chat.go/chatserver.go

817 lines
23 KiB
Go

package main
// TODO learn about chan chan's
// http://marcio.io/2015/07/handling-1-million-requests-per-minute-with-golang/
import (
"bufio"
"bytes"
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"flag"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"os"
"path"
"strconv"
"strings"
"sync"
"time"
"github.com/emicklei/go-restful"
"gopkg.in/yaml.v2"
)
// I'm not sure how to pass nested structs, so I de-nested this.
// TODO: Learn if passing nested structs is desirable?
type Conf struct {
Port uint `yaml:"port,omitempty"`
Mailer ConfMailer
RootPath string `yaml:"root_path,omitempty"`
}
type ConfMailer struct {
Url string `yaml:"url,omitempty"`
ApiKey string `yaml:"api_key,omitempty"`
From string `yaml:"from,omitempty"`
}
type tcpUser struct {
bufConn bufferedConn
userCount chan int
email string
}
// So we can peek at net.Conn, which we can't do natively
// https://stackoverflow.com/questions/51472020/how-to-get-the-size-of-available-tcp-data
type bufferedConn struct {
r *bufio.Reader
rout io.Reader
net.Conn
}
func newBufferedConn(c net.Conn) bufferedConn {
return bufferedConn{bufio.NewReader(c), nil, c}
}
func (b bufferedConn) Peek(n int) ([]byte, error) {
return b.r.Peek(n)
}
func (b bufferedConn) Buffered() int {
return b.r.Buffered()
}
func (b bufferedConn) Read(p []byte) (int, error) {
if b.rout != nil {
return b.rout.Read(p)
}
return b.r.Read(p)
}
// Just making these all globals right now
// because... I can clean it up later
type myMsg struct {
sender net.Conn
bytes []byte
receivedAt time.Time
channel string
email string
}
var firstMsgs chan myMsg
//var myRooms map[string](chan myMsg)
var myMsgs chan myMsg
//var myUnsortedConns map[net.Conn]bool
var newConns chan net.Conn
var newTcpChat chan bufferedConn
var authTcpChat chan tcpUser
var delTcpChat chan bufferedConn
var newHttpChat chan bufferedConn
var newHttpClient chan bufferedConn
var delHttpChat chan bufferedConn
var newAuthReqs chan authReq
var valAuthReqs chan authReq
var delAuthReqs chan authReq
func usage() {
fmt.Fprintf(os.Stderr, "\nusage: go run chatserver.go\n")
flag.PrintDefaults()
fmt.Println()
os.Exit(1)
}
// https://blog.questionable.services/article/generating-secure-random-numbers-crypto-rand/
func genAuthCode() (string, error) {
n := 12
b := make([]byte, n)
_, err := rand.Read(b)
// Note that err == nil only if we read len(b) bytes.
if err != nil {
return "", err
}
return base64.URLEncoding.EncodeToString(b), nil
}
func handleRaw(bufConn bufferedConn) {
// TODO
// What happens if this is being read from range
// when it's being added here (data race)?
// Should I use a channel here instead?
// TODO see https://jameshfisher.com/2017/04/18/golang-tcp-server.html
var email string
var code string
var authn bool
// Handle all subsequent packets
buffer := make([]byte, 1024)
for {
//fmt.Fprintf(os.Stdout, "[raw] Waiting for message...\n")
count, err := bufConn.Read(buffer)
if nil != err {
if io.EOF != err {
fmt.Fprintf(os.Stderr, "Non-EOF socket error: %s\n", err)
}
fmt.Fprintf(os.Stdout, "Ending socket\n")
delTcpChat <- bufConn
break
}
buf := buffer[:count]
// Fun fact: if the buffer's current length (not capacity) is 0
// then the Read returns 0 without error
if 0 == count {
fmt.Fprintf(os.Stdout, "Weird")
break
}
if !authn {
if "" == email {
// Indeed telnet sends CRLF as part of the message
//fmt.Fprintf(os.Stdout, "buf{%s}\n", buf[:count])
// TODO use safer email testing
email = strings.TrimSpace(string(buf[:count]))
emailParts := strings.Split(email, "@")
if 2 != len(emailParts) {
fmt.Fprintf(bufConn, "Email: ")
continue
}
// Debugging any weird characters as part of the message (just CRLF)
//fmt.Fprintf(os.Stdout, "email: '%v'\n", []byte(email))
// Just for a fun little bit of puzzah
// Note: Reaction times are about 100ms
// Procesing times are about 250ms
// Right around 300ms is about when a person literally begins to get bored (begin context switching)
// Therefore any interaction should take longer than 100ms (time to register)
// and either engage the user or complete before reaching 300ms (not yet bored)
// This little ditty is meant to act as a psuedo-progress bar to engage the user
// Aside: a keystroke typically takes >=50s to type (probably closer to 200ms between words)
// https://stackoverflow.com/questions/22505698/what-is-a-typical-keypress-duration
var wg sync.WaitGroup
wg.Add(1)
go func() {
time.Sleep(50 * time.Millisecond)
const msg = "Mailing auth code..."
