From 103f6ff03c250f38f30322ea81c2d66739d6f10a Mon Sep 17 00:00:00 2001
From: Dries De Winter <32574669+driesdewinter@users.noreply.github.com>
Date: Tue, 16 Jan 2024 20:38:26 +0100
Subject: [PATCH] Add binding for App.filter (#1010)

---
 docs/index.d.ts  |  2 ++
 src/AppWrapper.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/docs/index.d.ts b/docs/index.d.ts
index 496316ed..6b3c4fe8 100644
--- a/docs/index.d.ts
+++ b/docs/index.d.ts
@@ -325,6 +325,8 @@ export interface TemplatedApp {
     removeServerName(hostname: string) : TemplatedApp;
     /** Registers a synchronous callback on missing server names. See /examples/ServerName.js. */
     missingServerName(cb: (hostname: string) => void) : TemplatedApp;
+    /** Attaches a "filter" function to track socket connections / disconnections */
+    filter(cb: (res: HttpResponse, count: Number) => void | Promise<void>) : TemplatedApp;
     /** Closes all sockets including listen sockets. This will forcefully terminate all connections. */
     close() : TemplatedApp;
 }
diff --git a/src/AppWrapper.h b/src/AppWrapper.h
index 1a05ce02..96d4447a 100644
--- a/src/AppWrapper.h
+++ b/src/AppWrapper.h
@@ -431,6 +431,34 @@ void uWS_App_listen(const FunctionCallbackInfo<Value> &args) {
     args.GetReturnValue().Set(args.Holder());
 }
 
+template <typename APP>
+void uWS_App_filter(const FunctionCallbackInfo<Value> &args) {
+    APP *app = (APP *) args.Holder()->GetAlignedPointerFromInternalField(0);
+
+    /* Handler */
+    Callback checkedCallback(args.GetIsolate(), args[0]);
+    if (checkedCallback.isInvalid(args)) {
+        return;
+    }
+    UniquePersistent<Function> cb = checkedCallback.getFunction();
+
+    /* This function requires perContextData */
+    PerContextData *perContextData = (PerContextData *) Local<External>::Cast(args.Data())->Value();
+
+    app->filter([cb = std::move(cb), perContextData](auto *res, int count) {
+        Isolate *isolate = perContextData->isolate;
+        HandleScope hs(isolate);
+
+        Local<Object> resObject = perContextData->resTemplate[getAppTypeIndex<APP>()].Get(isolate)->Clone();
+        resObject->SetAlignedPointerInInternalField(0, res);
+
+        Local<Value> argv[] = {resObject, Local<Value>::Cast(Integer::New(isolate, count))};
+        CallJS(isolate, cb.Get(isolate), 2, argv);
+    });
+
+    args.GetReturnValue().Set(args.Holder());
+}
+
 template <typename APP>
 void uWS_App_domain(const FunctionCallbackInfo<Value> &args) {
     APP *app = (APP *) args.Holder()->GetAlignedPointerFromInternalField(0);
@@ -719,6 +747,7 @@ void uWS_App(const FunctionCallbackInfo<Value> &args) {
 
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "close", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_close<APP>, args.Data()));
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "listen_unix", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_listen_unix<APP>, args.Data()));
+        appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "filter", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_filter<APP>, args.Data()));
 
         /* ws, listen */
         appTemplate->PrototypeTemplate()->Set(String::NewFromUtf8(isolate, "ws", NewStringType::kNormal).ToLocalChecked(), FunctionTemplate::New(isolate, uWS_App_ws<APP>, args.Data()));