/
chat.go
473 lines (414 loc) · 13.2 KB
/
chat.go
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package main
import (
"time"
"bufio"
"io"
"io/ioutil"
//"bytes"
"net"
"net/http"
"os"
"sync"
//"crypto/md5"
//"hash"
//"html/template"
"encoding/json"
"fmt"
"log"
"strings"
//"encoding/hex"
"flag"
"runtime"
//"reflect"
)
const serverTimeout int64 = 45
const allowedOnOffDiff int64 = 3
type TimestampedMessage struct {
Type string
Value interface{}
CreatedTime int64
}
type commEntity struct {
id string
recv chan TimestampedMessage
group_id string
status string
onlineSince int64
offlineSince int64
onOffDiff int64
}
type ConcurrentUsersMap struct {
mu sync.RWMutex
m map[string]commEntity
}
func (u ConcurrentUsersMap) Get(comm_id string) commEntity {
u.mu.RLock()
defer u.mu.RUnlock()
return u.m[comm_id]
}
func (u ConcurrentUsersMap) GetUserCommEntities(prefix_id string) (userCommEntities []commEntity) {
prefix_id = prefix_id + "_"
u.mu.RLock()
defer u.mu.RUnlock()
for _, userCommEntity := range u.m {
if strings.Contains(userCommEntity.id, prefix_id) {
userCommEntities = append(userCommEntities, userCommEntity)
}
}
return
}
func (u ConcurrentUsersMap) GetAllGroupUsers(group_id string) (groupCommEntities []commEntity) {
u.mu.RLock()
defer u.mu.RUnlock()
for _, userCommEntity := range u.m {
if userCommEntity.group_id == group_id {
groupCommEntities = append(groupCommEntities, userCommEntity)
}
}
return
}
func (u ConcurrentUsersMap) Set(comm_id string, value commEntity) {
u.mu.Lock()
defer u.mu.Unlock()
u.m[comm_id] = value
}
func (u ConcurrentUsersMap) Contains(comm_id string) (exists bool) {
u.mu.RLock()
defer u.mu.RUnlock()
_, exists = u.m[comm_id]
return exists
}
func NewUsers() ConcurrentUsersMap {
return ConcurrentUsersMap{m: make(map[string]commEntity)}
}
var users = NewUsers()
//var users map[string]commEntity = make(map[string]commEntity)
var numCores = flag.Int("n", runtime.NumCPU(), "number of CPU cores to use")
//var room map[string]Chann = make(map[string]Chann)
func testPage(w http.ResponseWriter, req *http.Request) {
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Content-Type", "text/html; charset=iso-8859-1")
resourceData, err := ioutil.ReadFile("./testPage.html")
if err != nil {
fmt.Printf("###\nError - %s\n###\n", err)
os.Exit(1)
}
io.WriteString(w, string(resourceData))
}
func jquery(w http.ResponseWriter, req *http.Request) {
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Content-Type",
"application/javascript; charset=iso-8859-1")
resourceData, err := ioutil.ReadFile("./jquery.js")
if err != nil {
fmt.Printf("###\nError - %s\n###\n", err)
os.Exit(1)
}
io.WriteString(w, string(resourceData))
}
func cssStyle(w http.ResponseWriter, req *http.Request) {
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Content-Type", "text/css; charset=utf-8")
resourceData, err := ioutil.ReadFile("./style.css")
if err != nil {
fmt.Printf("###\nError - %s\n###\n", err)
os.Exit(1)
}
io.WriteString(w, string(resourceData))
}
func writeMessageUser(comm_id string, message TimestampedMessage) {
recepientUser := users.Get(comm_id)
if userActive(recepientUser) {
recepientUser.recv <- message
}
// else - write to DB ?
}
func getAllOnlineUsers(requestingCommId string, group_id string) {
var message TimestampedMessage
var onlineUsers []string
prefix_clientId := strings.Split(requestingCommId, "_")
prefix_id := prefix_clientId[0] + "_"
exists := users.Contains(requestingCommId)
if exists {
groupCommEntities := users.GetAllGroupUsers(group_id)
for _, cEntity := range groupCommEntities {
if userActive(cEntity) {
if !strings.Contains(cEntity.id, prefix_id) {
onlineUsers = append(onlineUsers, cEntity.id)
}
}
}
message.Value = onlineUsers
message.CreatedTime = (time.Now()).Unix()
message.Type = "allpresence"
writeMessageUser(requestingCommId, message)
}
}
func fetchAllOnlineUsers(w http.ResponseWriter, req *http.Request) {
var message TimestampedMessage
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Content-Type", "application/json; charset=UTF-8")
w.Header().Set("Access-Control-Allow-Origin", "*")
go getAllOnlineUsers(req.FormValue("comm_id"), req.FormValue("group_id"))
message.CreatedTime = (time.Now()).Unix()
message.Value = "success"
message.Type = "success"
marshalData, _ := json.Marshal(message)
jsonResponse := string(marshalData)
io.WriteString(w, jsonResponse)
}
func userActive(cEntity commEntity) (active bool) {
currentUnixTime := (time.Now()).Unix()
active = false
users.mu.Lock()
defer users.mu.Unlock()
if cEntity.status == "active" {
active = true
} else {
onOffdiff := cEntity.onOffDiff - (2 * cEntity.onOffDiff)
currOffDiff := currentUnixTime - cEntity.offlineSince
// when status is 'inactive', onOffDiff should be between 0 & serverTimeout
// Reason: since its inactive, last event is offline.
