LibCore+Userland: Convert TCPServer to use the Serenity Stream API

This is intended as a real-usecase test of the Serenity Stream API, and
seemed like a good candidate due to its low amount of users.

Userland/Libraries/LibCore/TCPServer.cpp

@@ -75,7 +75,7 @@ void TCPServer::set_blocking(bool blocking)
     VERIFY(flags == 0);
 }
 
-RefPtr<TCPSocket> TCPServer::accept()
+ErrorOr<Stream::TCPSocket> TCPServer::accept()
 {
     VERIFY(m_listening);
     sockaddr_in in;
@@ -87,17 +87,20 @@ RefPtr<TCPSocket> TCPServer::accept()
 #endif
 
     if (accepted_fd < 0) {
-        perror("accept");
-        return nullptr;
+        return Error::from_errno(errno);
     }
 
+    auto socket = TRY(Stream::TCPSocket::adopt_fd(accepted_fd));
+
 #ifdef AK_OS_MACOS
-    int option = 1;
-    (void)ioctl(m_fd, FIONBIO, &option);
-    (void)fcntl(accepted_fd, F_SETFD, FD_CLOEXEC);
+    // FIXME: Ideally, we should let the caller decide whether it wants the
+    //        socket to be nonblocking or not, but there are currently places
+    //        which depend on this.
+    TRY(socket.set_blocking(false));
+    TRY(socket.set_close_on_exec(true));
 #endif
 
-    return TCPSocket::construct(accepted_fd);
+    return socket;
 }
 
 Optional<IPv4Address> TCPServer::local_address() const

Userland/Libraries/LibCore/TCPServer.h

@@ -9,6 +9,7 @@
 #include <AK/IPv4Address.h>
 #include <LibCore/Notifier.h>
 #include <LibCore/Object.h>
+#include <LibCore/Stream.h>
 
 namespace Core {
 
@@ -21,7 +22,7 @@ public:
     bool listen(const IPv4Address& address, u16 port);
     void set_blocking(bool blocking);
 
-    RefPtr<TCPSocket> accept();
+    ErrorOr<Stream::TCPSocket> accept();
 
     Optional<IPv4Address> local_address() const;
     Optional<u16> local_port() const;

Userland/Services/EchoServer/Client.cpp

@@ -5,34 +5,52 @@
  */
 
 #include "Client.h"
+#include "LibCore/EventLoop.h"
 
-Client::Client(int id, RefPtr<Core::TCPSocket> socket)
+Client::Client(int id, Core::Stream::TCPSocket socket)
     : m_id(id)
     , m_socket(move(socket))
 {
-    m_socket->on_ready_to_read = [this] { drain_socket(); };
+    m_socket.on_ready_to_read = [this] {
+        if (m_socket.is_eof())
+            return;
+
+        auto result = drain_socket();
+        if (result.is_error()) {
+            dbgln("Failed while trying to drain the socket: {}", result.error());
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        }
+    };
 }
 
-void Client::drain_socket()
+ErrorOr<void> Client::drain_socket()
 {
     NonnullRefPtr<Client> protect(*this);
-    while (m_socket->can_read()) {
-        auto buf = m_socket->read(1024);
 
-        dbgln("Read {} bytes.", buf.size());
+    auto maybe_buffer = ByteBuffer::create_uninitialized(1024);
+    if (!maybe_buffer.has_value())
+        return ENOMEM;
+    auto buffer = maybe_buffer.release_value();
 
-        if (m_socket->eof()) {
-            quit();
+    while (TRY(m_socket.can_read_without_blocking())) {
+        auto nread = TRY(m_socket.read(buffer));
+
+        dbgln("Read {} bytes.", nread);
+
+        if (m_socket.is_eof()) {
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
             break;
         }
 
-        m_socket->write(buf);
+        TRY(m_socket.write({ buffer.data(), nread }));
     }
+
+    return {};
 }
 
 void Client::quit()
 {
-    m_socket->close();
+    m_socket.close();
     if (on_exit)
         on_exit();
 }

