bambu-go2rtc

camera-stream.go

// golang version of https://github.com/synman/bambu-go2rtc
// usage: ./camera-stream <accessCode> <hostname>
// with ffplay: ./camera-stream <accessCode> <hostname> | ffplay -hide_banner -fflags nobuffer -analyzeduration 10 -probesize 32 -i -
// tested on bambu lab a1 mini, the fps is really low for this device :(

package main

import (
	"bytes"
	"crypto/tls"
	"encoding/binary"
	"fmt"
	"io"
	"net"
	"os"
)

const username = "bblp"
const port = 6000

func main() {
	if len(os.Args) != 3 {
		fmt.Println("Usage: <executable> <accessCode> <hostname>")
		os.Exit(1)
	}

	accessCode := os.Args[1]
	hostname := os.Args[2]

	authData := []byte{
		0x40, 0x00, 0x00, 0x00, // '@'\0\0\0
		0x00, 0x30, 0x00, 0x00, // \0'0'\0\0
		0x00, 0x00, 0x00, 0x00, // \0\0\0\0
		0x00, 0x00, 0x00, 0x00, // \0\0\0\0
	}
	authData = append(authData, []byte(username)...)
	authData = append(authData, make([]byte, 32-len(username))...)
	authData = append(authData, []byte(accessCode)...)
	authData = append(authData, make([]byte, 32-len(accessCode))...)
	// fmt.Fprintf(os.Stderr, "authData: %q\n", authData)

	connect(hostname, port, authData)
}

func connect(hostname string, port int, authData []byte) error {
	conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", hostname, port))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Connection attempt failed: %s\n", err)
		return err
	}
	defer conn.Close()

	tlsConn := tls.Client(conn, &tls.Config{
		InsecureSkipVerify: true,
	})
	err = tlsConn.Handshake()
	if err != nil {
		fmt.Fprintf(os.Stderr, "TLS handshake failed: %s\n", err)
		return err
	}
	defer tlsConn.Close()

	_, err = tlsConn.Write(authData)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Write to socket failed: %s\n", err)
		return err
	}

	for true {
		header := make([]byte, 16)
		_, err = io.ReadFull(tlsConn, header)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Read error: %s\n", err)
			return err
		}
		length := binary.LittleEndian.Uint32(header[0:4])
		// fmt.Fprintf(os.Stderr, "packet header: %v\n", header)

		if !bytes.Equal(header[4:], []byte{
			0x00, 0x00, 0x00, 0x00,
			0x01, 0x00, 0x00, 0x00,
			0x00, 0x00, 0x00, 0x00,
		}) {
			// skip invalid packet
			continue
		}

		img := make([]byte, length)
		_, err = io.ReadFull(tlsConn, img)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Read error: %s\n", err)
			return err
		}

		if bytes.Equal([]byte{0xff, 0xd8, 0xff, 0xe0}, img[0:4]) &&
			bytes.Equal([]byte{0xff, 0xd9}, img[length-2:]) {
			// fmt.Fprintf(os.Stderr, "Img size: %d\n", len(img))
			os.Stdout.Write(img)
		}
	}
	return nil
}