yebisu-client/main.go

package main

import (
	"context"
	"flag"
	"log"
	"net/http"
	"os"
	"os/signal"
	"time"

	"golang.org/x/crypto/blake2b"

	dev "github.com/vladimirvivien/go4vl/device"
	"github.com/vladimirvivien/go4vl/v4l2"

	"github.com/gorilla/websocket"
)

func sender(queue chan []byte, secret string, cooldown uint) {
	log.Println("start sender")

	h := make(http.Header, 1)
	h.Set("X-Secret", secret)

	for {
		ws, _, err := websocket.DefaultDialer.Dial("wss://yebi.su/ws", h)
		if err != nil {
			log.Println("dial error")

			continue
		}

		log.Println("connected")

		for {
			data := <-queue

			if err := ws.WriteMessage(websocket.BinaryMessage, data); err != nil {
				if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
					log.Println("connection lost")
				}

				break
			}

			time.Sleep(time.Duration(cooldown) * time.Millisecond)
		}

		ws.Close()
	}
}

func chunkBy[T any](items []T, chunkSize int) (chunks [][]T) {
	for chunkSize < len(items) {
		items, chunks = items[chunkSize:], append(chunks, items[0:chunkSize:chunkSize])
	}
	return chunks
}

func processor(inQueue chan []byte, outQueue chan []byte) {
	log.Println("start processor")

	for {
		data := <-inQueue

		newData := []byte{}
		for _, chunk := range chunkBy(data, 2) {
			newData = append(newData, chunk[0]^chunk[1])
		}

		data = newData

		newData = []byte{}
		for _, chunk := range chunkBy(data, 8) {
			var b byte = 0

			for j := 0; j < 8; j++ {
				if chunk[j]&1 != 0 {
					b |= (1 << (7 - j))
				}
			}

			newData = append(newData, b)
		}

		data = newData

		newData = []byte{}
		for _, chunk := range chunkBy(data, 32) {
			sum := blake2b.Sum256(chunk)

			newData = append(newData, sum[:]...)
		}

		outQueue <- newData
	}
}

func main() {
	var deviceName string
	var bufferSize uint
	var processorsCount uint
	var sendersCount uint
	var sendCooldown uint
	var ident string
	var secret string

	flag.StringVar(&deviceName, "device", "/dev/video0", "v4l2 device to capture from")
	flag.UintVar(&bufferSize, "bufferSize", 1024, "sending queue max capacity")
	flag.UintVar(&processorsCount, "processorsCount", 1, "count of processor goroutines")
	flag.UintVar(&sendersCount, "sendersCount", 1, "count of sender goroutines")
	flag.UintVar(&sendCooldown, "sendCooldown", 100, "send cooldown (in ms)")
	flag.StringVar(&ident, "ident", "", "yebi.su ident")
	flag.StringVar(&secret, "secret", "", "yebi.su secret")

	flag.Parse()

	if ident == "" {
		log.Panicln("ident not specified")
	}

	if secret == "" {
		log.Panicln("secret not specified")
	}

	secret = ident + " " + secret

	log.Printf("open v4l2 device: %s\n", deviceName)

	device, err := dev.Open(deviceName)
	if err != nil {
		log.Panicln("failed to open device")
	}

	defer device.Close()

	frameSizes, err := v4l2.GetFormatFrameSizes(device.Fd(), v4l2.PixelFmtYUYV)
	if err != nil {
		log.Panicln("failed to get supported frame sizes")
	}

	if err := device.SetPixFormat(v4l2.PixFormat{
		Width:       frameSizes[0].Size.MinWidth,
		Height:      frameSizes[0].Size.MinHeight,
		PixelFormat: v4l2.PixelFmtYUYV,
		Field:       v4l2.FieldNone,
	}); err != nil {
		log.Panicln("failed to set device pixel format")
	}

	processorQueue := make(chan []byte, bufferSize)
	senderQueue := make(chan []byte, bufferSize)

	defer close(processorQueue)
	defer close(senderQueue)

	for i := 0; i < int(sendersCount); i++ {
		go sender(senderQueue, secret, sendCooldown)
	}

	for i := 0; i < int(processorsCount); i++ {
		go processor(processorQueue, senderQueue)
	}

	log.Println("start recording")

	ctx, stop := context.WithCancel(context.TODO())

	if err := device.Start(ctx); err != nil {
		log.Panicln("failed to start recording on device")
	}

	defer stop()

	log.Println("start loop")

	interrupt := make(chan os.Signal, 1)
	signal.Notify(interrupt, os.Interrupt)

	for {
		select {
		case frame := <-device.GetOutput():
			if len(frame) != 0 {
				processorQueue <- frame
			}
		case <-interrupt:
			log.Println("interrupted")

			return
		}
	}
}