Added etag feature

src/projects/config/items/modules/etag.h

@@ -0,0 +1,33 @@
+//==============================================================================
+//
+//  OvenMediaEngine
+//
+//  Created by Getroot
+//  Copyright (c) 2022 AirenSoft. All rights reserved.
+//
+//==============================================================================
+#pragma once
+
+#include "module_template.h"
+
+namespace cfg
+{
+	namespace modules
+	{
+		struct ETag : public ModuleTemplate
+		{
+		protected:
+
+		public:
+
+		protected:
+			void MakeList() override
+			{
+				// Experimental feature is disabled by default
+				SetEnable(false);
+
+				ModuleTemplate::MakeList();
+			}
+		};
+	} // namespace modules
+} // namespace cfg

src/projects/config/items/modules/modules.h

@@ -13,6 +13,7 @@
 #include "p2p.h"
 #include "recovery.h"
 #include "dynamic_app_removal.h"
+#include "etag.h"
 
 namespace cfg
 {
@@ -26,13 +27,15 @@ namespace cfg
 			P2P _p2p;
 			Recovery _recovery;
 			DynamicAppRemoval _dynamic_app_removal;
+			ETag _etag;
 
 		public:
 			CFG_DECLARE_CONST_REF_GETTER_OF(GetHttp2, _http2)
 			CFG_DECLARE_CONST_REF_GETTER_OF(GetLLHls, _ll_hls)
 			CFG_DECLARE_CONST_REF_GETTER_OF(GetP2P, _p2p)
 			CFG_DECLARE_CONST_REF_GETTER_OF(GetRecovery, _recovery)
 			CFG_DECLARE_CONST_REF_GETTER_OF(GetDynamicAppRemoval, _dynamic_app_removal)
+			CFG_DECLARE_CONST_REF_GETTER_OF(GetETag, _etag)
 
 		protected:
 			void MakeList() override
@@ -42,6 +45,7 @@ namespace cfg
 				Register<Optional>({"P2P", "p2p"}, &_p2p);
 				Register<Optional>("Recovery", &_recovery);
 				Register<Optional>("DynamicAppRemoval", &_dynamic_app_removal);
+				Register<Optional>("ETag", &_etag);
 			}
 		};
 	}  // namespace modules

src/projects/modules/http/server/http1/http1_response.cpp

@@ -60,7 +60,9 @@ namespace http
 				std::shared_ptr<ov::Data> response = std::make_shared<ov::Data>(65535);
 				ov::ByteStream stream(response.get());
 
-				if (_chunked_transfer == false)
+				if (_chunked_transfer == false && 
+						GetStatusCode() != StatusCode::NoContent && 
+						GetStatusCode() != StatusCode::NotModified)
 				{
 					// Calculate the content length
 					SetHeader("Content-Length", ov::Converter::ToString(GetResponseDataSize()));

src/projects/modules/http/server/http_exchange.cpp

@@ -37,7 +37,9 @@ namespace http
 		void HttpExchange::Release()
 		{
 			// print debug info
-			if ((static_cast<int>(GetResponse()->GetStatusCode()) / 100) != 2)
+			// 200 / 300 are not error
+			if ((static_cast<int>(GetResponse()->GetStatusCode()) / 100) != 2 &&
+				(static_cast<int>(GetResponse()->GetStatusCode()) / 100) != 3)
 			{
 				logte("\n%s", GetDebugInfo().CStr());
 			}
@@ -271,7 +273,16 @@ namespace http
 				return InterceptorResult::Error;
 			}
 
-			GetResponse()->SetMethod(GetRequest()->GetMethod());
+			auto request = GetRequest();
+			auto response = GetResponse();
+
+			response->SetMethod(request->GetMethod());
+
+			auto if_none_match = request->GetHeader("If-None-Match");
+			if (if_none_match.IsEmpty() == false)
+			{
+				response->SetIfNoneMatch(if_none_match);
+			}
 
 			return interceptor->OnRequestCompleted(GetSharedPtr());
 		}

src/projects/modules/http/server/http_response.cpp

@@ -13,6 +13,7 @@
 #include <algorithm>
 #include <memory>
 #include <utility>
+#include "config/config_manager.h"
 
 #include "./http_server_private.h"
 
@@ -26,6 +27,9 @@ namespace http
 			OV_ASSERT2(_client_socket != nullptr);
 
 			_created_time = std::chrono::system_clock::now();
+
+			auto module_config = cfg::ConfigManager::GetInstance()->GetServer()->GetModules();
+			_etag_enabled_by_config = module_config.GetETag().IsEnabled();
 		}
 
