Add environment to Cloudflare adapter

[piperswe]

Describe the problem

Cloudflare Workers provide an environment object containing environment variables and bindings to other Cloudflare services, such as Workers KV and Durable Objects. Currently, the Cloudflare adapter doesn't seem pass this object to endpoints, so those endpoints can't access those services.

Describe the proposed solution

The Cloudflare adapter should pass the environment object through to the endpoint somehow, potentially through the request's locals. In addition, it would be great to have a way to export Durable Object classes.

Alternatives considered

No response

Importance

would make my life easier

Additional Information

No response

[piperswe]

Related to #2807

[tv42]

Not being able to access Cloudflare KV makes implementing sessions way too hard :-(

[samuba]

@tv42 yeah it is a pity. For now I'm using KV via API in my project. It works but is cumbersome.

[denizkenan]

I had to fork existing adapter and pass env to request object. It is a pity that this adapter even exists(it is pre-alpha IMHO). Without providing access to ENV & Durable Objects, using workers is almost pointless.

[eric-naguras]

We need this, I hope it will be fixed soon.

[bryanwood]

I had to fork existing adapter and pass env to request object. It is a pity that this adapter even exists(it is pre-alpha IMHO). Without providing access to ENV & Durable Objects, using workers is almost pointless.

This no longer works since the commit that added a check for the keys being passed in from the adapter:

kit/packages/kit/src/core/build/build_server.js

Lines 91 to 94 in f89fb52

	// TODO remove this for 1.0
	if (Object.keys(request).sort().join() !== 'headers,method,rawBody,url') {
	throw new Error('Adapters should call app.render({ url, method, headers, rawBody })');
	}

As a workaround I'm adding env as a property/symbol so it'll be available as in hooks.js.

In the forked adapter:

 const rendered = await app.render({
        url,
        rawBody: new Uint8Array(await req.arrayBuffer()),
        headers: Object.fromEntries(req.headers),
        method: req.method,
        [Symbol.for("cf-env")]: env,
      });

I imagine passing extra keys on the request object would begin working again once that TODO to remove the check is resolved.

Not sure if passing extra properties to the request object is going to be a reliable way of passing platform features along to hooks.js and endpoints, guessing it's not specifically part of the app.render api contract?

Edit: Changed to passing env via symbol property so it doesn't appear in Object.keys().

[benmccann]

This should be implemented now

https://github.com/sveltejs/kit/tree/master/packages/adapter-cloudflare#environment-variables