An example chat server in golang.
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package main
// TODO learn more 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 // See https://github.com/polvi/sni/blob/master/sni.go#L135
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
Message string `json:"message"`
ReceivedAt time.Time `json:"received_at"`
Channel string `json:"channel"`
User string `json:"user"`
}
type JsonMsg struct {
Messages []myMsg `json:"messages"`
}
//var firstMsgs chan myMsg
//var myRooms map[string](chan myMsg)
var msgHistory []myMsg
var broadcastMsg chan myMsg
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== TELNET 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{
broadcastMsg <- myMsg{
ReceivedAt: time.Now(),
sender: bufConn,
Message: string(buf[0:count]),
Channel: "general",
User: 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,
Message: 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{
broadcastMsg <- myMsg{
ReceivedAt: time.Now(),
sender: conn,
Message: string(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
bufConn := newBufferedConn(netConn)
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 (http is also available on this port)."+
"\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\"}")
}
// TODO I probably should just make the non-exportable properties private/lowercase
type authReq struct {
Cid string `json:"cid"`
ChallengedAt time.Time `json:"-"`
Chan chan authReq `json:"-"`
Otp string `json:"otp"`
CreatedAt time.Time `json:"-"`
DidAuth bool `json:"-"`
Subject string `json:"sub"` // Subject as in 'sub' as per OIDC
VerifiedAt time.Time `json:"-"`
Tries int `json:"-"`
}
func requestAuth(req *restful.Request, resp *restful.Response) {
ar := authReq{
CreatedAt: time.Now(),
DidAuth: false,
Tries: 0,
}
// Not sure why go restful finds it easier to do ReadEntity() than the "normal" way...
// err := json.NewDecoder(req.Body).Decode(&ar)
err := req.ReadEntity(&ar)
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad json in request body\"} }")
return
}
email := strings.TrimSpace(ar.Subject)
emailParts := strings.Split(email, "@")
// TODO better pre-mailer validation (whitelist characters or use lib)
if 2 != len(emailParts) {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad email address '"+email+"'\"} }")
return
}
ar.Subject = email
var otp string
if "" != config.Mailer.ApiKey {
otp, err = sendAuthCode(config.Mailer, ar.Subject)
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error sending auth code via mailgun\" } }")
return
}
}
if "" == otp {
otp, err = genAuthCode()
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error generating random number (code)\"} }")
return
}
}
ar.Otp = otp
// Cheat code in case you didn't set up mailgun keys
fmt.Fprintf(os.Stdout, "\n== HTTP AUTHORIZATION ==\n[cheat code for %s]: %s\n", ar.Subject, ar.Otp)
cid, _ := genAuthCode()
if "" == cid {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"error generating random number (cid)\"} }")
}
ar.Cid = cid
newAuthReqs <- ar
// Not sure why this works... technically there needs to be some sort of "end"
// maybe it just figures that if I've returned
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
// TODO use a pointer instead?
if "" == av.Otp {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"invalid request: empty authorization challenge\"} }")
return
}
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 if the above were implemented, just a habit
if 1 != subtle.ConstantTimeCompare([]byte(av.Otp), []byte(ar.Otp)) {
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)
// and it seems like this is how I might write to a DB anyway
newAuthReqs <- av
return
}
av.DidAuth = true
ar.VerifiedAt = time.Now()
newAuthReqs <- av
// TODO I would use a JWT, but I need to wrap up this project
fmt.Fprintf(resp, "{ \"success\": true, \"token\": \""+ar.Cid+"\" }")
}
func requireToken(req *restful.Request, resp *restful.Response, chain *restful.FilterChain) {
ar := authReq{}
auth := req.HeaderParameter("Authorization")
if "" == auth {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"missing Authorization header\"} }")
return
}
authParts := strings.Split(auth, " ")
if "bearer" != strings.ToLower(authParts[0]) || "" == authParts[1] {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"expected 'Authorization: Bearer <Token>'\"} }")
return
}
ar.Cid = authParts[1]
ar.Chan = make(chan authReq)
valAuthReqs <- ar
av := <-ar.Chan
close(ar.Chan)
ar.Chan = nil
// TODO use a pointer instead?
