Copy of #7575

[fhanau]

No description provided.

[ask-bonk]

Since last review: 0 resolved, 1 still open, 2 new.

Introduces a wrapped TypeScript Hyperdrive binding and virtual-host routing for PostgreSQL and MySQL.

Findings outside the diff

• [BLOCKING] src/workerd/api/http.c++:2345-2352: This stored callback captures JSG_THIS in a kj::Function, and the global scope never visits connectOverrides. The jsg::Ref<Fetcher> is consequently untraced while held by the isolate-global map, which can leave a stale GC-managed reference. Make ConnectFn a jsg::Function, make this lambda visitable, and visit each map value from ServiceWorkerGlobalScope::visitForGc().

  using ConnectFn = jsg::Function<jsg::Ref<api::Socket>()>;
  
  void visitForGc(jsg::GcVisitor& visitor) {
    visitor.visit(processValue, bufferValue, defaultFetcher);
    for (auto& entry: connectOverrides) {
      visitor.visit(entry.value);
    }
  }
  
  JSG_VISITABLE_LAMBDA((self = JSG_THIS), (self), (jsg::Lock& js) mutable {
    return self->connect(
        js,
        kj::str(KJ_ASSERT_NONNULL(self->host), ":", KJ_ASSERT_NONNULL(self->port)),
        kj::none);
  })
  

Carried forward from the last review: api-compat, jsg-gc (no author changes in their files since then; earlier findings stand)

Not re-run: tests, docs, compat-flags, design-simplicity, kj-style, memory-safety (no author changes in their files since the last review)

---

_{Reviewed commit: 65187428 · github run}

[ask-bonk]

[BLOCKING] mapVirtualHost() registers only a connectOverrides entry. Although the generated .workers.alt hostname is recognized by node:dns, getCallerDnsOverride() has no corresponding DNS entry and lookup falls through to normal DNS. The binding also does not define ip, despite the public Hyperdrive interface requiring a synthetic IPv4 for drivers that need an IP literal. Consequently, drivers that resolve connectionString's host, or read hd.ip, cannot connect through this binding. Register a synthetic IPv4 as both a DNS and connect override and expose it as the binding's ip property; cover dns.lookup(hd.host) and connect(${hd.ip}:${hd.port}) in this test suite.

[ask-bonk]

[WARNING] The binding's constructor is reachable as Object.getPrototypeOf(env.HYPERDRIVE).constructor. A Worker with a Durable Object namespace can repeatedly construct wrappers around fresh getByName() stubs. Each constructor call creates a random host and permanently inserts a new entry into the isolate-global connectOverrides map; the map has no removal path. This permits untrusted code to accumulate native entries across requests until the isolate runs out of memory. Require a module-private construction token and create instances only through the two binding factories.

Suggested change

	const authority = entrypoints.mapVirtualHost(this.#fetcher, this.#port);
	const hyperdriveBindingToken = Symbol();
	constructor(token: symbol, env: HyperdriveEnv, scheme: HyperdriveScheme) {
	if (token !== hyperdriveBindingToken) {
	throw new TypeError('Hyperdrive bindings cannot be constructed directly');
	}
	super(env.fetcher);
	// ...
	}
	export function makeHyperdrive(env: HyperdriveEnv, scheme: HyperdriveScheme): Hyperdrive {
	return new Hyperdrive(hyperdriveBindingToken, env, scheme);
	}