feat(examples): add Prisma + Hyperdrive example

[JamesbbBriz]

Summary

Add a full-stack CRUD example demonstrating Prisma v7 with Hyperdrive on Cloudflare Workers. This is the first database example in the repo — fills a major gap for users migrating data-driven apps to vinext.

What it shows

• Per-request PrismaClient: avoids the alternating connection failure pattern on Workers (Alternating request failures (success, fail, success...) when using Drizzle + Postgres lazily evaluated in vinext / Cloudflare Workers #537)
• Hyperdrive: connection pooling via cloudflare:workers binding
• Server component: data fetching with Prisma in a React Server Component
• Route handler: CRUD API using standard Web Request/Response (not NextRequest)

Structure

examples/prisma-hyperdrive/
├── app/
│   ├── layout.tsx              # Root layout
│   ├── page.tsx                # Server component: list items from DB
│   └── api/items/route.ts      # GET + POST route handler
├── lib/db.ts                   # Per-request Prisma client (50ms TTL pattern)
├── prisma/schema.prisma        # Simple Item model
├── vite.config.ts              # Standard vinext + cloudflare config
├── wrangler.jsonc              # Hyperdrive binding
└── worker/index.ts             # Uses virtual:vinext-app-handler

Key pattern: per-request client

let cached: PrismaClient | null = null;
let cachedAt = 0;

export function getPrisma(): PrismaClient {
  const now = Date.now();
  if (cached && now - cachedAt < 50) return cached;
  const pool = new Pool({ connectionString: env.HYPERDRIVE.connectionString });
  cached = new PrismaClient({ adapter: new PrismaPg(pool) });
  cachedAt = now;
  return cached;
}

This pattern is production-validated — we run it on Workers Free plan (10ms CPU limit) with zero alternating failures.

Blast radius

Zero — new directory only, no changes to existing code.

Relates to #537

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Import the supported vinext app entry

virtual:vinext-app-handler is not a virtual module that vinext resolves, so this export will fail during bundling with an unresolved import and the example cannot build/deploy. In packages/vinext/src/index.ts, the resolver only handles IDs like virtual:vinext-rsc-entry, virtual:vinext-app-ssr-entry, and virtual:vinext-app-browser-entry (or the non-virtual vinext/server/app-router-entry).

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Stop reusing Prisma client across requests

This time-based cache is not actually request-scoped: two different requests that arrive within 50ms (including concurrent requests in one Worker isolate) will receive the same PrismaClient. Since this example’s rationale is avoiding cross-request connection reuse, this condition can reintroduce the same class of failures under load and makes behavior nondeterministic by request timing.

Useful? React with 👍 / 👎.