for _, r := range msg {
time.Sleep(20 * time.Millisecond)
fmt.Fprintf(bufConn, string(r))
}
time.Sleep(50 * time.Millisecond)
wg.Done()
}()
if "" != config.Mailer.ApiKey {
wg.Add(1)
go func() {
code, err = sendAuthCode(config.Mailer, strings.TrimSpace(email))
wg.Done()
}()
} else {
code, err = genAuthCode()
}
wg.Wait()
if nil != err {
// TODO handle better
// (not sure why a random number would fail,
// but on a machine without internet the calls
// to mailgun APIs would fail)
panic(err)
}
// so I don't have to actually go check my email
fmt.Fprintf(os.Stdout, "\n== AUTHORIZATION ==\n[cheat code for %s]: %s\n", email, code)
time.Sleep(150 * time.Millisecond)
fmt.Fprintf(bufConn, " done\n")
time.Sleep(150 * time.Millisecond)
fmt.Fprintf(bufConn, "Auth Code: ")
continue
}
if code != strings.TrimSpace(string(buf[:count])) {
fmt.Fprintf(bufConn, "Incorrect Code\nAuth Code: ")
} else {
authn = true
time.Sleep(150 * time.Millisecond)
fmt.Fprintf(bufConn, "\n")
u := tcpUser{
bufConn: bufConn,
email: email,
userCount: make(chan int, 1),
}
authTcpChat <- u
// prevent data race on len(myRawConns)
// XXX (there can't be a race between these two lines, right?)
count := <-u.userCount
close(u.userCount)
u.userCount = nil
time.Sleep(50 * time.Millisecond)
fmt.Fprintf(bufConn, "\n")
time.Sleep(50 * time.Millisecond)
fmt.Fprintf(bufConn, "Welcome to #general (%d users)!", count)
time.Sleep(50 * time.Millisecond)
fmt.Fprintf(bufConn, "\n")
time.Sleep(50 * time.Millisecond)
// TODO /help /join <room> /users /channels /block <user> /upgrade <http/ws>
//fmt.Fprintf(bufConn, "(TODO `/help' for list of commands)")
time.Sleep(100 * time.Millisecond)
fmt.Fprintf(bufConn, "\n")
// this would be cool, but won't work since other messages will come
// in before the person responds
//fmt.Fprintf(bufConn, "\n%s> ", email)
}
continue
}
//fmt.Fprintf(os.Stdout, "Queing message...\n")
//myRooms["general"] <- myMsg{
myMsgs <- myMsg{
receivedAt: time.Now(),
sender: bufConn,
bytes: buf[0:count],
channel: "general",
email: email,
}
//fmt.Fprintf(bufConn, "> ")
}
}
func handleSorted(conn bufferedConn) {
// Wish List for protocol detection
// * PROXY protocol (and loop)
// * HTTP CONNECT (proxy) (and loop)
// * tls (and loop) https://github.com/polvi/sni
// * http/ws
// * irc
// * fallback to telnet
// At this piont we've already at least one byte via Peek()
// so the first packet is available in the buffer
// Note: Realistically no tls/http/irc client is going to send so few bytes
// (and no router is going to chunk so small)
// that it cannot reasonably detect the protocol in the first packet
// However, typical MTU is 1,500 and HTTP can have a 2k URL
// so expecting to find the "HTTP/1.1" in the Peek is not always reasonable
n := conn.Buffered()
firstMsg, err := conn.Peek(n)
if nil != err {
conn.Close()
return
}
var protocol string
// between A and z
if firstMsg[0] >= 65 && firstMsg[0] <= 122 {
i := bytes.Index(firstMsg, []byte(" /"))
if -1 != i {
protocol = "HTTP"
// very likely HTTP
j := bytes.IndexAny(firstMsg, "\r\n")
if -1 != j {
k := bytes.Index(bytes.ToLower(firstMsg[:j]), []byte("HTTP/1"))
if -1 != k {
// positively HTTP
}
}
}
} else if 0x16 /*22*/ == firstMsg[0] {
// Because I don't always remember off the top of my head what the first byte is
// http://blog.fourthbit.com/2014/12/23/traffic-analysis-of-an-ssl-slash-tls-session
// https://tlseminar.github.io/first-few-milliseconds/
// TODO I want to learn about ALPN
protocol = "TLS"
