videoStream.js

let lastFrameObj = {
    lastFrame: null
};

let videoStream = {
    getLastFrame: () => {
        return lastFrameObj.lastFrame;
    },
    acceptConnections: function(expressApp, cameraOptions, resourcePath, isVerbose){
        const raspberryPiCamera = require('raspberry-pi-camera-native');

        if(!cameraOptions){
            cameraOptions = {
                width: 1280,
                height: 720,
                fps: 16,
                encoding: 'JPEG',
                quality: 7
            };
        }

        // start capture
        raspberryPiCamera.start(cameraOptions);
        if(isVerbose) {
            console.log('Camera started.');
        }

        if(typeof resourcePath === 'undefined' || !resourcePath){
            resourcePath = '/stream.mjpg';
        }

        expressApp.get(resourcePath, (req, res) => {

            res.writeHead(200, {
                'Cache-Control': 'no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0',
                Pragma: 'no-cache',
                Connection: 'close',
                'Content-Type': 'multipart/x-mixed-replace; boundary=--myboundary'
            });
            if(isVerbose)
                console.log('Accepting connection: '+req.hostname);

            // add frame data event listener
        
            let isReady = true;
        
            let frameHandler = (frameData) => {
                try{
                    if(!isReady){
                        return;
                    }
        
                    isReady = false;
        
                    if(isVerbose)
                        console.log('Writing frame: '+frameData.length);

                    lastFrameObj.lastFrame = frameData;

                    res.write(`--myboundary\nContent-Type: image/jpg\nContent-length: ${frameData.length}\n\n`);
                    res.write(frameData, function(){
                        isReady = true;
                    });
        
        
                }
                catch(ex){
                    if(isVerbose)
                        console.log('Unable to send frame: '+ex);
                }
            }
        
            let frameEmitter = raspberryPiCamera.on('frame', frameHandler);
        
            req.on('close', ()=>{
                frameEmitter.removeListener('frame', frameHandler);

                if(isVerbose)
                    console.log('Connection terminated: '+req.hostname);
            });
        });
    }
}

module.exports = videoStream;