feat: convenience pipeline to extract SDP

Author: Steven Vancoillie

lib/pipelines/index.browser.ts

@@ -8,3 +8,4 @@ export * from './html5-canvas-pipeline'
 export * from './html5-video-pipeline'
 export * from './html5-video-metadata-pipeline'
 export * from './metadata-pipeline'
+export * from './ws-sdp-pipeline'

lib/pipelines/ws-sdp-pipeline.ts

@@ -0,0 +1,64 @@
+import { RtspConfig, RTSP_METHOD } from '../components/rtsp-session'
+import { WSConfig } from '../components/ws-source/openwebsocket'
+import { WSSource } from '../components/ws-source'
+import { AuthConfig, Auth } from '../components/auth'
+import { RtspPipeline } from './rtsp-pipeline'
+
+export interface TransformConfig {
+  ws?: WSConfig
+  rtsp?: RtspConfig
+  auth?: AuthConfig
+}
+
+/**
+ * Pipeline that can receive the SDP object for an RTS stream.
+ *
+ * @class WsSdpPipeline
+ * @extends {RtspPipeline}
+ */
+export class WsSdpPipeline extends RtspPipeline {
+  public onServerClose?: () => void
+  public ready: Promise<void>
+
+  private _src?: WSSource
+
+  /**
+   * Creates an instance of Html5VideoPipeline.
+   * @param {any} [config={}] Component options
+   * @memberof Html5VideoPipeline
+   */
+  constructor(config: TransformConfig) {
+    const { ws: wsConfig, rtsp: rtspConfig, auth: authConfig } = config
+
+    super(rtspConfig)
+
+    if (authConfig) {
+      const auth = new Auth(authConfig)
+      this.insertBefore(this.rtsp, auth)
+    }
+
+    const waitForWs = WSSource.open(wsConfig)
+    this.ready = waitForWs.then(wsSource => {
+      wsSource.onServerClose = () => {
+        this.onServerClose && this.onServerClose()
+      }
+      this.prepend(wsSource)
+      this._src = wsSource
+    })
+  }
+
+  close() {
+    this._src && this._src.outgoing.end()
+  }
+
+  get sdp() {
+    return this.ready.then(() => {
+      const sdpPromise = new Promise(resolve => {
+        this.rtsp.onSdp = resolve
+      })
+      this.rtsp.send({ method: RTSP_METHOD.DESCRIBE })
+      this.rtsp.send({ method: RTSP_METHOD.TEARDOWN })
+      return sdpPromise
+    })
+  }
+}