add listusers and replay subcommand

README.md

@@ -7,7 +7,7 @@ This program allows you to use terminal in the browser. Simply run the program a
 
 2. WiTTY allows users to **easily record, replay, and share console sessions** with just a few clicks. This make it a breeze to answer course-related questions, espeically with the source code. Instead of wall of text to describe their questions, students can just send a recorded session. 
 
-   This repository contains a recorded session in the ```assets/extra``` directory ([M1NXZvHdvA8vSCKp_61e5d60f.rec](extra/M1NXZvHdvA8vSCKp_61e5d60f.rec)) that shows me upgrading pihole. Just put the file under the ```records``` directory, run the server, you should find the recording in the ```Recorded Session``` tab. 
+   This repository contains a recorded session in the ```assets/extra``` directory ([M1NXZvHdvA8vSCKp_61e5d60f.scr](extra/M1NXZvHdvA8vSCKp_61e5d60f.scr)) that shows me upgrading pihole. Just put the file under the ```records``` directory, run the server, you should find the recording in the ```Recorded Session``` tab. 
 
 3. More features are planned, suggestions are welcome.  
 
@@ -80,4 +80,8 @@ Most icons were provided by [fontawesome](https://fontawesome.com/) under this [
 
    ```https://<witty_server_ip>:8080```
 
+8. You can also replay the recorded sessions with witty
+
+   ```./witty replay -w 500 records/<recorded file>.scr```
+
 The program has been tested on Linux, WSL2, Raspberry Pi 3B (Debian), and MacOSX using Google Chrome, Firefox, and Safari.

main.go

@@ -6,19 +6,13 @@ import (
 	"log"
 	"os"
 
+	"github.com/syssecfsu/witty/term_conn"
 	"github.com/syssecfsu/witty/web"
 )
 
 func main() {
-	fp, err := os.OpenFile("witty.log", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
-
-	if err == nil {
-		defer fp.Close()
-		log.SetOutput(fp)
-	}
-
 	if len(os.Args) < 2 {
-		fmt.Println("witty (adduser|deluser|run)")
+		fmt.Println("witty (adduser|deluser|replay|run)")
 		return
 	}
 
@@ -27,6 +21,11 @@ func main() {
 	runCmd.BoolVar(&naked, "n", false, "Run WiTTY without user authentication")
 	runCmd.BoolVar(&naked, "naked", false, "Run WiTTY without user authentication")
 
+	var wait uint
+	replayCmd := flag.NewFlagSet("replay", flag.ExitOnError)
+	replayCmd.UintVar(&wait, "w", 2000, "Max wait time between outputs")
+	replayCmd.UintVar(&wait, "wait", 2000, "Max wait time between outputs")
+
 	switch os.Args[1] {
 	case "adduser":
 		if len(os.Args) != 3 {
@@ -42,7 +41,27 @@ func main() {
 		}
 		web.DelUser(os.Args[2])
 
+	case "listusers":
+		web.ListUsers()
+
+	case "replay":
+		replayCmd.Parse(os.Args[2:])
+
+		if len(replayCmd.Args()) != 1 {
+			fmt.Println("witty replay <recorded>")
+			return
+		}
+
+		term_conn.Replay(replayCmd.Arg(0), wait)
+
 	case "run":
+		fp, err := os.OpenFile("witty.log", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+
+		if err == nil {
+			defer fp.Close()
+			log.SetOutput(fp)
+		}
+
 		runCmd.Parse(os.Args[2:])
 
 		var cmdToExec []string
@@ -57,7 +76,7 @@ func main() {
 		web.StartWeb(fp, cmdToExec, naked)
 
 	default:
-		fmt.Println("witty (adduser|deluser|run)")
+		fmt.Println("witty (adduser|deluser|replay|run)")
 		return
 	}
 

term_conn/replay.go

@@ -0,0 +1,71 @@
+package term_conn
+
+import (
+	"encoding/json"
+	"io"
+	"log"
+	"os"
+	"time"
+
+	"golang.org/x/term"
+)
+
+type writeRecord struct {
+	Dur  time.Duration `json:"Duration"`
+	Data []byte        `json:"Data"`
+}
+
+func Replay(fname string, wait uint) {
+	fp, err := os.Open(fname)
+
+	if err != nil {
+		log.Fatalln("Failed to open record file", err)
+	}
+
+	screen := struct {