Userland/Services/EchoServer/Client.h

@@ -6,11 +6,11 @@
 
 #pragma once
 
-#include <LibCore/TCPSocket.h>
+#include <LibCore/Stream.h>
 
 class Client : public RefCounted<Client> {
 public:
-    static NonnullRefPtr<Client> create(int id, RefPtr<Core::TCPSocket> socket)
+    static NonnullRefPtr<Client> create(int id, Core::Stream::TCPSocket socket)
     {
         return adopt_ref(*new Client(id, move(socket)));
     }
@@ -18,12 +18,12 @@ public:
     Function<void()> on_exit;
 
 protected:
-    Client(int id, RefPtr<Core::TCPSocket> socket);
+    Client(int id, Core::Stream::TCPSocket socket);
 
-    void drain_socket();
+    ErrorOr<void> drain_socket();
     void quit();
 
 private:
     int m_id { 0 };
-    RefPtr<Core::TCPSocket> m_socket;
+    Core::Stream::TCPSocket m_socket;
 };

Userland/Services/EchoServer/main.cpp

@@ -52,15 +52,15 @@ int main(int argc, char** argv)
     server->on_ready_to_accept = [&next_id, &clients, &server] {
         int id = next_id++;
 
-        auto client_socket = server->accept();
-        if (!client_socket) {
-            perror("accept");
+        auto maybe_client_socket = server->accept();
+        if (maybe_client_socket.is_error()) {
+            warnln("accept: {}", maybe_client_socket.error());
             return;
         }
 
         outln("Client {} connected", id);
 
-        auto client = Client::create(id, move(client_socket));
+        auto client = Client::create(id, maybe_client_socket.release_value());
         client->on_exit = [&clients, id] {
             Core::deferred_invoke([&clients, id] {
                 clients.remove(id);

Userland/Services/TelnetServer/Client.cpp

@@ -11,59 +11,100 @@
 #include <AK/StringBuilder.h>
 #include <AK/StringView.h>
 #include <AK/Types.h>
+#include <LibCore/EventLoop.h>
 #include <LibCore/Notifier.h>
-#include <LibCore/TCPSocket.h>
 #include <stdio.h>
 #include <unistd.h>
 
-Client::Client(int id, RefPtr<Core::TCPSocket> socket, int ptm_fd)
+Client::Client(int id, Core::Stream::TCPSocket socket, int ptm_fd)
     : m_id(id)
     , m_socket(move(socket))
     , m_ptm_fd(ptm_fd)
     , m_ptm_notifier(Core::Notifier::construct(ptm_fd, Core::Notifier::Read))
 {
-    m_socket->on_ready_to_read = [this] { drain_socket(); };
-    m_ptm_notifier->on_ready_to_read = [this] { drain_pty(); };
-    m_parser.on_command = [this](const Command& command) { handle_command(command); };
+    m_socket.on_ready_to_read = [this] {
+        auto result = drain_socket();
+        if (result.is_error()) {
+            dbgln("Failed to drain the socket: {}", result.error());
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        }
+    };
+
+    m_ptm_notifier->on_ready_to_read = [this] {
+        auto result = drain_pty();
+        if (result.is_error()) {
+            dbgln("Failed to drain the PTY: {}", result.error());
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        }
+    };
+
+    m_parser.on_command = [this](const Command& command) {
+        auto result = handle_command(command);
+        if (result.is_error()) {
+            dbgln("Failed to handle the command: {}", result.error());
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        }
+    };
+
     m_parser.on_data = [this](StringView data) { handle_data(data); };
     m_parser.on_error = [this]() { handle_error(); };
-    send_commands({
+}
+
+ErrorOr<NonnullRefPtr<Client>> Client::create(int id, Core::Stream::TCPSocket socket, int ptm_fd)
+{
+    auto client = adopt_ref(*new Client(id, move(socket), ptm_fd));
+
+    auto result = client->send_commands({
         { CMD_WILL, SUB_SUPPRESS_GO_AHEAD },
         { CMD_WILL, SUB_ECHO },
         { CMD_DO, SUB_SUPPRESS_GO_AHEAD },
         { CMD_DONT, SUB_ECHO },
     });
+    if (result.is_error()) {
+        client->quit();
+        return result.release_error();
+    }
+
+    return client;
 }
 