if "" == av.Cid {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"invalid token: no session found\"} }")
return
}
// I prefer testing for "if not good" to "if bad"
// (much safer in the dynamic world I come from)
if true != av.DidAuth {
fmt.Fprintf(resp, "{ \"error\": { \"message\": \"bad session'\"} }")
return
}
req.SetAttribute("user", av.Subject)
chain.ProcessFilter(req, resp)
}
func listMsgs(req *restful.Request, resp *restful.Response) {
// TODO support ?since=<ISO_TS>
// Also, data race? the list could be added to while this is iterating?
// For now we'll just let the client sort the list
resp.WriteEntity(&JsonMsg{
Messages: msgHistory,
})
}
func postMsg(req *restful.Request, resp *restful.Response) {
user, ok := req.Attribute("user").(string)
if !ok {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_SANITY\", \"message\": \"SANITY FAIL user was not set, nor session error sent\"} }")
return
}
if "" == user {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_SESSION\", \"message\": \"invalid session\"} }")
return
}
msg := myMsg{}
err := req.ReadEntity(&msg)
if nil != err {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_FORMAT\", \"message\": \"invalid json POST\"} }")
return
}
msg.sender = nil
msg.ReceivedAt = time.Now()
msg.User = user
if "" == msg.Channel {
msg.Channel = "general"
}
if "" == msg.Message {
fmt.Fprintf(resp, "{ \"error\": { \"code\": \"E_FORMAT\", \"message\": \"please specify a 'message'\"} }")
return
}
broadcastMsg <- msg
fmt.Fprintf(resp, "{ \"success\": true }")
}
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"
}
// The magical sorting hat
newConns = make(chan net.Conn, 128)
// TCP & Authentication
myRawConns := make(map[bufferedConn]bool)
newTcpChat = make(chan bufferedConn, 128)
authTcpChat = make(chan tcpUser, 128)
// HTTP & Authentication
myAuthReqs := make(map[string]authReq)
newAuthReqs = make(chan authReq, 128)
valAuthReqs = make(chan authReq, 128)
delAuthReqs = make(chan authReq, 128)
newHttpChat = make(chan bufferedConn, 128)
newHttpClient = make(chan bufferedConn, 128)
// cruft to delete
//myRooms = make(map[string](chan myMsg))
//firstMsgs = make(chan myMsg, 128)
//myRooms["general"] = make(chan myMsg, 128)
// Note: I had considered dynamically select on channels for rooms.
// https://stackoverflow.com/questions/19992334/how-to-listen-to-n-channels-dynamic-select-statement
// I don't think that's actually the best approach, but I just wanted to save the link
broadcastMsg = make(chan myMsg, 128)
// Poor-Man's container/ring (circular buffer)
msgHistory = make([]myMsg, 128)
msgIndex := 0
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)
broadcastMsg <- myMsg{
sender: nil,
// TODO fmt.Fprintf()? template?
Message: "<" + u.email + "> joined #general\n",
ReceivedAt: time.Now(),
Channel: "general",
User: "system",
}
case ar := <-newAuthReqs:
myAuthReqs[ar.Cid] = ar
case ar := <-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, ok := myAuthReqs[ar.Cid]
//ar.Chan <- nil // TODO
if ok {
ar.Chan <- av
} else {
ar.Chan <- authReq{}
}
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
// NOTE: we don't store these HTTP connections for broadcast
// as we manage the session by HTTP Auth Bearer rather than TCP
myHttpServer.chans <- bufConn
case msg := <-broadcastMsg:
msgHistory[msgIndex] = msg
msgIndex += 1
msgIndex %= len(msgHistory)
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"
}
// Tangential thought:
// 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()
// TODO put logging here
//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.User, msg.Message)
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.User, msg.Message)
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.Message)
*/
}
}
}