Use epoll facilities

readme.md

@@ -2,6 +2,9 @@
 
 http-server is a simple http server that does not conform to any standards. It's main purpose is for experimentation: both playing around with HTTP quirks and simple socket programming under Linux.
 
+## Versions
+The current master branch version is epoll based, but a traditional iterative version was tagged as `traditional-iterative` (use `git show traditional-iterative` to view more information about it).
+
 ## Requirements
 I have tested building the program with the following compilers:
 - gcc 8.3.0

src/server/connectionoperator.cpp

@@ -6,22 +6,9 @@
 #include <cstdio>
 #include <sstream>
 
-void ConnectionOperator::SendResponse(ClientSocket const & clientSocket, Http::Response const & response) const
+std::vector<char> ConnectionOperator::HandleNewConnection(int fd)
 {
-	auto bytesToSend = response.Serialize();
-	try
-	{
-		clientSocket.WriteBytes(bytesToSend);
-	}
-	catch(std::runtime_error & e)
-	{
-		logger.Error("Error writing data to clientSocket");
-	}
-}
-
-void ConnectionOperator::HandleNewConnection(ClientSocket const & newClient)
-{
-	auto requestBytes = newClient.ReadBytes();
+	auto requestBytes = Socket::ReadBytes(fd, 512);
 	Http::Request request;
 	Http::Response response;
 	try
@@ -37,8 +24,8 @@ void ConnectionOperator::HandleNewConnection(ClientSocket const & newClient)
 		logger.Error(ss.str());
 
 		response.code = HttpResponse::Code::BAD_REQUEST;
-		SendResponse(newClient, response);
-		return;
+
+		return response.Serialize();
 	}
 
 	for(size_t i = 0; i < middlewares.size(); ++i)
@@ -57,12 +44,11 @@ void ConnectionOperator::HandleNewConnection(ClientSocket const & newClient)
 		logger.Error(ss.str());
 
 		response.code = HttpResponse::Code::NOT_IMPLEMENTED;
-		SendResponse(newClient, response);
-		return;
+		
+		return response.Serialize();
 	}
 
-	auto bytesToSend = response.Serialize();
-	newClient.WriteBytes(bytesToSend);
+	return response.Serialize();
 }
 
 ConnectionOperator::ConnectionOperator(Logger & _logger, ServerConfiguration const & serverConfiguration)

src/server/connectionoperator.hpp

@@ -2,7 +2,7 @@
 #include "../logger.hpp"
 #include "../middleware/base.hpp"
 #include <memory>
-#include "socket/clientsocket.hpp"
+#include "socket.hpp"
 #include <string>
 #include <vector>
 
@@ -12,10 +12,8 @@ private:
 	Logger & logger;
 	std::vector<std::unique_ptr<Middleware::BaseMiddleware>> middlewares;
 
-	void SendResponse(ClientSocket const & clientSocket, Http::Response const & response) const;
-
 public:
-	void HandleNewConnection(ClientSocket const & newClient);
+	std::vector<char> HandleNewConnection(int fd);
 
 	ConnectionOperator(Logger & logger, ServerConfiguration const & serverConfiguration);
 };

src/server/server.cpp

@@ -1,32 +1,119 @@
 #include "../logger.hpp"
 #include "configuration.hpp"
 #include "server.hpp"
+#include <set>
 #include <sstream>
 #include <stdexcept>
+#include <sys/epoll.h>
+#include <unistd.h>
+
+void HttpServer::HandleEpollInEvent(int fd)
+{
+	if (fd != listeningSocketFileDescriptor)
+	{
+		logger.Info("EPOLLIN Attempted to handle a non registered file descriptor");
+
+		return;
+	}
+
+	unsigned sockaddrSize = sizeof(sockaddr_in);
+	int const connectionFileDescriptor = accept(
+		listeningSocketFileDescriptor,
+		reinterpret_cast<sockaddr *>(&socketAddress),
+		&sockaddrSize);
+	
+	socketWriteMap[connectionFileDescriptor] = connectionOperator.HandleNewConnection(connectionFileDescriptor);
+
+	epoll_event event;
+	event.data.fd = connectionFileDescriptor;
+	event.events = EPOLLOUT | EPOLLONESHOT;
+	if (epoll_ctl(pollFileDescriptor, EPOLL_CTL_ADD, connectionFileDescriptor, &event) < 0)
+	{
+		logger.Error("Error registering file descriptor for EPOLLOUT");
+	}
+}
+
+void HttpServer::HandleEpollOutEvent(int fd)
+{
+	auto result = socketWriteMap.find(fd);
+	if (result == socketWriteMap.end())
+	{
+		logger.Error("EPOLLOUT Event for unexpected fd");
+		return;
+	}
+
+	Socket::WriteBytes(fd, result->second);
+	close(fd);
+}
 
