add IHttpRequestFilter to allow server implementation to filter/reject requests (#753)

* add IHttpRequestFilter to allow server implementation to filter/reject requests

1 files changed, 44 insertions, 2 deletions

diff --git a/src/zenhttp/servers/httpsys.cpp b/src/zenhttp/servers/httpsys.cpp
index 01c4559a1..4df4cd079 100644
--- a/src/zenhttp/servers/httpsys.cpp
+++ b/src/zenhttp/servers/httpsys.cpp
@@ -94,6 +94,7 @@ public:
 	virtual void OnRun(bool TestMode) override;
 	virtual void OnRequestExit() override;
 	virtual void OnRegisterService(HttpService& Service) override;
+	virtual void OnSetHttpRequestFilter(IHttpRequestFilter* RequestFilter) override;
 	virtual void OnClose() override;
 
 	WorkerThreadPool& WorkPool();
@@ -101,6 +102,8 @@ public:
 	inline bool IsOk() const { return m_IsOk; }
 	inline bool IsAsyncResponseEnabled() const { return m_IsAsyncResponseEnabled; }
 
+	IHttpRequestFilter::Result FilterRequest(HttpServerRequest& Request);
+
 private:
 	int	 InitializeServer(int BasePort);
 	void Cleanup();
@@ -137,6 +140,9 @@ private:
 	int32_t					  m_MaxPendingRequests = 128;
 	Event					  m_ShutdownEvent;
 	HttpSysConfig			  m_InitialConfig;
+
+	RwLock							 m_RequestFilterLock;
+	std::atomic<IHttpRequestFilter*> m_HttpRequestFilter = nullptr;
 };
 
 }  // namespace zen
@@ -1672,9 +1678,21 @@ HttpSysTransaction::InvokeRequestHandler(HttpService& Service, IoBuffer Payload)
 	otel::ScopedSpan HttpSpan(SpanNamer, SpanAnnotator);
 #	endif
 
-	if (!HandlePackageOffers(Service, ThisRequest, m_PackageHandler))
+	IHttpRequestFilter::Result FilterResult = m_HttpServer.FilterRequest(ThisRequest);
+	if (FilterResult == IHttpRequestFilter::Result::Accepted)
+	{
+		if (!HandlePackageOffers(Service, ThisRequest, m_PackageHandler))
+		{
+			Service.HandleRequest(ThisRequest);
+		}
+	}
+	else if (FilterResult == IHttpRequestFilter::Result::Forbidden)
 	{
-		Service.HandleRequest(ThisRequest);
+		ThisRequest.WriteResponse(HttpResponseCode::Forbidden);
+	}
+	else
+	{
+		ZEN_ASSERT(FilterResult == IHttpRequestFilter::Result::ResponseSent);
 	}
 
 	return ThisRequest;
@@ -2244,6 +2262,30 @@ HttpSysServer::OnRegisterService(HttpService& Service)
 	RegisterService(Service.BaseUri(), Service);
 }
 
+void
+HttpSysServer::OnSetHttpRequestFilter(IHttpRequestFilter* RequestFilter)
+{
+	RwLock::ExclusiveLockScope _(m_RequestFilterLock);
+	m_HttpRequestFilter.store(RequestFilter);
+}
+
+IHttpRequestFilter::Result
+HttpSysServer::FilterRequest(HttpServerRequest& Request)
+{
+	if (!m_HttpRequestFilter.load())
+	{
+		return IHttpRequestFilter::Result::Accepted;
+	}
+	RwLock::SharedLockScope _(m_RequestFilterLock);
+	IHttpRequestFilter*		RequestFilter = m_HttpRequestFilter.load();
+	if (!RequestFilter)
+	{
+		return IHttpRequestFilter::Result::Accepted;
+	}
+	IHttpRequestFilter::Result FilterResult = RequestFilter->FilterRequest(Request);
+	return FilterResult;
+}
+
 Ref<HttpServer>
 CreateHttpSysServer(HttpSysConfig Config)
 {