if 0 <= onOffdiff && onOffdiff <= serverTimeout {
// currOffDiff should be < 3. Reason: two cases -
// 1. conn is closed and client is connecting back(within few seconds gap)
// 2. conn is closed and client is not connecting back at all
// if its connecting back it will definetely connect back in less than 3
if currOffDiff < allowedOnOffDiff {
active = true
}
}
fmt.Printf("Online -- %v %s = %d = %d\n", active, cEntity.id, onOffdiff, currOffDiff)
}
//fmt.Printf("Online status %v '%s'\n", active, cEntity.status)
return
}
func messageActive(createdTime int64) (active bool) {
currentUnixTime := (time.Now()).Unix()
active = false
if currentUnixTime-createdTime < 15 {
active = true
}
return
}
func sendMessage(w http.ResponseWriter, req *http.Request) {
//var err error
var message TimestampedMessage
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Content-Type", "application/javascript")
response := "message sent"
comm_id_prefix := req.FormValue("comm_id")
group_id := req.FormValue("group_id")
message.Value = req.FormValue("msg")
message.CreatedTime = (time.Now()).Unix()
message.Type = "chat"
cEntities := users.GetUserCommEntities(comm_id_prefix)
//fmt.Printf("===== %v \n%T \n%#v =====\n", cEntities, cEntities, cEntities)
for _, cEntity := range cEntities {
if cEntity.group_id == group_id {
writeMessageUser(cEntity.id, message)
}
}
io.WriteString(w, response)
/*if err == nil {
fmt.Printf("Response sent- %s %s\n", req.URL, time.Now())
}*/
}
func openPushChannel(comm_id string, group_id string) chan TimestampedMessage {
var newUser commEntity
var userRecvChannel chan TimestampedMessage
//var tempTime time.Time
currentUnixTime := (time.Now()).Unix()
exists := users.Contains(comm_id)
if exists {
//fmt.Printf("Already joined> User-id:%v \n", comm_id)
// work around for bug http://code.google.com/p/go/issues/detail?id=3117
tempUser := users.Get(comm_id)
tempUser.onlineSince = currentUnixTime
tempUser.onOffDiff = tempUser.onlineSince - tempUser.offlineSince
tempUser.status = "active"
users.Set(comm_id, tempUser)
tempoUser := users.Get(comm_id)
userRecvChannel = tempoUser.recv
if tempUser.onOffDiff > allowedOnOffDiff {
go notifyUserActiveToGroup(comm_id, group_id)
}
} else {
fmt.Printf("New join> User-id:%v \n", comm_id)
newUser.id = comm_id
newUser.recv = make(chan TimestampedMessage, 100)
newUser.onlineSince = currentUnixTime
newUser.offlineSince = currentUnixTime - 3
newUser.onOffDiff = newUser.onlineSince - newUser.offlineSince
newUser.status = "active"
newUser.group_id = group_id
users.Set(newUser.id, newUser)
userRecvChannel = newUser.recv
// notify all users of the group about the new user
go notifyUserActiveToGroup(comm_id, group_id)
}
return userRecvChannel
}
func notifyUserActiveToGroup(comm_id string, group_id string) {
var message TimestampedMessage
var newUser []string = []string{comm_id}
prefix_clientId := strings.Split(comm_id, "_")
prefix_id := prefix_clientId[0] + "_"
groupCommEntities := users.GetAllGroupUsers(group_id)
for _, cEntity := range groupCommEntities {
if !strings.Contains(cEntity.id, prefix_id) {
message.Value = newUser
message.CreatedTime = (time.Now()).Unix()
message.Type = "presence"
writeMessageUser(cEntity.id, message)
}
}
}
func notifyUserOfflineToGroup(comm_id string, group_id string) {
var message TimestampedMessage
var offlineUser []string = []string{comm_id}
prefix_clientId := strings.Split(comm_id, "_")
prefix_id := prefix_clientId[0]
timeout := time.After(3 * time.Second)
select {
case <-timeout:
cUserEntities := users.GetUserCommEntities(prefix_id)
active := false
for _, cUserEntity := range cUserEntities {
if userActive(cUserEntity) {
active = true
break
}
}
//fmt.Printf("@User %s is %v %v\n", prefix_id, active, cUserEntities)
if !active {
groupCommEntities := users.GetAllGroupUsers(group_id)
for _, cEntity := range groupCommEntities {
if cEntity.id != comm_id {
message.Value = offlineUser
message.CreatedTime = (time.Now()).Unix()
message.Type = "offpresence"
writeMessageUser(cEntity.id, message)
}
}
}
}
}
