dual streams (#467)

* dual streams

* dual streams

* dual streams

* dual streams

* use sdp transform

lib/http-routes/api/create-call.js

@@ -10,6 +10,7 @@ const HttpRequestor = require('../../utils/http-requestor');
 const WsRequestor = require('../../utils/ws-requestor');
 const RootSpan = require('../../utils/call-tracer');
 const dbUtils = require('../../utils/db-utils');
+const { mergeSdpMedia, extractSdpMedia } = require('../../utils/sdp-utils');
 
 router.post('/', async(req, res) => {
   const {logger} = req.app.locals;
@@ -127,16 +128,35 @@ router.post('/', async(req, res) => {
 
     /* launch outdial */
     let sdp, sipLogger;
+    let dualEp;
+    let localSdp = ep.local.sdp;
+
+    if (req.body.dual_streams) {
+      dualEp = await ms.createEndpoint();
+      localSdp = mergeSdpMedia(localSdp, dualEp.local.sdp);
+      ep.on('destroy', () => {
+        dualEp.destroy();
+      });
+    }
+
     const connectStream = async(remoteSdp) => {
       if (remoteSdp !== sdp) {
-        ep.modify(sdp = remoteSdp);
+        sdp = remoteSdp;
+        if (req.body.dual_streams) {
+          const [sdpLegA, sdpLebB] = extractSdpMedia(remoteSdp);
+
+          await Promise.all([ep.modify(sdpLegA), dualEp.modify(sdpLebB)]);
+          await ep.bridge(dualEp);
+        } else {
+          ep.modify(sdp);
+        }
         return true;
       }
       return false;
     };
     Object.assign(opts, {
       proxy: `sip:${sbcAddress}`,
-      localSdp: ep.local.sdp
+      localSdp
     });
     if (target.auth) opts.auth = target.auth;
 

lib/utils/sdp-utils.js

@@ -1,7 +1,32 @@
+const sdpTransform = require('sdp-transform');
+
 const isOnhold = (sdp) => {
   return sdp && (sdp.includes('a=sendonly') || sdp.includes('a=inactive'));
 };
 
-module.exports = {
-  isOnhold
+const mergeSdpMedia = (sdp1, sdp2) => {
+  const parsedSdp1 = sdpTransform.parse(sdp1);
+  const parsedSdp2 = sdpTransform.parse(sdp2);
+
+  parsedSdp1.media.push(...parsedSdp2.media);
+  return sdpTransform.write(parsedSdp1);
+};
+
+const extractSdpMedia = (sdp) => {
+  const parsedSdp1 = sdpTransform.parse(sdp);
+  if (parsedSdp1.media.length > 1) {
+    parsedSdp1.media = [parsedSdp1.media[0]];
+    const parsedSdp2 = sdpTransform.parse(sdp);
+    parsedSdp2.media = [parsedSdp2.media[1]];
+
+    return [sdpTransform.write(parsedSdp1), sdpTransform.write(parsedSdp2)];
+  } else {
+    return [sdp, sdp];
+  }
+};
+
+module.exports = {
+  isOnhold,
+  mergeSdpMedia,
+  extractSdpMedia
 };