[WIP] pages: Fix "worker called response.clone()" warnings in `wrangler pages dev

[CarmenPopoviciu]

Fixes #3259

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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/7699751320/npm-package-wrangler-4861

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

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/4861/npm-package-wrangler-4861

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/7699751320/npm-package-wrangler-4861 dev path/to/script.js

Additional artifacts:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/7699751320/npm-package-create-cloudflare-4861 --no-auto-update

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/7699751320/npm-package-miniflare-4861

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/7699751320/npm-package-cloudflare-pages-shared-4861

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

---

[email protected] includes the following runtime dependencies:

Package	Constraint	Resolved
miniflare	workspace:*	3.20231218.4
workerd	1.20231218.0	1.20231218.0
workerd --version	1.20231218.0	2023-12-18

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

[Cherry]

Whilst solving one issue, this appears to be a breaking change currently:

<!-- public/index.html -->
<form action="/submit" method="post">
	<input type="text" name="name" placeholder="Jane Doe" />
	<button type="submit">Submit</button>
</form>

// functions/_middleware.ts
export const onRequestPost = async ({ request, next }) => {
	const formData = await request.formData();
	console.log("log", Object.fromEntries(formData.entries()));
	return next();
};

// functions/submit.ts
export const onRequestPost = async ({ request }) => {
	const formData = await request.formData();
	return Response.json(Object.fromEntries(formData.entries()));
};

This code works with the latest version of wrangler, but does not using the pre-release from this PR.

[dario-piotrowicz]

@Cherry thanks a lot, you're totally right, we already internally discussed this.

I think the solution will be to remove the cloning there only when there is a single handler removing this error/warning for just some cases, not ideal but the best solution we can currently implement without introducing a breaking change

Then later in a major bump or whenever possible we should remove the cloning altogether, leaving the responsibility of doing the cloning to the user instead of Pages doing it for them under the hood (so basically your example would break and you'd have to do the cloning of the request yourself to make it work)

What do you think?

[Cherry]

This makes sense to me, thanks @dario-piotrowicz. I totally agree that it should be the responsibility of the developer to clone the Request as needed, but also agree that this needs to be a new major version before landing.

I imagine something like this could work in the short-term: request.bodyUsed ? request.clone() : request (naive and untested).

[dario-piotrowicz]

@Cherry ah yeah thanks a lot for the suggestion!

Somehow your suggestion didn't show up in our discussion 😅, it looks great, I feel like that should work nicely, when I get to this I will look into it and test it out! Thanks a lot! 🙂👍

[petebacondarwin]

I don't think you can clone a request that has already been used. See https://developer.mozilla.org/en-US/docs/Web/API/Request/clone#:~:text=clone()%20throws%20a%20TypeError%20if%20the%20request%20body%20has%20already%20been%20used.%20In%20fact%2C%20the%20main%20reason%20clone()%20exists%20is%20to%20allow%20multiple%20uses%20of%20body%20objects%20(when%20they%20are%20one%2Duse%20only.)

[russelldavis]

Is there anything blocking merging this and bumping the major version? (Using wrangler in a pages project w/ middleware is basically unusable due to all the warnings.)