Reopened/Fix: User experienced big delay when posting the messages

src/libs/DateUtils.ts

@@ -71,6 +71,12 @@ Onyx.connect({
     },
 });
 
+let networkTimeSkew = 0;
+Onyx.connect({
+    key: ONYXKEYS.NETWORK,
+    callback: (value) => (networkTimeSkew = value?.timeSkew ?? 0),
+});
+
 /**
  * Get the day of the week that the week starts on
  */
@@ -359,6 +365,16 @@ function getDBTime(timestamp: string | number = ''): string {
     return datetime.toISOString().replace('T', ' ').replace('Z', '');
 }
 
+/**
+ * Returns the current time plus skew in milliseconds in the format expected by the database
+ */
+function getDBTimeWithSkew(): string {
+    if (networkTimeSkew > 0) {
+        return getDBTime(new Date().valueOf() + networkTimeSkew);
+    }
+    return getDBTime();
+}
+
 function subtractMillisecondsFromDateTime(dateTime: string, milliseconds: number): string {
     const date = zonedTimeToUtc(dateTime, 'UTC');
     const newTimestamp = subMilliseconds(date, milliseconds).valueOf();
@@ -728,6 +744,7 @@ const DateUtils = {
     setTimezoneUpdated,
     getMicroseconds,
     getDBTime,
+    getDBTimeWithSkew,
     setLocale,
     subtractMillisecondsFromDateTime,
     getDateStringFromISOTimestamp,

src/libs/HttpUtils.ts

@@ -5,6 +5,7 @@ import CONST from '@src/CONST';
 import ONYXKEYS from '@src/ONYXKEYS';
 import type {RequestType} from '@src/types/onyx/Request';
 import type Response from '@src/types/onyx/Response';
+import * as NetworkActions from './actions/Network';
 import * as ApiUtils from './ApiUtils';
 import HttpsError from './Errors/HttpsError';
 
@@ -25,17 +26,41 @@ Onyx.connect({
 // We use the AbortController API to terminate pending request in `cancelPendingRequests`
 let cancellationController = new AbortController();
 
+/**
+ * The API commands that require the skew calculation
+ */
+const addSkewList = ['OpenReport', 'ReconnectApp', 'OpenApp'];
+
+/**
+ * Regex to get API command from the command
+ */
+const APICommandRegex = /[?&]command=([^&]+)/;
+
 /**
  * Send an HTTP request, and attempt to resolve the json response.
  * If there is a network error, we'll set the application offline.
  */
 function processHTTPRequest(url: string, method: RequestType = 'get', body: FormData | null = null, canCancel = true): Promise<Response> {
+    const startTime = new Date().valueOf();
     return fetch(url, {
         // We hook requests to the same Controller signal, so we can cancel them all at once
         signal: canCancel ? cancellationController.signal : undefined,
         method,
         body,
     })
+        .then((response) => {
+            // We are calculating the skew to minimize the delay when posting the messages
+            const match = url.match(APICommandRegex)?.[1];
+            if (match && addSkewList.includes(match) && response.headers) {
+                const dateHeaderValue = response.headers.get('Date');
+                const serverTime = dateHeaderValue ? new Date(dateHeaderValue).valueOf() : new Date().valueOf();
+                const endTime = new Date().valueOf();
+                const latency = (endTime - startTime) / 2;
+                const skew = serverTime - startTime + latency;
+                NetworkActions.setTimeSkew(dateHeaderValue ? skew : 0);
+            }
+            return response;
+        })
         .then((response) => {
             // Test mode where all requests will succeed in the server, but fail to return a response
             if (shouldFailAllRequests || shouldForceOffline) {

src/libs/ReportUtils.ts

@@ -2412,7 +2412,7 @@ function buildOptimisticAddCommentReportAction(text?: string, file?: File): Opti
             ],
             automatic: false,
             avatar: allPersonalDetails?.[currentUserAccountID ?? -1]?.avatar ?? UserUtils.getDefaultAvatarURL(currentUserAccountID),
-            created: DateUtils.getDBTime(),
+            created: DateUtils.getDBTimeWithSkew(),
             message: [
                 {
                     translationKey: isAttachment ? CONST.TRANSLATION_KEYS.ATTACHMENT : '',

src/libs/actions/Network.ts

@@ -5,6 +5,10 @@ function setIsOffline(isOffline: boolean) {
     Onyx.merge(ONYXKEYS.NETWORK, {isOffline});
 }
 
+function setTimeSkew(skew: number) {
+    Onyx.merge(ONYXKEYS.NETWORK, {timeSkew: skew});
+}
+
 function setShouldForceOffline(shouldForceOffline: boolean) {
     Onyx.merge(ONYXKEYS.NETWORK, {shouldForceOffline});
 }
@@ -16,4 +20,4 @@ function setShouldFailAllRequests(shouldFailAllRequests: boolean) {
     Onyx.merge(ONYXKEYS.NETWORK, {shouldFailAllRequests});
 }
 
-export {setIsOffline, setShouldForceOffline, setShouldFailAllRequests};
+export {setIsOffline, setShouldForceOffline, setShouldFailAllRequests, setTimeSkew};

src/libs/actions/Report.ts

@@ -306,7 +306,7 @@ function addActions(reportID: string, text = '', file?: File) {
 
     // Always prefer the file as the last action over text
     const lastAction = attachmentAction ?? reportCommentAction;
-    const currentTime = DateUtils.getDBTime();
+    const currentTime = DateUtils.getDBTimeWithSkew();
     const lastComment = lastAction?.message?.[0];
     const lastCommentText = ReportUtils.formatReportLastMessageText(lastComment?.text ?? '');
 

src/types/onyx/Network.ts

@@ -7,6 +7,9 @@ type Network = {
 
     /** Whether we should fail all network requests */
     shouldFailAllRequests?: boolean;
+
+    /** Skew between the client and server clocks  */
+    timeSkew?: number;
 };
 
 export default Network;