hackash/rtsp-stream

A transport agnostic RTSP serial multiplexer module for Node

rtsp-stream

A transport agnostic RTSP serial multiplexer module for Node. Use it to encode or decode RTSP data streams.

This project aims for 100% compliance with RFC 2326. If you find something missing, please open an issue.

Protocol features currently supported:

• Client to server requests/responses
• Server to client requests/responses
• Persistent transport connections
• Connectionless mode (this is just data stream parsing, so sessions must be handled elsewhere)
• Pipelining

Protocol features that are out of scope for this module:

• Session handling

Installation

npm install rtsp-stream

Usage

Let's set up a TCP server, listen on port 5000 and have it respond to RTSP requests:

var net = require('net')
var rtsp = require('rtsp-stream')

var server = net.createServer(function (socket) {
  var decoder = new rtsp.Decoder()
  var encoder = new rtsp.Encoder()

  decoder.on('request', function (req) {
    console.log(req.method, req.uri)

    // output the request body
    req.pipe(process.stdout)

    req.on('end', function () {
      // prepare a new response to the client
      var res = encoder.response()

      res.setHeader('CSeq', req.headers['cseq'])
      res.end('Hello World!')
    })
  })

  // pipe the data from the client into the decoder
  socket.pipe(decoder)

  // ...and pipe the response back to the client from the encoder
  encoder.pipe(socket)
})

server.listen(5000)

Server -> Client request

In some scenarios the server will make a request to the client. Here is what the RFC have to say about that:

Unlike HTTP, RTSP allows the media server to send requests to the media client. However, this is only supported for persistent connections, as the media server otherwise has no reliable way of reaching the client. Also, this is the only way that requests from media server to client are likely to traverse firewalls.

In the example below, the server sends two request to the client using the Encoder object:

decoder.on('response', function (res) {
  console.log('Response to CSeq %s (code %s)', res.headers['cseq'], res.statusCode)

  // output the response body
  res.pipe(process.stdout)
})

var body = 'Hello World!'
var options = {
  method: 'OPTIONS',
  uri: '*',
  headers: {
    CSeq: 1,
    'Content-Length': Buffer.byteLength(body)
  }
  body: body
}

encoder.request(options, function () {
  console.log('done sending request 1 to client')
})

var req = encoder.request({ method: 'OPTIONS', uri: '*' })
req.setHeader('CSeq', 2)
req.setHeader('Content-Length', Buffer.byteLength(body))
req.end(body)

API

The rtsp-stream module exposes the following:

• STATUS_CODES - List of valid RTSP status codes
• Decoder - The decoder object
• Encoder - The encoder object
• IncomingMessage - A readable stream representing an incoming RTSP message. Can be either a request or a response. Given as the first argument to the Decoder request and response event
• OutgoingMessage - A writable stream representing an outgoing RTSP message. Can be either a request or a response
• Request - A writable stream of type OutgoingMessage representing an outgoing RTSP request. Generated by encoder.request()
• Response - A writable stream of type OutgoingMessage representing an outgoing RTSP response. Generated by encoder.response()

Decoder

A writable stream used to parse incoming RTSP data. Emits the following events:

Event: request

Emitted every time a new request header is found. The event listener is called with a single arguemnt:

• req - An rtspStream.IncomingMessage object

Event: response

Emitted every time a new response header is found. The event listener is called with a single arguemnt:

• res - An rtspStream.IncomingMessage object

Encoder

A readable stream. Outputs valid RTSP responses.

Encoder.response()

Returns a writable stream of type Response.

Encoder.request()

Returns a writable stream of type Request.

IncomingMessage

Exposes the body of the incoming RTSP message by implementing a readable stream interface.

Also exposes the RTSP start-line using the following properties:

IncomingMessage.rtspVersion

The RTSP protocol version used in the message. By all intents and purposes you can expect this to always be 1.0.

IncomingMessage.method

Only used if the message is a request

The RTSP request method used in the request. The following are standardized in RFC 2326, but others are also used in the wild:

• DESCRIBE
• ANNOUNCE
• GET_PARAMETER
• OPTIONS
• PAUSE
• PLAY
• RECORD
• SETUP
• SET_PARAMETER
• TEARDOWN

IncomingMessage.uri

Only used if the message is a request

The RTSP request URI used.

IncomingMessage.statusCode

Only used if the message is a response

The RTSP response code used.

IncomingMessage.statusMessage

Only used if the message is a response

The message matching the RTSP response code used.

IncomingMessage.headers

An object containing the headers used on the RTSP request. Object keys represent header fields and the object values the header values.

All header field names are lowercased for your convenience.

Values from repeating header fields are joined in an array.

OutgoingMessage

A writable stream representing an outgoing RTSP message. Can be either a request or a response.

OutgoingMessage.headersSent

A boolean. true if the response headers have flushed.

OutgoingMessage.setHeader(name, value)

Set a header to be sent along with the RTSP response body. Throws an error if called after the headers have been flushed.

OutgoingMessage.getHeader(name)

Get a header value. Case insensitive.

OutgoingMessage.removeHeader(name)

Remove a header so it is not sent to the client. Case insensitive. Throws an error if called after the headers have been flushed.

Request

A writable stream of type OutgoingMessage representing an outgoing RTSP request. Generated by encoder.request().

Response

A writable stream of type OutgoingMessage representing an outgoing RTSP response. Generated by encoder.response().

Response.statusCode

The status code used in the response. Defaults to 200. For alist of valid status codes see the rtspStream.STATUS_CODES object.

Response.writeHead([statusCode[, statusMessage][, headers]])

Force writing of the RTSP response headers to the client. Will be called automatically on the first to call to either response.write() or response.end().

Throws an error if called after the headers have been flushed.

Arguments:

• statusCode - Set a custom status code (overrides the response.statusCode property)
• statusMessage - Set a custom status message related to the status code (e.g. the default status message for the status code 200 is OK)
• headers - A key/value headers object used to set extra headers to be sent along with the RTSP response. This will augment the headers already set using the response.setHeader() function

License

MIT