func getMessage(recv chan TimestampedMessage, hjConnChan chan TimestampedMessage) (msg TimestampedMessage) {
timeout := time.After(45 * time.Second)
select {
case newMessage := <-recv:
msg = newMessage
case <-timeout:
msg.CreatedTime = (time.Now()).Unix()
msg.Value = "serverTimeout"
msg.Type = "serverTimeout"
case <-hjConnChan:
msg.CreatedTime = (time.Now()).Unix()
msg.Value = "clientClose"
msg.Type = "clientClose"
}
return msg
}
func setCommEntityInactive(comm_id string) {
cEntity := users.Get(comm_id)
cEntity.status = "inactive"
cEntity.offlineSince = (time.Now()).Unix()
cEntity.onOffDiff = cEntity.onlineSince - cEntity.offlineSince
users.Set(comm_id, cEntity)
}
func subscribeMessage(w http.ResponseWriter, req *http.Request) {
var hjConnChan chan TimestampedMessage = make(chan TimestampedMessage, 1)
recv := openPushChannel(req.FormValue("comm_id"), req.FormValue("group_id"))
hjConn, bufrw := httpHijack(w)
defer hjConn.Close()
go notifyClientDisconnect(bufrw, hjConnChan, req.FormValue("comm_id"), req.FormValue("group_id"), req.FormValue("join_time"))
newMessage := getMessage(recv, hjConnChan)
buildHTTPResponse(bufrw)
if newMessage.Type == "serverTimeout" {
fmt.Printf("Server timed out> User-id:%s %s \n",
req.FormValue("comm_id"),
req.FormValue("join_time"))
} else if newMessage.Type == "clientClose" {
fmt.Printf("Client closed conn> User-id:%s %s \n",
req.FormValue("comm_id"),
req.FormValue("join_time"))
} else if newMessage.Type == "presence" {
fmt.Printf("Presence Message sent to> User-id:%s %s %s\n", req.FormValue("comm_id"),
req.FormValue("join_time"), newMessage.Value)
} else if newMessage.Type == "chat" {
fmt.Printf("Message sent to> User-id:%s %s %s\n", req.FormValue("comm_id"),
req.FormValue("join_time"), newMessage.Value)
}
if messageActive(newMessage.CreatedTime) {
marshalData, _ := json.Marshal(newMessage)
jsonResponse := string(marshalData)
fmt.Printf("\tjson: %s \n", jsonResponse)
// write body
bufrw.WriteString(jsonResponse + "\r\n")
bufrw.Flush()
}
}
func buildHTTPResponse(bufrw *bufio.ReadWriter) {
var newHeader http.Header = make(http.Header)
newHeader.Add("Access-Control-Allow-Origin", "*")
newHeader.Add("Content-Type", "application/json; charset=UTF-8")
newHeader.Add("Cache-Control", "no-cache")
newHeader.Add("X-AppServer", "GoAPP")
// write status line
bufrw.WriteString("HTTP/1.1 200 OK" + "\r\n")
// write headers
_ = newHeader.Write(bufrw)
// write a black line
bufrw.WriteString("\n")
}
func notifyClientDisconnect(bufrw *bufio.ReadWriter, hjConnChan chan TimestampedMessage, comm_id string, group_id string, join_time string) {
var message TimestampedMessage
// listen if client has closed the connection
bs, err := bufrw.Reader.Peek(1)
if len(bs) == 0 && err != nil {
//fmt.Printf("error: %v %T %#v\n", err, err, err)
if _, ok := err.(*net.OpError); ok {
fmt.Printf("Server closed conn> User-id:%s %s\n", comm_id, join_time)
} else {
//fmt.Printf("client side hjConn close\n")
message.CreatedTime = (time.Now()).Unix()
message.Value = "clientClose"
message.Type = "clientClose"
hjConnChan <- message
}
setCommEntityInactive(comm_id)
notifyUserOfflineToGroup(comm_id, group_id)
}
}
func httpHijack(w http.ResponseWriter) (net.Conn, *bufio.ReadWriter) {
hj, ok := w.(http.Hijacker)
if !ok {
http.Error(w, "webserver doesn't support hijacking",
http.StatusInternalServerError)
}
// hijack http connection to tcp
hjConn, bufrw, err := hj.Hijack()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
return hjConn, bufrw
}
func main() {
// make sure app uses all cores
flag.Parse()
runtime.GOMAXPROCS(*numCores)
fmt.Printf("\nPresence server running at "+
"http://127.0.0.1:8088 on %d CPU cores\n", *numCores)
http.HandleFunc("/", testPage)
http.HandleFunc("/jquery.js", jquery)
http.HandleFunc("/style.css", cssStyle)
http.HandleFunc("/subscribe/message/", subscribeMessage)
http.HandleFunc("/send/message/", sendMessage)
http.HandleFunc("/get/onlineUsers/", fetchAllOnlineUsers)
err := http.ListenAndServe("127.0.0.1:8088", nil)
if err != nil {
log.Fatal("In main(): ", err)
}
}