REFER should have sips contact if far end is using sips (#192)

Author: davehorton

lib/call-session.js

@@ -180,8 +180,8 @@ class CallSession extends Emitter {
       host = obj.host;
       proxy = `sip:${featureServer}`;
     }
-    if (obj.user) uri = `${scheme}:${obj.user}@${host}`;
-    else uri = `${scheme}:${host}`;
+    if (obj.user) uri = `sip:${obj.user}@${host}`;
+    else uri = `sip:${host}`;
     this.logger.info(`uri will be: ${uri}, proxy ${proxy}`);
 
     const sendOfferToRtpEngine = async(remoteSdp) => {
@@ -1057,7 +1057,7 @@ Duration=${payload.duration} `
           // eslint-disable-next-line no-unused-vars
           'content-length':contentlength, 'refer-to':_referto, 'referred-by': referredby,
           // eslint-disable-next-line no-unused-vars
-          'X-Refer-To-Leave-Untouched': _leave,
+          'X-Refer-To-Leave-Untouched': _leave, contact: _contact,
           ...customHeaders
         } = req.headers;
 
@@ -1066,6 +1066,7 @@ Duration=${payload.duration} `
           headers: {
             'Refer-To': `<${stringifyUri(uri)}>`,
             'Referred-By': referredby,
+            'Contact': this.contactHeader,
             ...customHeaders
           }
         });