Puts TCP sockets behind a compatibility flag.

samples/tcp/config.capnp

@@ -27,6 +27,7 @@ const gopherWorker :Workerd.Worker = (
     (name = "worker", esModule = embed "gopher.js")
   ],
   compatibilityDate = "2022-09-26",
+  compatibilityFlags = ["tcp_sockets_support"],
   # In order to access our configured proxy we need to specify it as a binding. This will allow
   # it to be accessible via `env.proxy` in the JS script.
   bindings = [

src/workerd/api/global-scope.c++

@@ -571,8 +571,9 @@ jsg::Promise<jsg::Ref<Response>> ServiceWorkerGlobalScope::fetch(
 }
 
 jsg::Ref<Socket> ServiceWorkerGlobalScope::connect(
-    jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options) {
-  return connectImpl(js, nullptr, kj::mv(address));
+    jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options,
+    CompatibilityFlags::Reader featureFlags) {
+  return connectImpl(js, nullptr, kj::mv(address), featureFlags);
 }
 
 }  // namespace workerd::api

src/workerd/api/global-scope.h

@@ -274,7 +274,8 @@ class ServiceWorkerGlobalScope: public WorkerGlobalScope {
       CompatibilityFlags::Reader featureFlags);
 
   jsg::Ref<Socket> connect(
-      jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options);
+      jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options,
+      CompatibilityFlags::Reader featureFlags);
 
   jsg::Ref<ServiceWorkerGlobalScope> getSelf() {
     return JSG_THIS;

src/workerd/api/http.c++

@@ -1808,8 +1808,9 @@ jsg::Promise<jsg::Ref<Response>> fetchImpl(
 }
 
 jsg::Ref<Socket> Fetcher::connect(
-    jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options) {
-  return connectImpl(js, JSG_THIS, kj::mv(address));
+    jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options,
+    CompatibilityFlags::Reader featureFlags) {
+  return connectImpl(js, JSG_THIS, kj::mv(address), featureFlags);
 }
 
 jsg::Promise<jsg::Ref<Response>> Fetcher::fetch(

src/workerd/api/http.h

@@ -406,7 +406,8 @@ class Fetcher: public jsg::Object {
   // specified on URLs, Fetcher-specific URL decoding options, and error handling.
 
   jsg::Ref<Socket> connect(
-      jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options);
+      jsg::Lock& js, kj::String address, jsg::Optional<SocketOptions> options,
+      CompatibilityFlags::Reader featureFlags);
 
   jsg::Promise<jsg::Ref<Response>> fetch(
       jsg::Lock& js, kj::OneOf<jsg::Ref<Request>, kj::String> requestOrUrl,

src/workerd/api/sockets.c++

@@ -78,7 +78,11 @@ jsg::Ref<Socket> connectImplNoOutputLock(
 }
 
 jsg::Ref<Socket> connectImpl(
-    jsg::Lock& js, kj::Maybe<jsg::Ref<Fetcher>> fetcher, kj::String address) {
+    jsg::Lock& js, kj::Maybe<jsg::Ref<Fetcher>> fetcher, kj::String address,
+    CompatibilityFlags::Reader featureFlags) {
+  if (!featureFlags.getTcpSocketsSupport()) {
+    JSG_FAIL_REQUIRE(TypeError, "TCP Sockets API not enabled.");
+  }
   jsg::Ref<Fetcher> actualFetcher = nullptr;
   KJ_IF_MAYBE(f, fetcher) {
     actualFetcher = kj::mv(*f);

src/workerd/api/sockets.h

@@ -114,7 +114,8 @@ jsg::Ref<Socket> connectImplNoOutputLock(
     jsg::Lock& js, jsg::Ref<Fetcher> fetcher, kj::String address);
 
 jsg::Ref<Socket> connectImpl(
-    jsg::Lock& js, kj::Maybe<jsg::Ref<Fetcher>> fetcher, kj::String address);
+    jsg::Lock& js, kj::Maybe<jsg::Ref<Fetcher>> fetcher, kj::String address,
+    CompatibilityFlags::Reader featureFlags);
 
 #define EW_SOCKETS_ISOLATE_TYPES         \
   api::Socket,                       \

src/workerd/io/compatibility-date.capnp

@@ -227,9 +227,15 @@ struct CompatibilityFlags @0x8f8c1b68151b6cef {
   # request that no compression be used.
 
   nodeJs18CompatExperimental @21 :Bool
-        $compatEnableFlag("nodejs_18_compat_experimental");
+      $compatEnableFlag("nodejs_18_compat_experimental");
   # Experimental, do not use.
   # Enables nodejs 18 compat imports in the application.
   # This is currently a work in progress mechanism that is not yet available for use in workerd.
   # WARNING: IT WILL BREAK in the future. Do not ignore this warning.
+
+  tcpSocketsSupport @22 :Bool
+      $compatEnableFlag("tcp_sockets_support");
+  # Enables TCP sockets in workerd.
+  # These are still under development and therefore subject to change.
+  # WARNING: DO NOT depend on this feature as its API is still subject to change.
 }