email auth works

chatserver.go

@@ -5,25 +5,32 @@ package main
 
 import (
   "bufio"
+  "crypto/rand"
+  "encoding/base64"
   "flag"
   "fmt"
   "io"
   "io/ioutil"
   "net"
+  "net/http"
+  "net/url"
   "os"
   "strconv"
+  "strings"
   "sync"
   "time"
 
   "gopkg.in/yaml.v2"
 )
 
-type Conf struct {
+type ConfMailer struct {
-  Port uint `yaml:"port,omitempty"`
+  Url string `yaml:"url,omitempty"`
-  Mailer struct {
   ApiKey string `yaml:"api_key,omitempty"`
   From string `yaml:"from,omitempty"`
-  }
+}
+type Conf struct {
+  Port uint `yaml:"port,omitempty"`
+  Mailer ConfMailer
 }
 
 type bufferedConn struct {
@@ -55,10 +62,12 @@ type myMsg struct {
   sender net.Conn
   bytes []byte
   receivedAt time.Time
+  channel string
 }
 
 var firstMsgs chan myMsg
-var myMsgs chan myMsg
+var myChans map[string](chan myMsg)
+//var myMsgs chan myMsg
 var myUnsortedConns map[net.Conn]bool
 var myRawConns map[net.Conn]bool
 var newConns chan net.Conn
@@ -71,6 +80,18 @@ func usage() {
   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(conn bufferedConn) {
   // TODO
   // What happens if this is being read from range
@@ -78,29 +99,72 @@ func handleRaw(conn bufferedConn) {
   // 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
-  buf := make([]byte, 1024)
+  buffer := make([]byte, 1024)
   for {
     fmt.Fprintf(os.Stdout, "[raw] Waiting for message...\n");
-    count, err := conn.Read(buf)
+    count, err := conn.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")
+
+      // TODO put this in a channel to prevent data races
+      conn.Close();
+      delete(myRawConns, conn)
       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 {
+        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(conn, "Email: ")
           continue
         }
+        fmt.Fprintf(os.Stdout, "email: '%v'\n", []byte(email))
+        code, err = sendAuthCode(config.Mailer, strings.TrimSpace(email))
+        if nil != err {
+          // TODO handle better
+          panic(err)
+        }
+        fmt.Fprintf(conn, "Auth Code: ")
+        continue
+      }
+
+      if code != strings.TrimSpace(string(buf[:count])) {
+        fmt.Fprintf(conn, "Incorrect Code\nAuth Code: ")
+      } else {
+        authn = true
+        fmt.Fprintf(conn, "Welcome to #general! (TODO `/help' for list of commands)\n")
+        // TODO number of users
+        //fmt.Fprintf(conn, "Welcome to #general! TODO `/list' to see channels. `/join chname' to switch.\n")
+      }
+      continue
+    }
+
     fmt.Fprintf(os.Stdout, "Queing message...\n");
-    myMsgs <- myMsg{
+    myChans["general"] <- myMsg{
       receivedAt: time.Now(),
       sender: conn,
       bytes: buf[0:count],
+      channel: "general",
     }
   }
 }
@@ -117,6 +181,7 @@ func handleSorted(conn bufferedConn) {
     receivedAt: time.Now(),
     sender: conn,
     bytes: firstMsg,
+    channel: "general",
   }
 
   // TODO
@@ -142,28 +207,29 @@ func handleSorted(conn bufferedConn) {
       // fmt.Fprintf(os.Stdout, "Weird")
       continue
     }
-    myMsgs <- myMsg{
+    myChans["general"] <- myMsg{
       receivedAt: time.Now(),
       sender: conn,
       bytes: buf[0:count],
+      channel: "general",
     }
   }
 }
 
 // TODO https://github.com/polvi/sni
-func handleConnection(conn net.Conn) {
+func handleConnection(netConn net.Conn) {
   fmt.Fprintf(os.Stdout, "Accepting socket\n")
 
   m := sync.Mutex{}
   virgin := true
-  myUnsortedConns[conn] = true
 
   // Why don't these work?
   //buf := make([]byte, 0, 1024)
   //buf := []byte{}
   // But this does
 
-	bufConn := newBufferedConn(conn)
+	bufConn := newBufferedConn(netConn)
+  myUnsortedConns[bufConn] = true
   go func() {
     // Handle First Packet
     fmsg, err := bufConn.Peek(1)
@@ -177,6 +243,8 @@ func handleConnection(conn net.Conn) {
       virgin = false
       go handleSorted(bufConn)
     } else {
+      // TODO probably needs to go into a channel
+      myRawConns[bufConn] = true
       go handleRaw(bufConn)
     }
     m.Unlock();
@@ -188,22 +256,65 @@ func handleConnection(conn net.Conn) {
   m.Lock()
   if virgin {
     virgin = false
-    // TODO probably needs to go into a channel
-    myRawConns[conn] = true
     // don't block for this
     // let it be handled after the unlock
-    defer fmt.Fprintf(conn, "Welcome! This is an open relay chat server. There is no security yet.\n")
+    defer fmt.Fprintf(netConn, "Welcome to Sample Chat! You appear to be using Telnet.\nYou must authenticate via email to participate\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()
+  body, err := ioutil.ReadAll(resp.Body)
+  if nil != err {
+    return "", err
+  }
+  fmt.Fprintf(os.Stdout, "Here's what Mailgun had to say about the event: %s\n", body)
+
+  return code, nil
+}
+
+var config Conf
 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()
 
-  var config Conf
   confstr, err := ioutil.ReadFile(*confname)
   fmt.Fprintf(os.Stdout, "-conf=%s\n", *confname)
   if nil != err {
@@ -216,11 +327,16 @@ func main() {
   }
 
   firstMsgs = make(chan myMsg, 128)
-  myMsgs = make(chan myMsg, 128)
+  //myMsgs = make(chan myMsg, 128)
+  myChans = make(map[string](chan myMsg))
   newConns = make(chan net.Conn, 128)
   myRawConns = make(map[net.Conn]bool)
   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
+  myChans["general"] = make(chan myMsg, 128)
+
   var addr string
   if 0 != int(*port) {
     addr = ":" + strconv.Itoa(int(*port))
@@ -254,7 +370,7 @@ func main() {
       ts := time.Now()
       fmt.Fprintf(os.Stdout, "[Handle New Connection] [Timestamp] %s\n", ts)
       go handleConnection(conn)
-    case msg := <- myMsgs:
+    case msg := <- myChans["general"]:
       ts, err := msg.receivedAt.MarshalJSON()
       if nil != err {
         fmt.Fprintf(os.Stderr, "[Error] %s\n", err)