Use of the NET packet TCP socket in the Go language

First, through the socket we mock request NetEase

Package Main;import ("NET" "Log" "Io/ioutil" "FMT") Func Chkerror (err error) {if err! = Nil {log. Fatal (err);}} Func Main () {///We mock request NetEase server//resolvetcpaddr used to get a tcpaddr//net parameter is "TCP4", "TCP6", "tcp"//addr means domain name or IP address plus port number tcpaddr, ERR: = Net. RESOLVETCPADDR ("TCP4", "www.163.com:80"); Chkerror (err);//dialtcp establishes a TCP connection//net parameter is "TCP4", "TCP6", "TCP"// LADDR represents a native address, typically set to NIL//RADDR for remote address tcpconn, ERR2: = Net. DIALTCP ("TCP", Nil, tcpaddr), Chkerror (ERR2),//write data to Tcpconn, ERR3: = Tcpconn. Write ([]byte ("get/http/1.1 \r\n\r\n")); Chkerror (ERR3);//Read all data in Tcpconn, ERR4: = Ioutil. ReadAll (Tcpconn); Chkerror (ERR4);//print out data fmt. Println (String (data));}

　

Second, create a simple server through the socket

Package Main;import ("NET" "Log") Func Chkerror (err error) {if err! = Nil {log. Fatal (err);}} Func Main () {//Creates a TCP server-side tcpaddr, err: = Net. RESOLVETCPADDR ("TCP4", "127.0.0.1:8080"); Chkerror (err);//Listener Port Tcplisten, ERR2: = Net. LISTENTCP ("TCP", tcpaddr); Chkerror (ERR2);//The processing of a dead loop client requests for {//waits for a client's connection//Note here is conn that cannot concurrently handle multiple requests, ERR3: = Tcplisten. Accept ();//If there is an error directly skip if ERR3! = nil {continue;} Send data to the client and close the connection conn. Write ([]byte ("hello,client \ r \ n")]; Conn. Close ();}}

Test by Xshell's Telnet method.

Third, improve the above code, using Goroutine to process the user's request

Package Main;import ("Log" "NET" "Time") Func Chkerror (err error) {if err! = Nil {log. Fatal (err);}} Handle client requests separately Func CLIENTHANDLE (conn net). Conn) {defer Conn. Close (); Conn. Write ([]byte ("Hello" + time. Now (). String ()));} Func Main () {//Creates a TCP server-side tcpaddr, err: = Net. RESOLVETCPADDR ("TCP4", "127.0.0.1:8080"); Chkerror (err);//Listener Port Tcplisten, ERR2: = Net. LISTENTCP ("TCP", tcpaddr); Chkerror (ERR2);//The Processing of the dead loop client requests for {//waits for the client's connection conn, err3: = Tcplisten. Accept ();//If there is an error directly skip if ERR3! = nil {continue;} Handle user requests via Goroutine go Clienthandle (conn);}}

Four, continuous processing of requests sent by the client, according to the cmd command, different data returned.

Package Main;import ("NET" "Time" "Log" "strings") Func Chkerror (err error) {if err! = Nil {log. Fatal (err);}} Handle client requests separately Func CLIENTHANDLE (conn net). Conn) {//set to automatically turn off Connconn when the client has no data request within 3 minutes. Setreaddeadline (time. Now (). ADD (time. Minute * 3));D Efer Conn. Close ();//cyclic processing of the client's request for {data: = make ([]byte, 256);//read data from Conn N, err: = conn. Read (data)//If the read data size is 0 or an error exits if n = = 0 | | Err! = nil {break;} Remove both whitespace character cmd: = strings. Trimspace (String (data[0:n]));//data sent to the client Rep: = ""; if (cmd = = "string") {rep = "hello,client \ r \ n";} else if (cmd = = "Time") {rep = time. Now (). Format ("2006-01-02 15:04:05"); Send Data Conn. Write ([]byte (Rep));}} Func Main () {tcpaddr, err: = Net. RESOLVETCPADDR ("TCP4", "127.0.0.1:8080"); Chkerror (err); Tcplisten, ERR2: = Net. LISTENTCP ("TCP", tcpaddr); Chkerror (ERR2); for {conn, err3: = Tcplisten. Accept (); if err3! = nil {continue;} Go Clienthandle (conn);}}

Use of the NET packet TCP socket in the Go language