feature: renew RTSP session

Author: fabianeichfeldt

lib/components/rtsp-session/rtspsession-component.js

@@ -135,6 +135,10 @@ class RtspSessionComponent extends Component {
     this._callHistory = []
     this._state = IDLE
     this._waiting = false
+    if (this._renewSessionInterval) {
+      clearInterval(this._renewSessionInterval)
+    }
+    this._renewSessionInterval = null
 
     this._contentBase = null
     this._sessionId = null
@@ -157,7 +161,23 @@ class RtspSessionComponent extends Component {
     if (!this._sessionId && !ended) {
       // Response on first SETUP
       this._sessionId = Rtsp.sessionId(msg.data)
+      const sessionTimeout = Rtsp.sessionTimeout(msg.data)
+      if (sessionTimeout !== null) {
+        // The server specified that sessions will timeout if not renewed.
+        // In order to keep it alive we need periodically send a RTSP_OPTIONS message
+        if (this._renewSessionInterval) {
+          clearInterval(this._renewSessionInterval)
+        }
+        this._renewSessionInterval = setInterval(
+          () => {
+            this._enqueue({ method: RTSP_OPTIONS })
+            this._dequeue()
+          },
+          (sessionTimeout - 5) * 1000 // timeout minus 5 seconds.
+        )
+      }
     }
+
     if (!this._contentBase) {
       this._contentBase = Rtsp.contentBase(msg.data)
     }
@@ -290,6 +310,10 @@ class RtspSessionComponent extends Component {
       this._callStack = []
     }
     this._state = IDLE
+    if (this._renewSessionInterval) {
+      clearInterval(this._renewSessionInterval)
+      this._renewSessionInterval = null
+    }
     this._dequeue()
   }
 

lib/components/rtsp-session/rtspsession-component.test.js

@@ -135,9 +135,11 @@ describe('session', () => {
     test('should get the session from a Response containing session info', () => {
       const s = new RtspSessionComponent({ uri: 'whatever' })
       expect(s._sessionId).toEqual(null)
+      expect(s._renewSessionInterval).toBeNull()
       const res = Buffer.from(setupResponse)
       s.incoming.write({ data: res, type: RTSP })
       expect(s._sessionId).toEqual('Bk48Ak7wjcWaAgRD')
+      expect(s._renewSessionInterval).not.toBeNull()
     })
 
     test('should emit a Request using SETUP command', (done) => {

lib/utils/protocols/fixtures.js

@@ -78,6 +78,16 @@ Date: Wed, 03 Jun 2015 14:23:42 GMT
 
 `.split('\n').join('\r\n');
 
+exports.setupResponseNoTimeout = `RTSP/1.0 200 OK
+CSeq: 5
+RTP-Info: url=rtsp://192.168.0.3/axis-media/media.amp/stream=0?resolution=176x144&fps=1;seq=10176;rtptime=2419713327
+Range: npt=now-
+Server: GStreamer RTSP server
+Session: Bk48Ak7wjcWaAgRD
+Date: Wed, 03 Jun 2015 14:23:42 GMT
+
+`.split('\n').join('\r\n');
+
 exports.teardownResponse = `RTSP/1.0 200 OK
 CSeq: 5
 Server: GStreamer RTSP server

lib/utils/protocols/rtsp.js

@@ -35,6 +35,22 @@ const sessionId = (buffer) => {
   return val ? val.split(';')[0] : null
 }
 
+const sessionTimeout = (buffer) => {
+  const val = extractHeaderValue(buffer, 'Session')
+  if (val === null) {
+    return null
+  }
+  const timeoutToken = 'timeout='
+  const timeoutPosition = val.indexOf(timeoutToken)
+  if (timeoutPosition !== -1) {
+    let timeoutVal = val.substring(timeoutPosition + timeoutToken.length)
+    timeoutVal = timeoutVal.split(';')[0]
+    let parsedTimeout = parseInt(timeoutVal)
+    return (isNaN(parsedTimeout)) ? null : parsedTimeout
+  }
+  return null
+}
+
 const statusCode = (buffer) => {
   return Number(buffer.toString('ascii', 9, 12))
 }
@@ -86,6 +102,7 @@ const bodyOffset = (chunk) => {
 module.exports = {
   sequence,
   sessionId,
+  sessionTimeout,
   statusCode,
   contentBase,
   connectionEnded,

lib/utils/protocols/rtsp.test.js

@@ -1,5 +1,5 @@
 const Rtsp = require('./rtsp')
-const { sdpResponse, sdpResponseLive555, setupResponse, teardownResponse } =
+const { sdpResponse, sdpResponseLive555, setupResponse, setupResponseNoTimeout, teardownResponse } =
   require('./fixtures')
 
 describe('Rtsp', () => {
@@ -21,6 +21,18 @@ describe('Rtsp', () => {
     })
   })
 
+  describe('sessionTimeout', () => {
+    it('should be null before SETUP', () => {
+      expect(Rtsp.sessionTimeout(Buffer.from(sdpResponse))).toBeNull()
+    })
+    it('should be extracted correctly when in a SETUP response', () => {
+      expect(Rtsp.sessionTimeout(Buffer.from(setupResponse))).toEqual(60)
+    })
+    it('should be null when not specified in a SETUP response', () => {
+      expect(Rtsp.sessionTimeout(Buffer.from(setupResponseNoTimeout))).toBeNull()
+    })
+  })
+
   describe('statusCode', () => {
     it('should return an integer', () => {
       expect(Rtsp.statusCode(Buffer.from(sdpResponseLive555))).toEqual(200)