ChatGPT & Codex + calendar
A booking that is not in the user's calendar is a no-show waiting to happen. On iOS, WebViewGold lets users add an event to the Calendar app from a plain link to an .ics file, so your ChatGPT & Codex app needs nothing more than a URL that returns the event. Android has no dedicated calendar API in WebViewGold; here is what works there instead.
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WebViewGold is set up for Calendar (formerly iCal): a normal link to an .ics file lets the user add the entry to the iPhone or iPad calendar. No URL scheme, no JavaScript bridge, and the web app never reads the user's calendar; it only offers an event.
The Android documentation has no calendar API. Two routes work: add .ics to downloadableExtension in Config.java so the file is downloaded and can be opened with a calendar app that imports .ics files, and offer an "Add to Google Calendar" link that opens outside the app.
Your server returns a small text file (a VCALENDAR with one VEVENT) for each booking, class or appointment. The same URL serves the website, the iOS app and the Android download.
Paste this into ChatGPT & Codex to implement the web-app side. Review the result, publish, then test inside the WebViewGold app.
Prompt for Codex: Add calendar export for bookings, compatible with the WebViewGold app wrapper, and open a pull request. Create GET /calendar/:token.ics (random token per booking) returning one VEVENT with a stable UID, DTSTAMP, DTSTART and DTEND in UTC ending in Z, SUMMARY, LOCATION, DESCRIPTION with the booking URL and a VALARM one hour before, served as text/calendar; charset=utf-8. Use a maintained iCalendar library. Add calendarLinks(booking) that returns this URL and a calendar.google.com/calendar/render?action=TEMPLATE link. Show the .ics link on all platforms and the Google link when navigator.userAgent contains WebViewGold-Android. If appointments are parsed from free text with the OpenAI API, require structured JSON with ISO 8601 times and a time zone and build the file from it on the server. Add tests and document the rules in AGENTS.md.
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About an hour, most of it the .ics endpoint.
Add a route such as /calendar/BOOKING_TOKEN.ics that returns the event with Content-Type: text/calendar; charset=utf-8. Keep the path ending in .ics, as in the WebViewGold example, and use an unguessable token instead of relying on the login session.
A stable UID per booking, DTSTAMP, DTSTART and DTEND in UTC (ending in Z), SUMMARY, LOCATION and a DESCRIPTION with a link back to the booking. Escape commas and semicolons in text.
A plain <a href="https://yourdomain.com/calendar/TOKEN.ics">. Do not open it in a new window or with target="_blank"; a web view has nowhere to show one.
Add .ics to downloadableExtension in Config.java for the download route, and show an "Add to Google Calendar" link with calendar.google.com in BROWSER_BLACKLIST, so it opens in the system browser, where most users are signed in to Google, instead of inside the web view.
Add an event on an iPhone, then check the time zone, the duration and the link in the description. On Android, try phones from two manufacturers; calendar apps differ in how they open downloaded .ics files.
This is all a calendar needs. Lines end with CRLF in the iCalendar spec; libraries handle that for you. Server side of your stack: Your own API or serverless functions.
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//YourApp//Bookings//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
UID:[email protected]
DTSTAMP:20261101T120000Z
DTSTART:20261205T170000Z
DTEND:20261205T180000Z
SUMMARY:Yoga class
LOCATION:Studio 2\, 14 Main Street
DESCRIPTION:Manage your booking: https://yourdomain.com/bookings/123
BEGIN:VALARM
TRIGGER:-PT1H
ACTION:DISPLAY
DESCRIPTION:Yoga class in one hour
END:VALARM
END:VEVENT
END:VCALENDARThe .ics link everywhere, the Google Calendar link as an extra on Android and desktop:
// Custom user agents: "... WebViewGold-iOS" (Config.swift), "... WebViewGold-Android" (Config.java)
var ua = navigator.userAgent;
var IS_ANDROID_APP = ua.indexOf("WebViewGold-Android") !== -1;
var IS_IOS_APP = ua.indexOf("WebViewGold-iOS") !== -1;
function icsUrl(b) { return "https://yourdomain.com/calendar/" + b.token + ".ics"; }
function googleCalendarUrl(b) {
var f = function (d) { return d.toISOString().replace(/[-:]|\.\d{3}/g, ""); };
return "https://calendar.google.com/calendar/render?action=TEMPLATE" +
"&text=" + encodeURIComponent(b.title) +
"&dates=" + f(b.start) + "/" + f(b.end) +
"&details=" + encodeURIComponent(b.url) +
"&location=" + encodeURIComponent(b.location);
}
// Render: always the .ics link; the Google link unless IS_IOS_APPNot a dedicated one; the calendar integration in the docs is iOS only. On Android, offer the .ics file as a download (add .ics to downloadableExtension in Config.java) and an Add to Google Calendar link that opens outside the app.
No. The .ics flow only offers an event that the user adds. Availability belongs on your server, based on your own booking data.
Yes, inside the .ics file: an RRULE line for repeating classes and a VALARM block for a reminder. How the reminder appears depends on the user's calendar app; for reminders you control, use push notifications.
A small server route builds the text. For one event no library is needed, though ical-generator (Node) or icalendar (Python) helps with recurring events and escaping. Ask ChatGPT & Codex for an endpoint that returns text/calendar for a booking token.
Yes. The same .ics URL downloads or opens the event in desktop and mobile browsers, so one button serves the website and both apps.
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