A simple yet quite practical golang socket server/client framework especially convenient for handling TCP fixed-length header and variable-length body using pure net package. Of course, it also supports udp and domain socket.
- The framework calls the user-specified callback.
- For TCP, the total size of user data is passed to the framework via a callback, and the framework does TCP buffering automatically.
- Byte data is exchanged.
- Supports TCP, UDP and Domain Socket.
go get github.com/jeremyko/gosof@latest
See the example folder for all examples.
package custom_msg
import "encoding/binary"
// user specific custom data example
// UserMsgHeader : fixed length header
type UserMsgHeader struct {
MsgTotalLen uint32 // total length of data -> header + body
MsgType [6]byte
EtcInfo [20]byte
}
var FixedHeaderSize = binary.Size(UserMsgHeader{}) // or -> const FixedHeaderSize = 4 + 6 + 20
// UserMsgBody : body of dynamic length
type UserMsgBody struct {
Field1 int
Field2 string
Field3 []byte
}package main
import (
"bufio"
"bytes"
"encoding/binary"
"encoding/gob"
custommsg "github.com/jeremyko/gosof/example/tcp/echo_custom_msg/custom_msg_def"
"github.com/jeremyko/gosof"
"log"
"os"
)
var svr gosof.Server
func main() {
svr.SetInitCompletedCb(onInitCompleted)
svr.SetNewClientCb(onNewClient)
svr.SetCalculateDataLenCb(onCalculateDataLen)
svr.SetCompleteDataCb(onCompleteData)
svr.SetDisConnectedCB(onClientDisconnected)
//lc := net.ListenConfig{
// Control: func(network, address string, conn syscall.RawConn) error {
// var operr error
// if err := conn.Control(func(fd uintptr) {
// operr = syscall.SetsockoptInt(syscall.Handle(int(fd)),
// syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1) //for windows !!
// }); err != nil {
// return err
// }
// return operr
// },
//}
//if svr.InitTcpServerListenConfig("tcp4", "127.0.0.1", 9990, &lc) != nil {
if svr.InitTcpServer("tcp4", "127.0.0.1", 9990) != nil {
log.Println("error! ", svr.GetLastErrMsg())
return
}
log.Println("press enter to exit")
input := bufio.NewScanner(os.Stdin) // wait user input to terminate
input.Scan()
}
//------------------------------------------------------------------------------
//user specific callbacks
//------------------------------------------------------------------------------
func onInitCompleted() {
log.Println("initialized") //successfully initialized.
}
func onNewClient(ctx *gosof.Context) {
log.Println("new connection : ", ctx.Conn.RemoteAddr().String())
}
func onClientDisconnected(ctx *gosof.Context, err error) {
log.Println("client disconnected : ", ctx.Conn.RemoteAddr().String(), " - ", err.Error())
}
// calculate your complete packet length here
// Return 'gosof.NeedMoreInfo' if you haven't received enough information about your data.
func onCalculateDataLen(data []byte, receivedAccumulatedLen int) (gosof.SocketOpFlag, int) {
if receivedAccumulatedLen < custommsg.FixedHeaderSize {
// Fixed-length header data has not arrived yet.
return gosof.NeedMoreInfo, 0
}
// get fixed length header
myMsgHeader := custommsg.UserMsgHeader{}
binBufHeader := bytes.Buffer{}
binBufHeader.Write(data[:receivedAccumulatedLen])
err := binary.Read(&binBufHeader, binary.LittleEndian, &myMsgHeader)
if err != nil {
log.Fatal("decode error:", err)
}
return gosof.AnalyzedCompleted, int(myMsgHeader.MsgTotalLen)
}
// your whole data has arrived.
// 'data' contains header and actual data.