-void Client::drain_socket()
+ErrorOr<void> Client::drain_socket()
 {
     NonnullRefPtr<Client> protect(*this);
-    while (m_socket->can_read()) {
-        auto buf = m_socket->read(1024);
 
-        m_parser.write(buf);
+    auto maybe_buffer = ByteBuffer::create_uninitialized(1024);
+    if (!maybe_buffer.has_value())
+        return ENOMEM;
+    auto buffer = maybe_buffer.release_value();
 
-        if (m_socket->eof()) {
-            quit();
+    while (TRY(m_socket.can_read_without_blocking())) {
+        auto nread = TRY(m_socket.read(buffer));
+
+        m_parser.write({ buffer.data(), nread });
+
+        if (m_socket.is_eof()) {
+            Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
             break;
         }
     }
+
+    return {};
 }
 
-void Client::drain_pty()
+ErrorOr<void> Client::drain_pty()
 {
     u8 buffer[BUFSIZ];
     ssize_t nread = read(m_ptm_fd, buffer, sizeof(buffer));
     if (nread < 0) {
-        perror("read(ptm)");
-        quit();
-        return;
+        Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        return static_cast<ErrnoCode>(errno);
     }
     if (nread == 0) {
-        quit();
-        return;
+        Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
+        return {};
     }
-    send_data(StringView(buffer, (size_t)nread));
+
+    return send_data({ buffer, (size_t)nread });
 }
 
 void Client::handle_data(StringView data)
@@ -71,7 +112,7 @@ void Client::handle_data(StringView data)
     write(m_ptm_fd, data.characters_without_null_termination(), data.length());
 }
 
-void Client::handle_command(const Command& command)
+ErrorOr<void> Client::handle_command(const Command& command)
 {
     switch (command.command) {
     case CMD_DO:
@@ -87,10 +128,10 @@ void Client::handle_command(const Command& command)
         case SUB_ECHO:
             // we always want to be the ones in control of the output. tell
             // the client to disable local echo.
-            send_command({ CMD_DONT, SUB_ECHO });
+            TRY(send_command({ CMD_DONT, SUB_ECHO }));
             break;
         case SUB_SUPPRESS_GO_AHEAD:
-            send_command({ CMD_DO, SUB_SUPPRESS_GO_AHEAD });
+            TRY(send_command({ CMD_DO, SUB_SUPPRESS_GO_AHEAD }));
             break;
         default:
             // don't respond to unknown commands
@@ -102,14 +143,16 @@ void Client::handle_command(const Command& command)
         // won't do.
         break;
     }
+
+    return {};
 }
 
 void Client::handle_error()
 {
-    quit();
+    Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
 }
 
-void Client::send_data(StringView data)
+ErrorOr<void> Client::send_data(StringView data)
 {
     bool fast = true;
     for (size_t i = 0; i < data.length(); i++) {
@@ -119,8 +162,8 @@ void Client::send_data(StringView data)
     }
 
     if (fast) {
-        m_socket->write(data);
-        return;
+        TRY(m_socket.write({ data.characters_without_null_termination(), data.length() }));
+        return {};
     }
 
     StringBuilder builder;
@@ -140,31 +183,37 @@ void Client::send_data(StringView data)
         }
     }
 
-    m_socket->write(builder.to_string());
+    auto builder_contents = builder.to_byte_buffer();
+    TRY(m_socket.write(builder_contents));
+    return {};
 }
 
-void Client::send_command(Command command)
+ErrorOr<void> Client::send_command(Command command)
 {
-    send_commands({ command });
+    return send_commands({ command });
 }
 