+		io.Reader
+		io.Writer
+	}{os.Stdin, os.Stdout}
+
+	t := term.NewTerminal(screen, "$")
+
+	if t == nil {
+		log.Fatalln("Failed to create terminal")
+	}
+
+	w, h, _ := term.GetSize(int(os.Stdout.Fd()))
+
+	if (w != 120) || (h != 36) {
+		log.Println("Set terminal window to 120x36 before continue")
+	}
+
+	decoder := json.NewDecoder(fp)
+
+	if decoder == nil {
+		log.Fatalln("Failed to create JSON decoder")
+	}
+
+	// To work with javascript decoder, we organize the file as
+	// an array of writeRecord. golang decode instead decode
+	// as individual record. Call decoder.Token to skip opening [
+	t.Write([]byte("\n\n---beginning of replay---\n\n"))
+
+	decoder.Token()
+	for decoder.More() {
+		var record writeRecord
+
+		if err := decoder.Decode(&record); err != nil {
+			log.Println("Failed to decode record", err)
+			continue
+		}
+
+		if record.Dur > time.Duration(wait)*time.Millisecond {
+			record.Dur = time.Duration(wait) * time.Millisecond
+		}
+
+		time.Sleep(record.Dur)
+		t.Write(record.Data)
+	}
+
+	t.Write([]byte("\n\n---end of replay---\n\n"))
+}

web/user.go

@@ -5,6 +5,7 @@ import (
 	"crypto/sha256"
 	"encoding/json"
 	"fmt"
+	"log"
 	"os"
 
 	"github.com/dchest/uniuri"
@@ -54,7 +55,7 @@ func addUser(username []byte, passwd []byte) {
 
 	output, err := json.Marshal(users)
 	if err != nil {
-		fmt.Println("Failed to marshal passwords", err)
+		log.Println("Failed to marshal passwords", err)
 		return
 	}
 
@@ -66,7 +67,7 @@ func AddUser(username string) {
 	passwd, err := term.ReadPassword(int(os.Stdin.Fd()))
 
 	if err != nil {
-		fmt.Println("Failed to read password", err)
+		log.Println("Failed to read password", err)
 		return
 	}
 
@@ -74,7 +75,7 @@ func AddUser(username string) {
 	passwd2, err := term.ReadPassword(int(os.Stdin.Fd()))
 
 	if err != nil {
-		fmt.Println("Failed to read password", err)
+		log.Println("Failed to read password", err)
 		return
 	}
 
@@ -93,14 +94,14 @@ func DelUser(username string) {
 	exist := false
 	file, err := os.ReadFile(userFileName)
 	if err != nil {
-		fmt.Println("Failed to read users file", err)
+		log.Println("Failed to read users file", err)
 		return
 	}
 
 	err = json.Unmarshal(file, &users)
 
 	if err != nil {
-		fmt.Println("Failed to parse json format", err)
+		log.Println("Failed to parse json format", err)
 		return
 	}
 	// update the existing user if it exists
@@ -115,7 +116,7 @@ func DelUser(username string) {
 	if exist {
 		output, err := json.Marshal(users)
 		if err != nil {
-			fmt.Println("Failed to marshal passwords", err)
+			log.Println("Failed to marshal passwords", err)
 			return
 		}
 
@@ -123,20 +124,43 @@ func DelUser(username string) {
 	}
 }
 
+func ListUsers() {
+	var users []UserRecord
+	var err error
+
+	file, err := os.ReadFile(userFileName)
+	if err != nil {
+		log.Println("Failed to read users file", err)
+		return
+	}
+
+	err = json.Unmarshal(file, &users)
+
+	if err != nil {
+		log.Println("Failed to parse json format", err)
+		return
+	}
+	// update the existing user if it exists
+	fmt.Println("Users of the system:")
+	for _, u := range users {
+		fmt.Println("   ", string(u.User))
+	}
+}
+
 func ValidateUser(username []byte, passwd []byte) bool {
 	var users []UserRecord
 	var err error
 
 	file, err := os.ReadFile(userFileName)
 	if err != nil {
-		fmt.Println("Failed to read users file", err)
+		log.Println("Failed to read users file", err)
 		return false
 	}
 
 	err = json.Unmarshal(file, &users)
 
 	if err != nil {
-		fmt.Println("Failed to parse json format", err)
+		log.Println("Failed to parse json format", err)
 		return false
 	}