 void HttpServer::Execute()
 {
+	std::vector<epoll_event> epollEvents;
+	epollEvents.resize(1000);
+
 	while(isOpen)
 	{
-		try
+		int eventsHappened = epoll_wait(pollFileDescriptor, epollEvents.data(), static_cast<int>(epollEvents.size()), -1);
+		for (int i = 0; i < eventsHappened; ++i)
 		{
-			ClientSocket newClient = listeningSocket.AcceptNextConnection();
-			connectionOperator.HandleNewConnection(newClient);
-		}
-		catch (std::runtime_error & e)
-		{
-			logger.Info("ClientSocket dropped on accept");
+			int const fd = epollEvents[i].data.fd;
+			if (epollEvents[i].events & EPOLLIN)
+			{
+				HandleEpollInEvent(fd);
+			}
+			else
+			{
+				HandleEpollOutEvent(fd);
+			}
 		}
 	}
 }
 	
 HttpServer::HttpServer(Logger & _logger, ServerConfiguration const & serverConfiguration)
 	: logger(_logger),
-	listeningSocket(serverConfiguration.GetPort()),
+	pollFileDescriptor(-1),
+	listeningSocketFileDescriptor(-1),
 	connectionOperator(_logger, serverConfiguration),
 	isOpen(true)
 {
+	pollFileDescriptor = epoll_create1(0);
+	if (pollFileDescriptor < 0)
+	{
+		throw std::runtime_error("Error creating epoll file descriptor");
+	}
+
+	socketAddress.sin_family = AF_INET;
+	socketAddress.sin_addr.s_addr = INADDR_ANY;
+	socketAddress.sin_port = htons(serverConfiguration.GetPort());
+
+	listeningSocketFileDescriptor = ListeningSocket::Create(socketAddress, 10000);
+	if (listeningSocketFileDescriptor < 0)
+	{
+		throw std::runtime_error("Error creating listening socket");
+	}
+
+	epoll_event event;
+	event.data.fd = listeningSocketFileDescriptor;
+	event.events = EPOLLIN;
+	if (epoll_ctl(pollFileDescriptor, EPOLL_CTL_ADD, listeningSocketFileDescriptor, &event) < 0)
+	{
+		throw std::runtime_error("Error registering listening socket with epoll facilities");
+	}
+
 	std::stringstream ss;
 	ss << "Listening on port " << serverConfiguration.GetPort();
 	logger.Info(ss.str());
+}
+
+HttpServer::~HttpServer()
+{
+	if (listeningSocketFileDescriptor >= 0)
+	{
+		close(listeningSocketFileDescriptor);
+	}
+
+	if (pollFileDescriptor >= 0)
+	{
+		close(pollFileDescriptor);
+	}
 }

src/server/server.hpp

@@ -1,20 +1,28 @@
 #pragma once
 #include "../logger.hpp"
 #include "connectionoperator.hpp"
-#include "socket/listeningsocket.hpp"
+#include <map>
 
 class HttpServer
 {
 private:
 	Logger & logger;
-	ListeningSocket listeningSocket;
+	int pollFileDescriptor;
+	sockaddr_in socketAddress;
+	int listeningSocketFileDescriptor;
+	std::map<int, std::vector<char>> socketWriteMap;
 	ConnectionOperator connectionOperator;
 	bool isOpen;
 
+	void HandleEpollInEvent(int fd);
+
+	void HandleEpollOutEvent(int fd);
+
 public:
 	void Execute();
 	
