API & Config | P2P Streaming Engine

# Create instance

# var engine = new P2PEngineDash(player, {p2pConfig: [opts]});

Create a new P2PEngineDash instance, player is an instance of dashjs#MediaPlayer .

If opts is specified, then the default options (shown below) will be overridden.

Field	Type	Default	Description
logLevel	string\|boolean	'error'	Print log level(warn, error, none，false=none, true=warn).
wsSignalerAddr	string	'wss://signal.cdnbye.com'	The address of signal server.
announce	string	'https://tracker.cdnbye.com/v1'	The address of tracker server.
memoryCacheLimit	Object	{"pc": 1024 * 1024 * 512, "mobile": 1024 * 1024 * 256}	The max size of binary data that can be stored in the cache.
p2pEnabled	boolean	true	Enable or disable p2p engine.
wifiOnly	boolean	false	Only allow uploading on Wi-Fi and Ethernet.
dcDownloadTimeout	number	25	Max download timeout for WebRTC datachannel.
webRTCConfig	Object	{}	A Configuration dictionary providing options to configure WebRTC connections.
useHttpRange	boolean	false	Use HTTP ranges requests where it is possible. Allows to continue (and not start over) aborted P2P downloads over HTTP(True in live mode by default).
channelIdPrefix	string	''	Required while using customized channelId(5 <= length <= 15), recommended to set it as the unique identifier of your organization.

# P2PEngineDash API

# P2PEngineDash.version (static)

Get the version of P2PEngineDash.

# P2PEngineDash.protocolVersion (static)

Get the version of P2P protocol.

# P2PEngineDash.isSupported() (static method)

Returns true if WebRTC data channel is supported by the browser.

# engine.enableP2P()

Resume P2P if it has been stopped.

# engine.disableP2P()

Disable engine to stop p2p and free used resources.

# engine.destroy()

Stop p2p and free used resources.

# P2PEngineDash Events

# engine.on('peerId', function (peerId) {})

Emitted when the peer Id of this client is obtained from server.

# engine.on('peers', function (peers) {})

Emitted when successfully connected with new peer.

# engine.on('stats', function (stats) {})

Emitted when data is downloaded/uploaded.
stats.totalHTTPDownloaded: total data downloaded by HTTP(KB).
stats.totalP2PDownloaded: total data downloaded by P2P(KB).
stats.totalP2PUploaded: total data uploaded by P2P(KB).
stats.p2pDownloadSpeed: p2p download speed(KB/s).

# engine.on('serverConnected', function (connected) {})

Emitted when websocket is opened/closed.

# engine.on('exception', function (e) {})

Emitted when exception occured.
e.code: Exception identifier（TRACKER_EXPT SIGNAL_EXPT DASHJS_EXPT）
e.message: Exception message
e.stack: Exception stack

# Get p2p information from p2pConfig

p2pConfig: {
    getStats: function (totalP2PDownloaded, totalP2PUploaded, totalHTTPDownloaded, p2pDownloadSpeed) {
        // get the downloading statistics
    },
    getPeerId: function (peerId) {
        // get peer Id
    },
    getPeersInfo: function (peers) {
        // get peers information
    }
}

# Advanced Usage

# Dynamic MPD path issue

Some MPD urls play the same live/vod but have different paths on them. For example, example.com/clientId1/streamId.mpd and example.com/clientId2/streamId.mpd. In this case, you can format a common channelId for them.

// Set channelIdPrefix in p2pConfig before setting channelId!
p2pConfig: {
    channelIdPrefix: YOUR_UNIQUE_ID,
    channelId: function (mpdUrl) {
        const videoId = extractVideoIdFromUrl(mpdUrl);   // make a channelId by removing the different part which is defined by yourself
        return videoId;
    },
    segmentId: function (streamId, sn, url, range) {
        return ""+sn;
    },
}

# Dynamic segment path issue

Like dynamic mpd path issue, you should format a common segmentId for the same segment file. You can override the segment ID like this:

p2pConfig: {
    /*
        streamId: The id of stream
        sn: The serial number of segment
        segmentUrl: The url of segment
        range: bytes range of segmentUrl
     */
    segmentId: function (streamId, sn, segmentUrl, range) {
        const segId = extractSegmentIdFromUrl(segmentUrl);
        return segId;
    }
}

# Config STUN Servers

p2pConfig: {
    webRTCConfig: { 
        config: {         // custom webrtc configuration (used by RTCPeerConnection constructor)
            iceServers: [
                { urls: 'stun:stun.l.google.com:19302' }, 
                { urls: 'stun:global.stun.twilio.com:3478?transport=udp' }
            ] 
        }
    }
}

# Allow Http Range Request

If http range request is activated, we are able to get chunks of data from peer and then complete the segments by getting other chunks from the CDN, thus, reducing your CDN bandwidth. Besides, the code below is needed：

p2pConfig: {
    useHttpRange: true,
}

# How to Check Segment Validity

Sometimes we need to prevent a peer from sending a fake segment (such as the bittorrent with a hash function). CDNBye provides a validation callback with buffer of the downloaded segment, developer should implement the actual validator. For example, you can create a program that generates hashes for the segments and stores them in a specific file or injects into m3u8 playlist files the hashes information. If the callback returns false, then the segment is not valid.

p2pConfig: {
   validateSegment: function (level, sn, buffer) {
       var hash = hashFile.getHash(level, sn);
       return hash === md5(buffer);
   }
}