add support for websockets api

lib/jambonz/monkey-patch-ws.js

@@ -0,0 +1,44 @@
+const assert = require('assert');
+const Websocket = require('ws');
+const {WebhookResponse} = require('@jambonz/node-client');
+
+module.exports = (ws, {logger, req}) => {
+  assert(ws instanceof Websocket);
+  ws.locals = {logger, req, url: req.url, originalUrl: req.url};
+
+  /* helper for sending an ack to jambonz */
+  ws.ack = (msgid, res) => {
+    let msg = {
+      type: 'ack',
+      msgid
+    };
+    if (res) msg = {...msg, data: res};
+    try {
+      logger.info({msg}, 'sending ack');
+      ws.send(JSON.stringify(msg));
+    } catch (err) {
+      logger.error({err}, 'Error sending ack to jambonz');
+    }
+  };
+
+  ws.sendCommand = (command, call_sid, payload) => {
+    payload = payload instanceof WebhookResponse ? payload.toJSON() : payload;
+    assert.ok(typeof call_sid === 'string', 'invalid or missing call_sid');
+    assert.ok(typeof payload === 'object' && Object.keys(payload).length > 0,
+      'invalid or missing payload');
+    //TODO: validate command
+
+    const msg = {
+      type: 'command',
+      command,
+      call_sid,
+      data: payload
+    };
+    try {
+      logger.info({msg}, 'sending command');
+      ws.send(JSON.stringify(msg));
+    } catch (err) {
+      logger.error({err}, `Error sending command ${command} to jambonz`);
+    }
+  };
+};