}
if "" == protocol {
fmt.Fprintf(conn, "\n\nWelcome to Sample Chat! You're not an HTTP client, assuming Telnet.\nYou must authenticate via email to participate\n\nEmail: ")
newTcpChat <- conn
return
} else if "HTTP" != protocol {
defer conn.Close()
fmt.Fprintf(conn, "\n\nNot yet supported. Try HTTP or Telnet\n\n")
return
}
newHttpClient <- conn
/*
firstMsgs <- myMsg{
receivedAt: time.Now(),
sender: conn,
bytes: firstMsg,
channel: "general",
}
// TODO
// * TCP-CHAT
// * HTTP
// * TLS
// Handle all subsequent packets
buf := make([]byte, 1024)
for {
fmt.Fprintf(os.Stdout, "[sortable] Waiting for message...\n")
count, err := conn.Read(buf)
if nil != err {
if io.EOF != err {
fmt.Fprintf(os.Stderr, "Non-EOF socket error: %s\n", err)
}
fmt.Fprintf(os.Stdout, "Ending socket\n")
break
}
// Fun fact: if the buffer's current length (not capacity) is 0
// then the Read returns 0 without error
if 0 == count {
// fmt.Fprintf(os.Stdout, "Weird")
continue
}
//myRooms["general"] <- myMsg{
myMsgs <- myMsg{
receivedAt: time.Now(),
sender: conn,
bytes: buf[0:count],
channel: "general",
}
}
*/
}
func handleConnection(netConn net.Conn) {
ts := time.Now()
fmt.Fprintf(os.Stdout, "[New Connection] (%s) welcome %s\n", ts, netConn.RemoteAddr().String())
m := sync.Mutex{}
virgin := true
// Why don't these work?
//buf := make([]byte, 0, 1024)
//buf := []byte{}
// But this does
bufConn := newBufferedConn(netConn)
//myUnsortedConns[bufConn] = true
go func() {
// Handle First Packet
_, err := bufConn.Peek(1)
//fmsg, err := bufConn.Peek(1)
if nil != err {
panic(err)
}
//fmt.Fprintf(os.Stdout, "[First Byte] %s\n", fmsg)
m.Lock()
if virgin {
virgin = false
newHttpChat <- bufConn
} else {
newTcpChat <- bufConn
}
m.Unlock()
}()
time.Sleep(250 * 1000000)
// If we still haven't received data from the client
// assume that the client must be expecting a welcome from us
m.Lock()
if virgin {
virgin = false
// don't block for this
// let it be handled after the unlock
defer fmt.Fprintf(netConn, "\n\nWelcome to Sample Chat! You appear to be using Telnet.\nYou must authenticate via email to participate\n\nEmail: ")
}
m.Unlock()
}
func sendAuthCode(cnf ConfMailer, to string) (string, error) {
code, err := genAuthCode()
if nil != err {
return "", err
}
// TODO use go text templates with HTML escaping
text := "Your authorization code:\n\n" + code
html := "Your authorization code:<br><br>" + code
// https://stackoverflow.com/questions/24493116/how-to-send-a-post-request-in-go
// https://stackoverflow.com/questions/16673766/basic-http-auth-in-go
client := http.Client{}
form := url.Values{}
form.Add("from", cnf.From)
form.Add("to", to)
form.Add("subject", "Sample Chat Auth Code: "+code)
form.Add("text", text)
form.Add("html", html)
req, err := http.NewRequest("POST", cnf.Url, strings.NewReader(form.Encode()))
if nil != err {
return "", err
}
//req.PostForm = form
req.Header.Add("User-Agent", "golang http.Client - Sample Chat App Authenticator")
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
req.SetBasicAuth("api", cnf.ApiKey)
resp, err := client.Do(req)
if nil != err {
return "", err
}
defer resp.Body.Close()
// Security XXX
// we trust mailgun implicitly and this is just a demo
// hence no DoS check on body size for now
body, err := ioutil.ReadAll(resp.Body)
if nil != err {
return "", err
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 || "{" != string(body[0]) {
fmt.Fprintf(os.Stdout, "[Mailgun] Uh-oh...\n[Maigun] Baby Brent says: %s\n", body)
