workers/languages/typescript/#generate-types-that-match-your-workers-configuration-experimental for info on generating types for your project.

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Name	Status	Preview	Updated (UTC)
waku	✅ Ready (Inspect)	Visit Preview	Sep 14, 2024 11:02pm

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[dai-shi]

Using the getEnv API until #827 is resolved

#860 was my answer. Can you try it? getEnv is for strings.

[rmarscher]

I'm getting close. I just need to do testing on this latest implementation. Does https://github.com/dai-shi/waku/pull/872/files#diff-cd6a8e530f81183dc69573add03d2338dfb64976b74eec5eb387e66a713e6522R45-R53 look good? I'm trying to remove non-string vars that Cloudflare puts in env before passing to the runner.

In addition to the bindings, I found that cloudflare allows JSON in env vars: https://developers.cloudflare.com/workers/configuration/environment-variables/#add-environment-variables-via-wrangler

[rmarscher]

There are some typescript issues due to differences in workerd built-in types like Request/Response but I worked around them with casting.

[dai-shi]

It might not change anything real, but for consistency. (Will be refactored anyway.)

Suggested change

	import { unstable_getPlatformObject } from 'waku/server';
	import { unstable_getPlatformObject } from '../../server.js';

[dai-shi]

This is confusing. So:

Suggested change

	fetch,
	fetch as CloudflareFetch,

[dai-shi]

This is not good.
The platform object is something stable all the time. It shouldn't change for each request.
unstable_getCustomContext is for each request. And, the hono context is already exposed. #852

[dai-shi]

I believe asserting types is more appropriate than annotating types, because it never be type safe.

[dai-shi]

Unless we do this, this PR doesn't provide any more capability than #852.

[rmarscher]

@dai-shi Thank you reviewing the PR. You mentioned the context API before and I saw #852 but I hadn't found unstable_getCustomContext yet.

Is it correct to access it like this? unstable_getCustomContext().__hono_context

import type { ExecutionContext } from '@cloudflare/workers-types/experimental';
import { unstable_getCustomContext } from 'waku/server';

const getData = async ({ userId }: { userId: string }) => {
  const { env, executionCtx } = unstable_getCustomContext().__hono_context as {
    env: Env
    executionCtx: ExecutionContext
  };
  executionCtx?.waitUntil(
    new Promise<void>((resolve) => {
      console.log("Waiting for 5 seconds");
      setTimeout(() => {
        console.log("OK, done waiting");
        resolve();
      }, 5000);
    }),
  );
  const { results } = await env.DB.prepare("SELECT * FROM users WHERE user_id = ?")
    .bind(userId)
    .all();
  return results;
}

I think I will close this PR.

Re:
#872 (comment)
#879 (comment)

How could we allow a developer to inject handlers and export Durable Object classes from their worker index file?

The way I have been doing it is to build waku and then copy in a custom index.js file to the dist folder.

We could make that an option to the cloudflare deploy vite plugin - a path to an alternate worker entry file.

Maybe a cloudflare deploy vite plugin option could point to an alternate worker entry file that would be used instead of the default.

Or could there be another way to implement it using getPlatformObject()?

[dai-shi]

Is it correct to access it like this?

Looks good.
I wasn't aware that the db was in the hono context.
https://developers.cloudflare.com/d1/examples/d1-and-hono/

How could we allow a developer to inject handlers and export Durable Object classes from their worker index file?

Oh, I think I misunderstood something.
Please note that I have zero experience with Cloudflare.
Would you create a new discussion and describe the goal briefly?
(It sounds somewhat related to the idea of say adding another Vercel function, which is impossible for now.)

[dai-shi]

@rmarscher see #884