-void Client::send_commands(Vector<Command> commands)
+ErrorOr<void> Client::send_commands(Vector<Command> commands)
 {
-    auto buffer = ByteBuffer::create_uninitialized(commands.size() * 3).release_value(); // FIXME: Handle possible OOM situation.
+    auto maybe_buffer = ByteBuffer::create_uninitialized(commands.size() * 3);
+    if (!maybe_buffer.has_value())
+        return ENOMEM;
+    auto buffer = maybe_buffer.release_value();
     OutputMemoryStream stream { buffer };
 
     for (auto& command : commands)
         stream << (u8)IAC << command.command << command.subcommand;
 
     VERIFY(stream.is_end());
-    m_socket->write(buffer.data(), buffer.size());
+    TRY(m_socket.write({ buffer.data(), buffer.size() }));
+    return {};
 }
 
 void Client::quit()
 {
     m_ptm_notifier->set_enabled(false);
     close(m_ptm_fd);
-    m_socket->close();
+    m_socket.close();
     if (on_exit)
         on_exit();
 }

Userland/Services/TelnetServer/Client.h

@@ -10,38 +10,35 @@
 #include <AK/StringView.h>
 #include <AK/Types.h>
 #include <LibCore/Notifier.h>
-#include <LibCore/TCPSocket.h>
+#include <LibCore/Stream.h>
 
 #include "Command.h"
 #include "Parser.h"
 
 class Client : public RefCounted<Client> {
 public:
-    static NonnullRefPtr<Client> create(int id, RefPtr<Core::TCPSocket> socket, int ptm_fd)
-    {
-        return adopt_ref(*new Client(id, move(socket), ptm_fd));
-    }
+    static ErrorOr<NonnullRefPtr<Client>> create(int id, Core::Stream::TCPSocket socket, int ptm_fd);
 
     Function<void()> on_exit;
 
-protected:
-    Client(int id, RefPtr<Core::TCPSocket> socket, int ptm_fd);
+private:
+    Client(int id, Core::Stream::TCPSocket socket, int ptm_fd);
+
+    ErrorOr<void> drain_socket();
+    ErrorOr<void> drain_pty();
+    ErrorOr<void> handle_command(Command const& command);
+    ErrorOr<void> send_data(StringView str);
+    ErrorOr<void> send_command(Command command);
+    ErrorOr<void> send_commands(Vector<Command> commands);
 
-    void drain_socket();
-    void drain_pty();
     void handle_data(StringView);
-    void handle_command(const Command& command);
     void handle_error();
-    void send_data(StringView str);
-    void send_command(Command command);
-    void send_commands(Vector<Command> commands);
     void quit();
 
-private:
     // client id
     int m_id { 0 };
     // client resources
-    RefPtr<Core::TCPSocket> m_socket;
+    Core::Stream::TCPSocket m_socket;
     Parser m_parser;
     // pty resources
     int m_ptm_fd { -1 };

Userland/Services/TelnetServer/main.cpp

@@ -109,32 +109,39 @@ int main(int argc, char** argv)
     server->on_ready_to_accept = [&next_id, &clients, &server, command] {
         int id = next_id++;
 
-        auto client_socket = server->accept();
-        if (!client_socket) {
-            perror("accept");
+        ErrorOr<Core::Stream::TCPSocket> maybe_client_socket = server->accept();
+        if (maybe_client_socket.is_error()) {
+            warnln("accept: {}", maybe_client_socket.error());
             return;
         }
+        auto client_socket = maybe_client_socket.release_value();
 
         int ptm_fd = posix_openpt(O_RDWR);
         if (ptm_fd < 0) {
             perror("posix_openpt");
-            client_socket->close();
+            client_socket.close();
             return;
         }
         if (grantpt(ptm_fd) < 0) {
             perror("grantpt");
-            client_socket->close();
+            client_socket.close();
             return;
         }
         if (unlockpt(ptm_fd) < 0) {
             perror("unlockpt");
-            client_socket->close();
+            client_socket.close();
             return;
         }
 
         run_command(ptm_fd, command);
 
