Make telnet output configurable

docs/ghostream.example.yml

@@ -68,6 +68,23 @@ srt:
   # Max number of active SRT connections
   #maxClients: 64
 
+## Telnet server ##
+# The telnet server receive the stream and emit the stream as ASCII-art.
+telnet:
+  # By default, this easter egg is disabled.
+  # You must enable it to use it.
+  #enable: false
+
+  #listenAddress: :4242
+
+  # Size is in characters. It is recommended to keep a 16x9 format.
+  #width: 80
+  #height: 45
+
+  # Time in milliseconds that we should sleep between two images. By default, 20 FPS. Displaying text takes time...
+  #delay: 50
+
+
 ## Web server ##
 # The web server serves a WebRTC player.
 web:

internal/config/config.go

@@ -3,6 +3,7 @@ package config
 
 import (
 	"bytes"
+	"gitlab.crans.org/nounous/ghostream/stream/telnet"
 	"log"
 	"net"
 	"strings"
@@ -25,6 +26,7 @@ type Config struct {
 	Forwarding forwarding.Options
 	Monitoring monitoring.Options
 	Srt        srt.Options
+	Telnet     telnet.Options
 	Web        web.Options
 	WebRTC     webrtc.Options
 }
@@ -56,6 +58,13 @@ func New() *Config {
 			ListenAddress: ":9710",
 			MaxClients:    64,
 		},
+		Telnet: telnet.Options{
+			Enabled:       false,
+			ListenAddress: ":4242",
+			Width:         80,
+			Height:        45,
+			Delay:         50,
+		},
 		Web: web.Options{
 			Enabled:                     true,
 			Favicon:                     "/static/img/favicon.svg",

main.go

@@ -5,6 +5,7 @@
 package main
 
 import (
+	"gitlab.crans.org/nounous/ghostream/stream/telnet"
 	"log"
 
 	"gitlab.crans.org/nounous/ghostream/auth"
@@ -50,6 +51,7 @@ func main() {
 	go forwarding.Serve(forwardingChannel, cfg.Forwarding)
 	go monitoring.Serve(&cfg.Monitoring)
 	go srt.Serve(&cfg.Srt, authBackend, forwardingChannel, webrtcChannel)
+	go telnet.Serve(&cfg.Telnet)
 	go web.Serve(remoteSdpChan, localSdpChan, &cfg.Web)
 	go webrtc.Serve(remoteSdpChan, localSdpChan, webrtcChannel, &cfg.WebRTC)
 

stream/telnet/telnet.go

@@ -8,20 +8,34 @@ import (
 	"time"
 )
 
-func asciiChar(pixel byte) string {
+var (
-	asciiChars := []string{"@", "#", "$", "%", "?", "*", "+", ";", ":", ",", "."}
+	Cfg            *Options
-	return asciiChars[pixel/25]
+	currentMessage *string
+)
+
+// Options holds telnet package configuration
+type Options struct {
+	Enabled       bool
+	ListenAddress string
+	Width         int
+	Height        int
+	Delay         int
 }
 
-// ServeAsciiArt starts a telnet server that send all packets as ASCII Art
+func Serve(config *Options) {
-func ServeAsciiArt(reader io.Reader) {
+	Cfg = config
-	listener, err := net.Listen("tcp", ":4242")
+
-	if err != nil {
+	if !Cfg.Enabled {
-		log.Printf("Error while listening to the port 4242: %s", err)
 		return
 	}
 
-	currentMessage := ""
+	listener, err := net.Listen("tcp", Cfg.ListenAddress)
+	if err != nil {
+		log.Printf("Error while listening to the address %s: %s", Cfg.ListenAddress, err)
+		return
+	}
+
+	currentMessage = new(string)
 
 	go func() {
 		for {
@@ -32,7 +46,7 @@ func ServeAsciiArt(reader io.Reader) {
 			}
 			go func(s net.Conn) {
 				for {
-					n, err := s.Write([]byte(currentMessage))
+					n, err := s.Write([]byte(*currentMessage))
 					if err != nil {
 						log.Printf("Error while sending TCP data: %s", err)
 						_ = s.Close()
@@ -42,13 +56,28 @@ func ServeAsciiArt(reader io.Reader) {
 						_ = s.Close()
 						break
 					}
-					time.Sleep(50 * time.Millisecond)
+					time.Sleep(time.Duration(Cfg.Delay) * time.Millisecond)
 				}
 			}(s)
 		}
 	}()
 
-	buff := make([]byte, 2048)
+	log.Println("Telnet server initialized")
+}
+
+func asciiChar(pixel byte) string {
+	asciiChars := []string{"@", "#", "$", "%", "?", "*", "+", ";", ":", ",", ".", " "}
+	return asciiChars[(255-pixel)/23]
+}
+
+// ServeAsciiArt starts a telnet server that send all packets as ASCII Art
+func ServeAsciiArt(reader io.ReadCloser) {
+	if !Cfg.Enabled {
+		_ = reader.Close()
+		return
+	}
+
+	buff := make([]byte, Cfg.Width*Cfg.Height)
 	header := "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"
 	for {
 		n, _ := reader.Read(buff)
@@ -56,13 +85,13 @@ func ServeAsciiArt(reader io.Reader) {
 			break
 		}
 		imageStr := ""
-		for j := 0; j < 18; j++ {
+		for j := 0; j < Cfg.Height; j++ {
-			for i := 0; i < 32; i++ {
+			for i := 0; i < Cfg.Width; i++ {
-				pixel := buff[32*j+i]
+				pixel := buff[Cfg.Width*j+i]
 				imageStr += asciiChar(pixel) + asciiChar(pixel)
 			}
 			imageStr += "\n"
 		}
-		currentMessage = header + imageStr
+		*currentMessage = header + imageStr
 	}
 }

stream/webrtc/ingest.go

@@ -3,6 +3,7 @@ package webrtc
 
 import (
 	"bufio"
+	"fmt"
 	"gitlab.crans.org/nounous/ghostream/stream/telnet"
 	"io"
 	"log"
@@ -53,7 +54,7 @@ func ingestFrom(inputChannel chan srt.Packet) {
 				"-f", "rtp", "rtp://127.0.0.1:5004",
 				"-vn", "-acodec", "libopus", "-cpu-used", "5", "-deadline", "1", "-qmin", "10", "-qmax", "42", "-error-resilient", "1", "-auto-alt-ref", "1",
 				"-f", "rtp", "rtp://127.0.0.1:5005",
-				"-an", "-f", "rawvideo", "-vf", "scale=32x18", "-pix_fmt", "gray", "pipe:1")
+				"-an", "-f", "rawvideo", "-vf", fmt.Sprintf("scale=%dx%d", telnet.Cfg.Width, telnet.Cfg.Height), "-pix_fmt", "gray", "pipe:1")
 
 			input, err := ffmpeg.StdinPipe()
 			if err != nil {