} else {
fmt.Fprintf(os.Stdout, "[Mailgun] Status: %d", resp.StatusCode)
}
return code, nil
}
type myServer struct {
chans chan bufferedConn
net.Listener
}
func (m *myServer) Accept() (net.Conn, error) {
bufConn := <-m.chans
return bufConn, nil
}
func newMyServer(l net.Listener) *myServer {
return &myServer{make(chan bufferedConn), l}
}
var config Conf
func serveStatic(req *restful.Request, resp *restful.Response) {
actual := path.Join(config.RootPath, req.PathParameter("subpath"))
fmt.Printf("serving %s ... (from %s)\n", actual, req.PathParameter("subpath"))
http.ServeFile(
resp.ResponseWriter,
req.Request,
actual)
}
func serveHello(req *restful.Request, resp *restful.Response) {
fmt.Fprintf(resp, "{\"msg\":\"hello\"}")
}
type authReq struct {
Cid string `json:"cid"`
ChallengedAt time.Time `json:"-"`
Chan chan authReq `json:"-"`
Code string `json:"code"`
CreatedAt time.Time `json:"-"`
DidAuth bool `json:"-"`
Email string `json:"email"`
VerifiedAt time.Time `json:"-"`
Tries int `json:"-"`
}
func requestAuth(req *restful.Request, resp *restful.Response) {
ar := authReq{
CreatedAt: time.Now(),
Tries: 0,
}
err := req.ReadEntity(&ar)
// Looks like restful handles JSON automatically?
/*
err := json.NewDecoder(req.Body).Decode(&ar)
*/
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad json in request body\"} }")
return
}
email := strings.TrimSpace(ar.Email)
emailParts := strings.Split(email, "@")
if 2 != len(emailParts) {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad email address '"+email+"'\"} }")
return
}
var code string
if "" != config.Mailer.ApiKey {
code, err = sendAuthCode(config.Mailer, email)
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error sending auth code via mailgun\" } }")
return
}
}
if "" == code {
code, err = genAuthCode()
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error generating random number (code)\"} }")
return
}
}
fmt.Fprintf(os.Stdout, "\n== AUTHORIZATION ==\n[cheat code for %s]: %s\n", ar.Email, ar.Code)
cid, _ := genAuthCode()
if "" == cid {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error generating random number (cid)\"} }")
}
ar.Cid = cid
ar.DidAuth = false
ar.Email = email
ar.Code = code
newAuthReqs <- ar
fmt.Fprintf(resp, "{ \"success\": true, \"cid\": \""+ar.Cid+"\" }")
}
func issueToken(req *restful.Request, resp *restful.Response) {
ar := authReq{}
cid := req.PathParameter("cid")
if "" == cid {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad cid in request url params\"} }")
return
}
//err := json.NewDecoder(r.Body).Decode(&ar)
err := req.ReadEntity(&ar)
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad json in request body\"} }")
return
}
ar.Cid = cid
ar.Chan = make(chan authReq)
valAuthReqs <- ar
av := <-ar.Chan
close(ar.Chan)
ar.Chan = nil
av.Tries += 1
av.ChallengedAt = time.Now()
// TODO security checks
// * ChallengedAt was at least 1 second ago
// * Tries does not exceed 5
// * CreatedAt is not more than 15 minutes old
// Probably also need to make sure than not more than n emails are sent per y minutes
// Not that this would even matter with the above, just a habit
if 1 != subtle.ConstantTimeCompare([]byte(av.Code), []byte(ar.Code)) {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"invalid authorization code\"} }")
// I'm not sure if this is necessary, but I think it is
// to overwrite the original with the updated
// (these are copies, not pointers, IIRC)
// of course, should use a DB anyway...