-        auto client = Client::create(id, move(client_socket), ptm_fd);
+        auto maybe_client = Client::create(id, move(client_socket), ptm_fd);
+        if (maybe_client.is_error()) {
+            warnln("Failed to create the client: {}", maybe_client.error());
+            return;
+        }
+
+        auto client = maybe_client.release_value();
         client->on_exit = [&clients, id] {
             Core::deferred_invoke([&clients, id] { clients.remove(id); });
         };

Userland/Services/WebServer/Client.cpp

@@ -28,41 +28,75 @@
 
 namespace WebServer {
 
-Client::Client(NonnullRefPtr<Core::TCPSocket> socket, Core::Object* parent)
+Client::Client(Core::Stream::BufferedTCPSocket socket, Core::Object* parent)
     : Core::Object(parent)
-    , m_socket(socket)
+    , m_socket(move(socket))
 {
 }
 
 void Client::die()
 {
+    m_socket.close();
     deferred_invoke([this] { remove_from_parent(); });
 }
 
 void Client::start()
 {
-    m_socket->on_ready_to_read = [this] {
+    m_socket.on_ready_to_read = [this] {
         StringBuilder builder;
+
+        auto maybe_buffer = ByteBuffer::create_uninitialized(m_socket.buffer_size());
+        if (!maybe_buffer.has_value()) {
+            warnln("Could not create buffer for client (possibly out of memory)");
+            die();
+            return;
+        }
+
+        auto buffer = maybe_buffer.release_value();
         for (;;) {
-            auto line = m_socket->read_line();
-            if (line.is_empty())
+            auto maybe_can_read = m_socket.can_read_without_blocking();
+            if (maybe_can_read.is_error()) {
+                warnln("Failed to get the blocking status for the socket: {}", maybe_can_read.error());
+                die();
+                return;
+            }
+
+            if (!maybe_can_read.value())
                 break;
-            builder.append(line);
+
+            auto maybe_nread = m_socket.read_until_any_of(buffer, Array { "\r"sv, "\n"sv, "\r\n"sv });
+            if (maybe_nread.is_error()) {
+                warnln("Failed to read a line from the request: {}", maybe_nread.error());
+                die();
+                return;
+            }
+
+            if (m_socket.is_eof()) {
+                die();
+                break;
+            }
+
+            builder.append(StringView { buffer.data(), maybe_nread.value() });
             builder.append("\r\n");
         }
 
         auto request = builder.to_byte_buffer();
         dbgln_if(WEBSERVER_DEBUG, "Got raw request: '{}'", String::copy(request));
-        handle_request(request);
+
+        auto maybe_did_handle = handle_request(request);
+        if (maybe_did_handle.is_error()) {
+            warnln("Failed to handle the request: {}", maybe_did_handle.error());
+        }
+
         die();
     };
 }
 
-void Client::handle_request(ReadonlyBytes raw_request)
+ErrorOr<bool> Client::handle_request(ReadonlyBytes raw_request)
 {
     auto request_or_error = HTTP::HttpRequest::from_raw_request(raw_request);
     if (!request_or_error.has_value())
-        return;
+        return false;
     auto& request = request_or_error.value();
 
     if constexpr (WEBSERVER_DEBUG) {
@@ -73,16 +107,16 @@ void Client::handle_request(ReadonlyBytes raw_request)
     }
 
     if (request.method() != HTTP::HttpRequest::Method::GET) {
-        send_error_response(501, request);
-        return;
+        TRY(send_error_response(501, request));
+        return false;
     }
 
     // Check for credentials if they are required
     if (Configuration::the().credentials().has_value()) {
         bool has_authenticated = verify_credentials(request.headers());
         if (!has_authenticated) {
-            send_error_response(401, request, { "WWW-Authenticate: Basic realm=\"WebServer\", charset=\"UTF-8\"" });
-            return;
+            TRY(send_error_response(401, request, { "WWW-Authenticate: Basic realm=\"WebServer\", charset=\"UTF-8\"" }));
+            return false;
         }
     }
 