 	HttpServer(Logger & logger, ServerConfiguration const & serverConfiguration);
+	~HttpServer();
 	HttpServer(HttpServer & other) = delete;
 	HttpServer & operator=(HttpServer & other) = delete;
 };

src/server/socket.cpp

@@ -0,0 +1,85 @@
+#include "socket.hpp"
+#include <stdexcept>
+#include <unistd.h>
+
+namespace ListeningSocket
+{
+	int Create(sockaddr_in & socketAddress, int const connectionLimit)
+	{
+		int socketFileDescriptor = socket(AF_INET, SOCK_STREAM, 0);
+		if (socketFileDescriptor < 0)
+		{
+			return -1;
+		}
+
+		int enable = 1;
+		if (setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
+		{
+			close(socketFileDescriptor);
+			return -1;
+		}
+
+		int const bindResult = bind(
+			socketFileDescriptor,
+			reinterpret_cast<sockaddr*>(&socketAddress),
+			sizeof(sockaddr_in));
+		if (bindResult < 0)
+		{
+			close(socketFileDescriptor);
+			return -1;
+		}
+
+		int const listenResult = listen(socketFileDescriptor, connectionLimit);
+		if (listenResult < 0)
+		{
+			close(socketFileDescriptor);
+			return -1;
+		}
+
+		return socketFileDescriptor;
+	}
+}
+
+namespace Socket
+{
+	std::vector<char> ReadBytes(int fd, size_t limit)
+	{
+		size_t const readChunkSize = 128;
+
+		std::vector<char> buffer;
+		ssize_t totalBytesRead = 0;
+		ssize_t bytesRead = 0;
+		do
+		{
+			buffer.resize(buffer.size() + readChunkSize);
+			bytesRead = read(fd, &buffer[totalBytesRead], readChunkSize);
+			if (bytesRead < 0)
+			{
+				throw std::runtime_error("Error reading from filedescriptor");
+			}
+
+			totalBytesRead += bytesRead;
+		} while (bytesRead == readChunkSize && bytesRead < limit);
+
+		buffer.resize(totalBytesRead);
+		return buffer;
+	}
+
+	size_t WriteBytes(int fd, std::vector<char> const & bytes)
+	{
+		ssize_t totalBytesWritten = 0;
+		size_t const sizeToWrite = bytes.size();
+		while (totalBytesWritten < sizeToWrite)
+		{
+			ssize_t bytesWritten = write(fd, &bytes[totalBytesWritten], sizeToWrite - totalBytesWritten);
+			if (bytesWritten <= 0)
+			{
+				throw std::runtime_error("Error writing to filedescriptor");
+			}
+
+			totalBytesWritten += bytesWritten;
+		}
+
+		return totalBytesWritten;
+	}
+}

src/server/socket.hpp

@@ -0,0 +1,16 @@
+#pragma once
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <vector>
+
+namespace ListeningSocket
+{
+	int Create(sockaddr_in & socketAddress, int const connectionLimit);
+}
+
+namespace Socket
+{
+	std::vector<char> ReadBytes(int fd, size_t limit);
+
+	size_t WriteBytes(int fd, std::vector<char> const & bytes);
+}

src/server/socket/clientsocket.cpp

@@ -1,68 +0,0 @@
-#include "clientsocket.hpp"
-#include <stdexcept>
-#include <unistd.h>
-
-std::vector<char> ClientSocket::ReadBytes(size_t limit) const
-{
-	size_t const readChunkSize = 128;
-
-	std::vector<char> buffer;
-	ssize_t totalBytesRead = 0;
-	ssize_t bytesRead = 0;
-	do
-	{
-		buffer.resize(buffer.size() + readChunkSize);
-		bytesRead = read(fileDescriptor, &buffer[totalBytesRead], readChunkSize);
-		if (bytesRead < 0)
-		{
-			throw std::runtime_error("Error reading from filedescriptor");
-		}
-
-		totalBytesRead += bytesRead;
-	} while (bytesRead == readChunkSize && bytesRead < limit);
-
-	buffer.resize(totalBytesRead);
-	return buffer;
-}
-
-size_t ClientSocket::WriteBytes(std::vector<char> const & bytes) const
-{
-	ssize_t totalBytesWritten = 0;
-	size_t const sizeToWrite = bytes.size();
-	while (totalBytesWritten < sizeToWrite)
-	{
-		ssize_t bytesWritten = write(fileDescriptor, &bytes[totalBytesWritten], sizeToWrite - totalBytesWritten);
-		if (bytesWritten <= 0)
-		{
-			throw std::runtime_error("Error writing to filedescriptor");
-		}
-
-		totalBytesWritten += bytesWritten;
-	}
-
-	return totalBytesWritten;
-}
-
-ClientSocket::ClientSocket(int _fileDescriptor)
-	: fileDescriptor(_fileDescriptor)
-{
-	if (_fileDescriptor < 0)
-	{
-		throw std::runtime_error("clientSocket created with invalid file descriptor");
-	}
-}
-
-ClientSocket::~ClientSocket()
-{
-	if (fileDescriptor >= 0)
-	{
-		close(fileDescriptor);
-	}
-}
-
-ClientSocket::ClientSocket(ClientSocket && other)
-{
-	fileDescriptor = other.fileDescriptor;
-
-	other.fileDescriptor = -1;
-}

