Add basic support for wrappedBindings and RPC entrypoints to Miniflare's Magic Proxy

[penalosa]

What this PR solves / how to test

This fixes a number of issues with the Miniflare magic proxy, including:

• Fixes 🐛 BUG: getPlatformProxy doesn't provide an AI binding when it should #5575
• Fixes 🐛 BUG: Miniflare's getBindings does not properly expose RPC entrypoints #5577 (partial support, not including stubs or calling returned functions)

Author has addressed the following

• Tests
  • TODO (before merge)
  • Included
  • Not necessary because:
• Changeset (Changeset guidelines)
  • TODO (before merge)
  • Included
  • Not necessary because:
• Public documentation
  • TODO (before merge)
  • Cloudflare docs PR(s): https://github.com/cloudflare/cloudflare-docs/pull/...
  • Not necessary because: bugfixes

[changeset-bot]

🦋 Changeset detected

Latest commit: 8fdc2b0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
miniflare	Patch
@cloudflare/pages-shared	Patch
@cloudflare/vitest-pool-workers	Patch
wrangler	Patch

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[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-wrangler-5599

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/5599/npm-package-wrangler-5599

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-wrangler-5599 dev path/to/script.js

Additional artifacts:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-create-cloudflare-5599 --no-auto-update

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-cloudflare-kv-asset-handler-5599

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-miniflare-5599

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-cloudflare-pages-shared-5599

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/8692725908/npm-package-cloudflare-vitest-pool-workers-5599

Note that these links will no longer work once the GitHub Actions artifact expires.

---

wrangler@3.50.0 includes the following runtime dependencies:

Package	Constraint	Resolved
miniflare	workspace:*	3.20240405.1
workerd	1.20240405.0	1.20240405.0
workerd --version	1.20240405.0	2024-04-05

Please ensure constraints are pinned, and miniflare/workerd minor versions match.

[dario-piotrowicz]

With the correct env variables the wrangler AI e2e passes locally:

on Github I think we need to make sure that the CLOUDFLARE_API_TOKEN grants access to Workers AI (I've tested with this with my own Cloudflare account id and api token) (to fix this error. Regarding the python e2e failures I am not sure what they are about, I don't think they are related to this PR as I can see those failing elsewhere too)

I don't think I have permissions to do the above, maybe someone could help me? 🙂 @petebacondarwin? 🙏

[dario-piotrowicz]

Note

The wrappedBindings support is not perfect, it seems to break in some cases: https://github.com/dario-piotrowicz/miniflare-wrappedBindings-getBindings-function-stringification-error-repro
but it is good enough for the AI binding, so if it'd be acceptable I'd like to proceed with the current solution
(to enable AI binding proxies as soon as we can) and address the above issue as a follow up

I think I've already got a solution for this: 01fa456 but I'd prefer not to scope creep this PR and try to lend it asap instead of piling stuff on top of it