added the tab sepecific code in extension

Author: saminur

extension/writing-process/src/background.js

@@ -12,7 +12,7 @@ var RAW_DEBUG = false;
 var WEBSOCKET_SERVER_URL = "wss://learning-observer.org/wsapi/in/";
 
 import { googledocs_id_from_url } from './writing_common';
-
+import { tab_id_from_url } from './writing_common';
 import * as loEvent from 'lo_event/lo_event/lo_event.js';
 import * as loEventDebug from 'lo_event/lo_event/debugLog.js';
 import { websocketLogger } from 'lo_event/lo_event/websocketLogger.js';
@@ -210,6 +210,7 @@ chrome.webRequest.onBeforeRequest.addListener(
                   versus GMT. */
                 event = {
                     'doc_id': googledocs_id_from_url(request.url),
+                    'tab_id': tab_id_from_url(request.url),
                     'url': request.url,
                     'bundles': JSON.parse(formdata.bundles),
                     'rev': formdata.rev,
@@ -223,6 +224,7 @@ chrome.webRequest.onBeforeRequest.addListener(
                 */
                 event = {
                     'doc_id': googledocs_id_from_url(request.url),
+                    'tab_id': tab_id_from_url(request.url),
                     'url': request.url,
                     'formdata': formdata,
                     'rev': formdata.rev,

extension/writing-process/src/writing_common.js

@@ -78,6 +78,21 @@ export function googledocs_id_from_url(url) {
     return null;
 }
 
+export function tab_id_from_url(url) {
+    /*
+      Given a URL like:
+        https://docs.google.com/document/d/<doc_id>/edit?tab=t.95yb7msfl8ul
+      extract the associated tab ID:
+        t.95yb7msfl8ul
+      Return null if not a valid URL or tab param.
+    */
+    var match = url.match(/[?&]tab=([^&]+)/i);
+    if (match) {
+        return match[1];
+    }
+    return null;
+}
+
 var writing_lasthash = "";
 function unique_id() {
     /*