src/server/socket/clientsocket.hpp

@@ -1,23 +0,0 @@
-#pragma once
-#include <cstdint>
-#include <vector>
-
-class ClientSocket
-{
-private:
-	int fileDescriptor;
-
-public:
-	// Parameter limit is a multiple of 128
-	std::vector<char> ReadBytes(size_t limit = 512) const;
-
-	size_t WriteBytes(std::vector<char> const & bytes) const;
-
-	ClientSocket(int _fileDescriptor);
-	~ClientSocket();
-
-	ClientSocket(ClientSocket && other);
-
-	ClientSocket(ClientSocket & other) = delete;
-	ClientSocket & operator=(ClientSocket & other) = delete;
-};

src/server/socket/listeningsocket.cpp

@@ -1,60 +0,0 @@
-#include "listeningsocket.hpp"
-#include <stdexcept>
-#include <unistd.h>
-
-int const connectionLimit = 10;
-
-ClientSocket ListeningSocket::AcceptNextConnection()
-{
-	unsigned sockaddrSize = sizeof(sockaddr_in);
-	int connectionFileDescriptor = accept(
-		socketFileDescriptor,
-		reinterpret_cast<sockaddr *>(&socketAddress),
-		&sockaddrSize);
-	
-	return ClientSocket(connectionFileDescriptor);
-}
-
-ListeningSocket::ListeningSocket(int const port)
-	: socketFileDescriptor(-1),
-	socketAddress()
-{
-	socketFileDescriptor = socket(AF_INET, SOCK_STREAM, 0);
-	if (socketFileDescriptor < 0)
-	{
-		throw std::runtime_error("socket creation error");
-	}
-
-	int enable = 1;
-	if (setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
-	{
-		throw std::runtime_error("setsockopt SO_REUSEADDR failed");
-	}
-
-	socketAddress.sin_family = AF_INET;
-	socketAddress.sin_addr.s_addr = INADDR_ANY;
-	socketAddress.sin_port = htons(port);
-
-	int const bindResult = bind(
-		socketFileDescriptor,
-		reinterpret_cast<sockaddr*>(&socketAddress),
-		sizeof(sockaddr_in));
-	if (bindResult < 0)
-	{
-		throw std::runtime_error("socket bind error code " + std::to_string(errno));
-	}
-
-	int const listenResult = listen(socketFileDescriptor, connectionLimit);
-	if (listenResult < 0)
-	{
-		throw std::runtime_error("socket listening error");
-	}
-}
-
-ListeningSocket::~ListeningSocket()
-{
-	if (socketFileDescriptor >= 0)
-	{
-		close(socketFileDescriptor);
-	}
-}

src/server/socket/listeningsocket.hpp

@@ -1,20 +0,0 @@
-#pragma once
-#include "clientsocket.hpp"
-#include <sys/socket.h>
-#include <netinet/in.h>
-
-class ListeningSocket
-{
-private:
-	int socketFileDescriptor;
-	sockaddr_in socketAddress;
-
-public:
-	ClientSocket AcceptNextConnection();
-
-	ListeningSocket(int const port);
-	~ListeningSocket();
-
-	ListeningSocket(ListeningSocket & other) = delete;
-	ListeningSocket & operator=(ListeningSocket & other) = delete;
-};