@@ -102,8 +136,8 @@ void Client::handle_request(ReadonlyBytes raw_request)
             red.append(requested_path);
             red.append("/");
 
-            send_redirect(red.to_string(), request);
-            return;
+            TRY(send_redirect(red.to_string(), request));
+            return true;
         }
 
         StringBuilder index_html_path_builder;
@@ -111,29 +145,30 @@ void Client::handle_request(ReadonlyBytes raw_request)
         index_html_path_builder.append("/index.html");
         auto index_html_path = index_html_path_builder.to_string();
         if (!Core::File::exists(index_html_path)) {
-            handle_directory_listing(requested_path, real_path, request);
-            return;
+            TRY(handle_directory_listing(requested_path, real_path, request));
+            return true;
         }
         real_path = index_html_path;
     }
 
     auto file = Core::File::construct(real_path);
     if (!file->open(Core::OpenMode::ReadOnly)) {
-        send_error_response(404, request);
-        return;
+        TRY(send_error_response(404, request));
+        return false;
     }
 
     if (file->is_device()) {
-        send_error_response(403, request);
-        return;
+        TRY(send_error_response(403, request));
+        return false;
     }
 
     Core::InputFileStream stream { file };
 
-    send_response(stream, request, Core::guess_mime_type_based_on_filename(real_path));
+    TRY(send_response(stream, request, Core::guess_mime_type_based_on_filename(real_path)));
+    return true;
 }
 
-void Client::send_response(InputStream& response, HTTP::HttpRequest const& request, String const& content_type)
+ErrorOr<void> Client::send_response(InputStream& response, HTTP::HttpRequest const& request, String const& content_type)
 {
     StringBuilder builder;
     builder.append("HTTP/1.0 200 OK\r\n");
@@ -146,7 +181,8 @@ void Client::send_response(InputStream& response, HTTP::HttpRequest const& reque
     builder.append("\r\n");
     builder.append("\r\n");
 
-    m_socket->write(builder.to_string());
+    auto builder_contents = builder.to_byte_buffer();
+    TRY(m_socket.write(builder_contents));
     log_response(200, request);
 
     char buffer[PAGE_SIZE];
@@ -155,11 +191,22 @@ void Client::send_response(InputStream& response, HTTP::HttpRequest const& reque
         if (response.unreliable_eof() && size == 0)
             break;
 
-        m_socket->write({ buffer, size });
+        ReadonlyBytes write_buffer { buffer, size };
+        while (!write_buffer.is_empty()) {
+            auto nwritten = TRY(m_socket.write(write_buffer));
+
+            if (nwritten == 0) {
+                dbgln("EEEEEE got 0 bytes written!");
+            }
+
+            write_buffer = write_buffer.slice(nwritten);
+        }
     } while (true);
+
+    return {};
 }
 
-void Client::send_redirect(StringView redirect_path, HTTP::HttpRequest const& request)
+ErrorOr<void> Client::send_redirect(StringView redirect_path, HTTP::HttpRequest const& request)
 {
     StringBuilder builder;
     builder.append("HTTP/1.0 301 Moved Permanently\r\n");
@@ -168,9 +215,11 @@ void Client::send_redirect(StringView redirect_path, HTTP::HttpRequest const& re
     builder.append("\r\n");
     builder.append("\r\n");
 
-    m_socket->write(builder.to_string());
+    auto builder_contents = builder.to_byte_buffer();
+    TRY(m_socket.write(builder_contents));
 
     log_response(301, request);
+    return {};
 }
 
 static String folder_image_data()
@@ -195,7 +244,7 @@ static String file_image_data()
     return cache;
 }
 
-void Client::handle_directory_listing(String const& requested_path, String const& real_path, HTTP::HttpRequest const& request)
+ErrorOr<void> Client::handle_directory_listing(String const& requested_path, String const& real_path, HTTP::HttpRequest const& request)
 {
     StringBuilder builder;
 
