fix(vite-plugin): preserve worker websocket service bindings in dev

[raashish1601]

Fixes #13054.

WebSocket upgrade requests for dev-mode worker service bindings currently get routed through __VITE_MIDDLEWARE__, which only has the Node middleware bridge. That makes proxied worker-to-worker WebSocket upgrades miss the real entry worker and crash in Miniflare's loopback upgrade path.

This change routes Upgrade: websocket requests in __vite_proxy_worker__ straight to ENTRY_USER_WORKER.fetch(...) while keeping normal HTTP requests on the existing Vite middleware path. I also added a focused unit test for the proxy dispatch logic and a multi-worker playground regression covering Worker A -> Worker B WebSocket proxying in dev mode.

Local validation:

• node node_modules/vitest/vitest.mjs run src/__tests__/vite-proxy-worker.spec.ts
• node node_modules/tsdown/dist/run.mjs
• node node_modules/typescript/bin/tsc -b packages/vite-plugin-cloudflare/playground/multi-worker/tsconfig.json
• I attempted to run the targeted playground e2e spec as well, but this Windows host does not currently have the required Playwright Chromium binary installed.

---

• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: this is an internal Vite dev-mode service-binding fix with no public API or docs surface.

A picture of a cute animal (not mandatory, but encouraged)

---

[changeset-bot]

🦋 Changeset detected

Latest commit: 4842265

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[workers-devprod]

Codeowners approval required for this PR:

• @cloudflare/wrangler

Show detailed file reviewers

• packages/vite-plugin-cloudflare/src/workers/vite-proxy-worker/index.ts: [@cloudflare/wrangler]

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 3 additional findings.

[pkg-pr-new]

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@13098

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@13098

miniflare

npm i https://pkg.pr.new/miniflare@13098

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@13098

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@13098

@cloudflare/vite-plugin

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@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@13098

@cloudflare/workers-editor-shared

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wrangler

npm i https://pkg.pr.new/wrangler@13098

commit: 4842265

[jamesopstad]

Hi @raashish1601. Thanks for the PR and for fixing the issue! There are just some formatting issues so please can you run pnpm prettify from the root of the repo and then push up the changes. Then we can get it merged.

[Jdruwe]

Just wondering if this PR will solve my usecase:

• Turboreporo
• 2 apps
  -- /apps/chat-agent
  -- /apps/web

web wrangler file:

...
  "services": [
    {
      "binding": "ChatAgent",
      "service": "chat-agent",
      "entrypoint": "ChatAgent"
    }
  ]

Running locally using turbo dev I am getting in my web app:

SyntaxError: Unexpected token '', ""... is not valid JSON
    at JSON.parse (<anonymous>)
    at parseJSONFromBytes

I have a feeling this is also related to the web app not being able to properly resolve the chat-agent in time?

[apostolos-geyer]

any timeline on this getting shipped?