newAuthReqs <- av
return
}
av.DidAuth = true
ar.VerifiedAt = time.Now()
newAuthReqs <- av
fmt.Fprintf(resp, "{ \"success\": true, \"token\": \""+ar.Cid+"\" }")
}
func requireToken(req *restful.Request, resp *restful.Response, chain *restful.FilterChain) {
//req.SetAttribute("go", "there")
//req.Attribute("go") // "there"
chain.ProcessFilter(req, resp)
}
func listMsgs(req *restful.Request, resp *restful.Response) {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_NO_IMPL\", \"message\": \"invalid authorization code\"} }")
}
func postMsg(req *restful.Request, resp *restful.Response) {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_NO_IMPL\", \"message\": \"invalid authorization code\"} }")
}
func main() {
flag.Usage = usage
port := flag.Uint("telnet-port", 0, "tcp telnet chat port")
confname := flag.String("conf", "./config.yml", "yaml config file")
flag.Parse()
confstr, err := ioutil.ReadFile(*confname)
fmt.Fprintf(os.Stdout, "-conf=%s\n", *confname)
if nil != err {
fmt.Fprintf(os.Stderr, "%s\nUsing defaults instead\n", err)
confstr = []byte("{\"port\":" + strconv.Itoa(int(*port)) + "}")
}
err = yaml.Unmarshal(confstr, &config)
if nil != err {
config = Conf{}
}
if "" == config.RootPath {
// TODO Embed the public dir at the default
config.RootPath = "./public"
}
myRawConns := make(map[bufferedConn]bool)
myAuthReqs := make(map[string]authReq)
firstMsgs = make(chan myMsg, 128)
//myRooms = make(map[string](chan myMsg))
newConns = make(chan net.Conn, 128)
authTcpChat = make(chan tcpUser, 128)
newAuthReqs = make(chan authReq, 128)
valAuthReqs = make(chan authReq, 128)
delAuthReqs = make(chan authReq, 128)
newTcpChat = make(chan bufferedConn, 128)
newHttpChat = make(chan bufferedConn, 128)
newHttpClient = make(chan bufferedConn, 128)
//myUnsortedConns = make(map[net.Conn]bool)
// TODO dynamically select on channels?
// https://stackoverflow.com/questions/19992334/how-to-listen-to-n-channels-dynamic-select-statement
//myRooms["general"] = make(chan myMsg, 128)
myMsgs = make(chan myMsg, 128)
var addr string
if 0 != int(*port) {
addr = ":" + strconv.Itoa(int(*port))
} else {
addr = ":" + strconv.Itoa(int(config.Port))
}
// https://golang.org/pkg/net/#Conn
sock, err := net.Listen("tcp", addr)
if nil != err {
fmt.Fprintf(os.Stderr, "Couldn't bind to TCP socket %q: %s\n", addr, err)
os.Exit(2)
}
fmt.Println("Listening on", addr)
go func() {
for {
conn, err := sock.Accept()
if err != nil {
// Not sure what kind of error this could be or how it could happen.
// Could a connection abort or end before it's handled?
fmt.Fprintf(os.Stderr, "Error accepting connection:\n%s\n", err)
}
newConns <- conn
}
}()
// Learning by Example
// https://github.com/emicklei/go-restful/blob/master/examples/restful-multi-containers.go
// https://github.com/emicklei/go-restful/blob/master/examples/restful-basic-authentication.go
// https://github.com/emicklei/go-restful/blob/master/examples/restful-serve-static.go
// https://github.com/emicklei/go-restful/blob/master/examples/restful-pre-post-filters.go
container := restful.NewContainer()
wsStatic := new(restful.WebService)
wsStatic.Path("/")
wsStatic.Route(wsStatic.GET("/").To(serveStatic))
wsStatic.Route(wsStatic.GET("/{subpath:*}").To(serveStatic))
container.Add(wsStatic)
cors := restful.CrossOriginResourceSharing{ExposeHeaders: []string{"Authorization"}, CookiesAllowed: false, Container: container}
wsApi := new(restful.WebService)
wsApi.Path("/api").Consumes(restful.MIME_JSON).Produces(restful.MIME_JSON).Filter(cors.Filter)
wsApi.Route(wsApi.GET("/hello").To(serveHello))
wsApi.Route(wsApi.POST("/sessions").To(requestAuth))
wsApi.Route(wsApi.POST("/sessions/{cid}").To(issueToken))
wsApi.Route(wsApi.GET("/rooms/general").Filter(requireToken).To(listMsgs))
wsApi.Route(wsApi.POST("/rooms/general").Filter(requireToken).To(postMsg))
container.Add(wsApi)
server := &http.Server{
Addr: addr,
Handler: container,
}
myHttpServer := newMyServer(sock)
go func() {
server.Serve(myHttpServer)
}()
// Main event loop handling most access to shared data
for {
select {
case conn := <-newConns:
// This is short lived
go handleConnection(conn)
case u := <-authTcpChat:
// allow to receive messages
// (and be counted among the users)
myRawConns[u.bufConn] = true
// is chan chan the right way to handle this?