@@ -270,10 +319,10 @@ void Client::handle_directory_listing(String const& requested_path, String const
 
     auto response = builder.to_string();
     InputMemoryStream stream { response.bytes() };
-    send_response(stream, request, "text/html");
+    return send_response(stream, request, "text/html");
 }
 
-void Client::send_error_response(unsigned code, HTTP::HttpRequest const& request, Vector<String> const& headers)
+ErrorOr<void> Client::send_error_response(unsigned code, HTTP::HttpRequest const& request, Vector<String> const& headers)
 {
     auto reason_phrase = HTTP::HttpResponse::reason_phrase_for_code(code);
     StringBuilder builder;
@@ -292,9 +341,12 @@ void Client::send_error_response(unsigned code, HTTP::HttpRequest const& request
     builder.appendff("{} ", code);
     builder.append(reason_phrase);
     builder.append("</h1></body></html>");
-    m_socket->write(builder.to_string());
+
+    auto builder_contents = builder.to_byte_buffer();
+    TRY(m_socket.write(builder_contents));
 
     log_response(code, request);
+    return {};
 }
 
 void Client::log_response(unsigned code, HTTP::HttpRequest const& request)

Userland/Services/WebServer/Client.h

@@ -7,8 +7,9 @@
 #pragma once
 
 #include <LibCore/Object.h>
-#include <LibCore/TCPSocket.h>
+#include <LibCore/Stream.h>
 #include <LibHTTP/Forward.h>
+#include <LibHTTP/HttpRequest.h>
 
 namespace WebServer {
 
@@ -19,18 +20,18 @@ public:
     void start();
 
 private:
-    Client(NonnullRefPtr<Core::TCPSocket>, Core::Object* parent);
+    Client(Core::Stream::BufferedTCPSocket, Core::Object* parent);
 
-    void handle_request(ReadonlyBytes);
-    void send_response(InputStream&, HTTP::HttpRequest const&, String const& content_type);
-    void send_redirect(StringView redirect, HTTP::HttpRequest const&);
-    void send_error_response(unsigned code, HTTP::HttpRequest const&, Vector<String> const& headers = {});
+    ErrorOr<bool> handle_request(ReadonlyBytes);
+    ErrorOr<void> send_response(InputStream&, HTTP::HttpRequest const&, String const& content_type);
+    ErrorOr<void> send_redirect(StringView redirect, HTTP::HttpRequest const&);
+    ErrorOr<void> send_error_response(unsigned code, HTTP::HttpRequest const&, Vector<String> const& headers = {});
     void die();
     void log_response(unsigned code, HTTP::HttpRequest const&);
-    void handle_directory_listing(String const& requested_path, String const& real_path, HTTP::HttpRequest const&);
+    ErrorOr<void> handle_directory_listing(String const& requested_path, String const& real_path, HTTP::HttpRequest const&);
     bool verify_credentials(Vector<HTTP::HttpRequest::Header> const&);
 
-    NonnullRefPtr<Core::TCPSocket> m_socket;
+    Core::Stream::BufferedTCPSocket m_socket;
 };
 
 }

Userland/Services/WebServer/main.cpp

@@ -72,9 +72,20 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto server = TRY(Core::TCPServer::try_create());
 
     server->on_ready_to_accept = [&] {
-        auto client_socket = server->accept();
-        VERIFY(client_socket);
-        auto client = WebServer::Client::construct(client_socket.release_nonnull(), server);
+        auto maybe_client_socket = server->accept();
+        if (maybe_client_socket.is_error()) {
+            warnln("Failed to accept the client: {}", maybe_client_socket.error());
+            return;
+        }
+
+        auto maybe_buffered_socket = Core::Stream::BufferedTCPSocket::create(maybe_client_socket.release_value());
+        if (maybe_buffered_socket.is_error()) {
+            warnln("Could not obtain a buffered socket for the client: {}", maybe_buffered_socket.error());
+            return;
+        }
+
+        VERIFY(!maybe_buffered_socket.value().set_blocking(true).is_error());
+        auto client = WebServer::Client::construct(maybe_buffered_socket.release_value(), server);
         client->start();
     };