func onCompleteData(ctx *gosof.Context, data []byte, packetLen int) {
// header
myMsgHeader := custommsg.UserMsgHeader{}
binBufHeader := bytes.Buffer{}
binBufHeader.Write(data[:custommsg.FixedHeaderSize])
err := binary.Read(&binBufHeader, binary.LittleEndian, &myMsgHeader)
if err != nil {
log.Fatal("decode error:", err)
}
// body
clientMsg := custommsg.UserMsgBody{}
bufDataOnly := bytes.NewBuffer(data[custommsg.FixedHeaderSize:]) //except header data
dec := gob.NewDecoder(bufDataOnly) // body of dynamic length
err = dec.Decode(&clientMsg)
if err != nil {
log.Fatal("decode error:", err)
}
log.Println(ctx.Conn.RemoteAddr().String(), " / client data : type = ", string(myMsgHeader.MsgType[:]),
" etc info =", string(myMsgHeader.EtcInfo[:]),
" / data : ==> ", clientMsg.Field1, ", ", clientMsg.Field2, ", ", string(clientMsg.Field3))
// this is a simple echo server
err = svr.SendTcp(ctx, packetLen, data)
if err != nil {
log.Println(err.Error())
}
}package main
import (
"bytes"
"encoding/binary"
"encoding/gob"
"fmt"
custommsg "github.com/jeremyko/gosof/example/tcp/echo_custom_msg/custom_msg_def"
"github.com/jeremyko/gosof"
"log"
"time"
)
var recvedCnt uint = 0
func main() {
var client gosof.Client
client.SetInitCompletedCb(onInitCompleted)
client.SetServerConnectedCb(onServerConnected)
client.SetCalculateDataLenCb(onCalculateDataLen)
client.SetCompleteDataCb(onCompleteData)
client.SetDisConnectedCB(onServerDisConnected)
log.SetFlags(log.Llongfile)
if client.InitTcpClient("tcp", "127.0.0.1", 9990, 10) != nil {
log.Println("error! ", client.GetLastErrMsg())
return
}
for i := 0; i < 1000; i++ {
go func(index int) {
var binBufHeader bytes.Buffer
var binBufBody bytes.Buffer
// fixed length header
myMsgHeader := custommsg.UserMsgHeader{}
copy(myMsgHeader.MsgType[:], "type1")
copy(myMsgHeader.EtcInfo[:], "some useful info")
// body of dynamic length
myMsg := custommsg.UserMsgBody{}
myMsg.Field1 = index
myMsg.Field2 = fmt.Sprintf("TEST %d", index)
myMsg.Field3 = []byte("byte test")
encBody := gob.NewEncoder(&binBufBody)
err := encBody.Encode(myMsg)
if err != nil {
log.Fatal("encode error:", err)
}
bodyLen := binBufBody.Len()
myMsgHeader.MsgTotalLen = uint32(custommsg.FixedHeaderSize + bodyLen)
binary.Write(&binBufHeader, binary.LittleEndian, &myMsgHeader)
//--------------------------------- send header and real data
errSend := client.SendToServer(int(myMsgHeader.MsgTotalLen),
binBufHeader.Bytes(), binBufBody.Bytes())
if errSend != nil {
log.Println(errSend.Error())
return
}
}(i)
} // for
for {
time.Sleep(1 * time.Second)
}
}
//------------------------------------------------------------------------------
//user specific callbacks
//------------------------------------------------------------------------------
func onInitCompleted() {
log.Println("initialized") //successfully initialized.
}
func onServerConnected(ctx *gosof.Context) {
log.Println("server connected : ", ctx.Conn.RemoteAddr().String())
}
func onServerDisConnected(ctx *gosof.Context, err error) {
log.Println("server disconnected : ", ctx.Conn.RemoteAddr().String(), " - ", err.Error())
}
// calculate your complete packet length here
// Return 'gosof.NeedMoreInfo' if you haven't received enough information about your data.
func onCalculateDataLen(data []byte, receivedAccumulatedLen int) (gosof.SocketOpFlag, int) {
if receivedAccumulatedLen < custommsg.FixedHeaderSize {
// Fixed-length header data has not arrived yet.
return gosof.NeedMoreInfo, 0
}
// get fixed length header
myMsgHeader := custommsg.UserMsgHeader{}
binBufHeader := bytes.Buffer{}
binBufHeader.Write(data[:custommsg.FixedHeaderSize])
err := binary.Read(&binBufHeader, binary.LittleEndian, &myMsgHeader)
if err != nil {
log.Fatal("decode error:", err)
}
return gosof.AnalyzedCompleted, int(myMsgHeader.MsgTotalLen)
}
// your whole data has arrived. The echo response sent by the server has arrived.
// 'data' contains header and actual data.
func onCompleteData(ctx *gosof.Context, data []byte, packetLen int) {
// header
myMsgHeader := custommsg.UserMsgHeader{}
binBufHeader := bytes.Buffer{}
binBufHeader.Write(data[:custommsg.FixedHeaderSize])
err := binary.Read(&binBufHeader, binary.LittleEndian, &myMsgHeader)
if err != nil {
log.Fatal("decode error:", err)
}
// body
myMsg := custommsg.UserMsgBody{}
bufDataOnly := bytes.NewBuffer(data[custommsg.FixedHeaderSize:]) //except header data
dec := gob.NewDecoder(bufDataOnly) // body of dynamic length
err = dec.Decode(&myMsg)
if err != nil {
log.Fatal("decode error:", err)
}
recvedCnt++
log.Println(" received count :", recvedCnt, " : len [", packetLen, "] ==> ",
myMsg.Field1, ", ", myMsg.Field2, ", ", string(myMsg.Field3))
}