u.userCount <- len(myRawConns)
myMsgs <- myMsg{
sender: nil,
// TODO fmt.Fprintf()? template?
bytes: []byte("<" + u.email + "> joined #general\n"),
receivedAt: time.Now(),
channel: "general",
email: "system",
}
case ar := <-newAuthReqs:
myAuthReqs[ar.Cid] = ar
case av := <-valAuthReqs:
// TODO In this case it's probably more conventional (and efficient) to
// use struct with a mutex and the authReqs map than a chan chan
av.Chan <- myAuthReqs[av.Cid]
case ar := <-delAuthReqs:
delete(myAuthReqs, ar.Cid)
case bufConn := <-newTcpChat:
go handleRaw(bufConn)
case bufConn := <-delTcpChat:
// we can safely ignore this error
bufConn.Close()
delete(myRawConns, bufConn)
case bufConn := <-newHttpChat:
go handleSorted(bufConn)
//case msg := <- myRooms["general"]:
//delete(myRooms["general"], bufConn)
case bufConn := <-newHttpClient:
// this will be Accept()ed immediately by restful
myHttpServer.chans <- bufConn
case msg := <-myMsgs:
t := msg.receivedAt
tf := "%d-%02d-%02d %02d:%02d:%02d (%s)"
var sender string
if nil != msg.sender {
sender = msg.sender.RemoteAddr().String()
} else {
sender = "system"
}
// I wonder if we could use IP detection to get the client's tz
// ... could probably make time for this in the authentication loop
zone, _ := msg.receivedAt.Zone()
//ts, err := msg.receivedAt.MarshalJSON()
fmt.Fprintf(os.Stdout, tf+" [%s] (%s):\n\t%s",
t.Year(), t.Month(), t.Day(),
t.Hour(), t.Minute(), t.Second(), zone,
sender,
msg.email, msg.bytes)
for conn, _ := range myRawConns {
// Don't echo back to the original client
if msg.sender == conn {
continue
}
// To ask: Why do I have to pass in conn to prevent a data race? Is it garbage collection?
// Don't block the rest of the loop
// TODO maybe use a chan to send to the socket's event loop
go func(conn bufferedConn) {
// Protect against malicious clients to prevent DoS
// https://blog.cloudflare.com/the-complete-guide-to-golang-net-http-timeouts/
timeoutDuration := 5 * time.Second
conn.SetWriteDeadline(time.Now().Add(timeoutDuration))
_, err := fmt.Fprintf(conn, tf+" [%s]: %s",
t.Year(), t.Month(), t.Day(),
t.Hour(), t.Minute(), t.Second(), zone,
msg.email, msg.bytes)
if nil != err {
delTcpChat <- conn
}
}(conn)
}
case msg := <-firstMsgs:
fmt.Fprintf(os.Stdout, "f [First Message]\n")
ts, err := msg.receivedAt.MarshalJSON()
if nil != err {
fmt.Fprintf(os.Stderr, "f [Error] %s\n", err)
}
fmt.Fprintf(os.Stdout, "f [Timestamp] %s\n", ts)
fmt.Fprintf(os.Stdout, "f [Remote] %s\n", msg.sender.RemoteAddr().String())
fmt.Fprintf(os.Stdout, "f [Message] %s\n", msg.bytes)
}
}
}