 		HttpResponse::HttpResponse(const std::shared_ptr<HttpResponse> &http_response)
@@ -74,6 +78,16 @@ namespace http
 			return _method;
 		}
 
+		void HttpResponse::SetIfNoneMatch(const ov::String &etag)
+		{
+			_if_none_match = etag;
+		}
+
+		const ov::String &HttpResponse::GetIfNoneMatch() const
+		{
+			return _if_none_match;
+		}
+
 		StatusCode HttpResponse::GetStatusCode() const
 		{
 			return _status_code;
@@ -156,6 +170,16 @@ namespace http
 			return true;
 		}
 
+		ov::String HttpResponse::GetEtag()
+		{
+			if (_response_hash == nullptr)
+			{
+				return "";
+			}
+
+			return ov::String::FormatString("%s-%d", _response_hash->ToHexString().CStr(), _response_data_size);
+		}
+
 		bool HttpResponse::AppendData(const std::shared_ptr<const ov::Data> &data)
 		{
 			if (data == nullptr)
@@ -170,6 +194,33 @@ namespace http
 			_response_data_list.push_back(cloned_data);
 			_response_data_size += cloned_data->GetLength();
 
+			if (_etag_enabled_by_config == false)
+			{
+				return true;
+			}
+
+			auto md5 = ov::MessageDigest::ComputeDigest(ov::CryptoAlgorithm::Md5, cloned_data);
+			if (md5 == nullptr || md5->GetLength() != 16)
+			{
+				// Could not compute MD5
+				OV_ASSERT2(md5->GetLength() == 16);
+				return true;
+			}
+
+			if (_response_hash == nullptr)
+			{
+				_response_hash = md5;
+			}
+			else
+			{
+				// Update hash, xor with previous hash
+				for (size_t i = 0; i < md5->GetLength(); i++)
+				{
+					auto ptr = _response_hash->GetWritableDataAs<uint8_t>();
+					ptr[i] ^= md5->At(i);
+				}
+			}
+
 			return true;
 		}
 
@@ -237,9 +288,33 @@ namespace http
 			_response_time = std::chrono::system_clock::now();
 
 			uint32_t sent_size = 0;
+			bool only_header = false;
 
 			if (IsHeaderSent() == false)
 			{
+				if (_etag_enabled_by_config == true)
+				{
+					// IF-NONE-MATCH check
+					auto if_none_match = GetIfNoneMatch();
+					if (if_none_match.IsEmpty() == false)
+					{
+						if (if_none_match == GetEtag())
+						{
+							SetStatusCode(StatusCode::NotModified);
+							only_header = true;
+						}
+					}
+
+					if (GetStatusCode() == StatusCode::OK || GetStatusCode() == StatusCode::NotModified)
+					{
+						auto etag_value = GetEtag();
+						if (etag_value.IsEmpty() == false)
+						{
+							SetHeader("ETag", etag_value);
+						}
+					}
+				}
+
 				auto sent_header_size = SendHeader();
 				// Header must be bigger than 0, if header is not sent, it is an error
 				if (sent_header_size <= 0)
@@ -254,7 +329,7 @@ namespace http
 				}
 			}
 
-			if (GetMethod() == Method::Head)
+			if (GetMethod() == Method::Head || only_header == true)
 			{
 				_sent_size += sent_size;
 				return sent_size;

src/projects/modules/http/server/http_response.h

@@ -37,6 +37,9 @@ namespace http
 			void SetMethod(Method method);
 			Method GetMethod() const;
 
+			void SetIfNoneMatch(const ov::String &etag);
+			const ov::String &GetIfNoneMatch() const;
+
 			// reason = default
 			void SetStatusCode(StatusCode status_code);
 			// custom reason
@@ -92,6 +95,8 @@ namespace http
 			virtual int32_t SendHeader();
 			virtual int32_t SendPayload();
 
+			ov::String GetEtag();
+
 			std::shared_ptr<ov::ClientSocket> _client_socket;
 			std::shared_ptr<ov::TlsServerData> _tls_data;
 
@@ -128,6 +133,10 @@ namespace http
 			uint32_t _sent_size = 0;
 
 			Method _method = Method::Unknown;
+
+			bool _etag_enabled_by_config = false;
+			ov::String _if_none_match = "";
+			std::shared_ptr<ov::Data> _response_hash = nullptr;
 		};
 	}  // namespace svr
 }  // namespace http