feat: add server example

Signed-off-by: ZhangJian He <shoothzj@gmail.com>

examples/server/server.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"log/slog"
+	"opcua-go/opcua"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+)
+
+func main() {
+	logger := slog.Default()
+
+	config := &opcua.ServerConfig{
+		Host:               "127.0.0.1",
+		Port:               4840,
+		ReceiverBufferSize: 1024,
+		ReadTimeout:        5 * time.Second,
+		Logger:             logger,
+	}
+
+	server := opcua.NewServer(config)
+
+	port, err := server.Run()
+	if err != nil {
+		logger.Error("Failed to start server", slog.String("error", err.Error()))
+		os.Exit(1)
+	}
+
+	logger.Info("Server running", slog.Int("port", port))
+
+	signalChan := make(chan os.Signal, 1)
+	signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)
+
+	<-signalChan
+	logger.Info("Shutting down server...")
+
+	if err := server.Close(); err != nil {
+		logger.Error("Error closing server", slog.String("error", err.Error()))
+	} else {
+		logger.Info("Server stopped gracefully")
+	}
+}

go.mod

@@ -2,7 +2,10 @@ module opcua-go
 
 go 1.21
 
-require github.com/stretchr/testify v1.9.0
+require (
+	github.com/shoothzj/gox v0.0.3-0.20240910014233-77c917119f05
+	github.com/stretchr/testify v1.9.0
+)
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect

go.sum

@@ -2,6 +2,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/shoothzj/gox v0.0.3-0.20240910014233-77c917119f05 h1:1WadlKXqm14AU5fUFP29Zxdsn/oDwvVoz6CUhv5u7/M=
+github.com/shoothzj/gox v0.0.3-0.20240910014233-77c917119f05/go.mod h1:W8vthsaC2LWvu1zy/B9znKuOOSrFUqWCMHkdbqZJE04=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

opcua/server.go

@@ -1,17 +1,24 @@
 package opcua
 
 import (
+	"encoding/binary"
 	"fmt"
+	"github.com/shoothzj/gox/buffer"
 	"log/slog"
 	"net"
 	"sync"
+	"time"
 )
 
 type ServerConfig struct {
 	Host string
 	Port int
 
-	logger *slog.Logger
+	ReceiverBufferSize int
+
+	ReadTimeout time.Duration
+
+	Logger *slog.Logger
 }
 
 func (s *ServerConfig) addr() string {
@@ -32,7 +39,7 @@ func NewServer(config *ServerConfig) *Server {
 	server := &Server{
 		config: config,
 		quit:   make(chan bool),
-		logger: config.logger,
+		logger: config.Logger,
 	}
 	server.logger.Info("server initialized", slog.String("host", config.Host), slog.Int("port", config.Port))
 	return server
@@ -80,12 +87,56 @@ func (s *Server) listenLoop() {
 			}
 		}
 		go func() {
-			s.handleConn(netConn)
+			s.handleConn(&opcuaConn{
+				conn:   netConn,
+				buffer: buffer.NewBuffer(s.config.ReceiverBufferSize),
+			})
 		}()
 	}
 }
 
-func (s *Server) handleConn(conn net.Conn) {
+type opcuaConn struct {
+	conn   net.Conn
+	buffer *buffer.Buffer
+}
+
+func (s *Server) handleConn(conn *opcuaConn) {
+	for {
+		if s.config.ReadTimeout > 0 {
+			_ = conn.conn.SetReadDeadline(time.Now().Add(s.config.ReadTimeout))
+		}
+		readLen, err := conn.conn.Read(conn.buffer.WritableSlice())
+		if err != nil {
+			break
+		}
+		err = conn.buffer.AdjustWriteCursor(readLen)
+		if err != nil {
+			break
+		}
+		for {
+			if conn.buffer.Size() < 8 {
+				break
+			}
+
+			header := make([]byte, 8)
+			_, err = conn.buffer.Peek(header)
+			if err != nil {
+				break
+			}
+
+			messageLen := int(binary.LittleEndian.Uint32(header[4:8]))
+
+			if conn.buffer.Size() < messageLen {
+				break
+			}
+
+			bytes := make([]byte, messageLen)
+			err = conn.buffer.ReadExactly(bytes)
+			if err != nil {
+				break
+			}
+		}
+	}
 }
 
 func (s *Server) Close() error {

opcua/server_test.go

@@ -11,7 +11,7 @@ func TestStartWithZeroPort(t *testing.T) {
 	config := &ServerConfig{
 		Host:   "localhost",
 		Port:   0,
-		logger: slog.Default(),
+		Logger: slog.Default(),
 	}
 
 	server := NewServer(config)