Quick ICS → Calendar

A Chrome extension that turns Google Calendar's ~20-click .ics import into a two-click flow: click the toolbar icon, click a recently-downloaded .ics file, and its events are pushed straight into your chosen Google Calendar.

• 📂 Lists .ics files from your downloads, newest first
• 🖱️ One click imports every event in the file via the Google Calendar API
• ⚙️ Settings to pick the target calendar and limit the source folder
• 🔁 Handles all-day events, time zones, recurring events (RRULE), and folded lines
• 🧷 Manual file-picker fallback if direct file reading isn't enabled

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How it works (and its limits)

Chrome extensions are sandboxed and cannot freely scan ~/Downloads. This extension uses the chrome.downloads API, which lists every file Chrome itself downloaded — exactly the .ics files you grab from email/web. Files copied into the folder by other apps won't appear (use Pick a file manually… for those).

To read a file's contents it fetches file://<path>, which requires the extension's "Allow access to file URLs" toggle (one-time, step 5 below).

Importing uses the Google Calendar API with OAuth — no fragile clicking through the Calendar UI. That requires a one-time OAuth client (steps 1–4).

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Setup

1. Create a Google Cloud project & enable the Calendar API

1. Go to https://console.cloud.google.com/ → create a project (any name).
2. APIs & Services → Library → search Google Calendar API → Enable.

2. Configure the OAuth consent screen

1. APIs & Services → OAuth consent screen → User type External → Create.
2. Fill in the app name and your email where required.
3. On Test users → Add users, add the exact Google account you'll sign in with (in the newer console this is under Audience). Keeping the app in Testing is fine for personal use — no Google verification needed — but an account that isn't on this list will be rejected with 403 access_denied.

3. Load the extension to get its ID

1. Make a copy of manifest.json.orig named manifest.json in this folder. (The repo ships only the template; your working manifest.json is git-ignored so your client ID is never committed.)
2. Open chrome://extensions, enable Developer mode (top-right).
3. Load unpacked → select this folder.
4. Copy the extension's ID (a long string of letters under its name).

4. Create the OAuth client ID

1. APIs & Services → Credentials → Create credentials → OAuth client ID.
2. Application type: Chrome Extension.
3. Paste the extension ID from step 3 into the Item ID field → Create.
4. Copy the Client ID that Google now generates — this is the value you put in the manifest, and it is not the same as the extension ID.
   • ✅ Client ID: digits, a dash, then random chars — 123456789012-a1b2c3d4...apps.googleusercontent.com
   • ❌ Extension ID: 32 letters, no digits, no dash — e.g. nbkpnc...lbemi (that's the Item ID you typed in; don't paste it back into the manifest)
5. In the manifest.json you created in step 3, replace REPLACE_WITH_YOUR_CLIENT_ID.apps.googleusercontent.com with your Client ID.
6. Back on chrome://extensions, click the reload ↻ icon on the extension.

Keep this folder where it is — moving it can change the extension ID, which would break the OAuth client mapping. If that happens, repeat step 4 with the new ID.

5. Allow file reading

On chrome://extensions → this extension → Details → turn on "Allow access to file URLs." (Without it, use the manual file picker.)

6. Configure & use

1. Click the toolbar icon → the ⚙ gear → Settings.
2. Click Connect Google Calendar, approve access, and pick your target calendar and optional source folder. Save.
3. Done. From now on: click the icon → click an .ics file → imported. ✅

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Files

File	Purpose
manifest.json	Extension manifest (MV3); holds your OAuth client ID
popup.html/.css/.js	The toolbar popup: lists files and triggers imports
options.html/.css/.js	Settings: connect account, choose calendar & folder
lib/ics.js	RFC 5545 .ics → Calendar API event parser
lib/gcal.js	OAuth + Google Calendar API client
make_icons.py	Regenerates the PNG icons in icons/

Troubleshooting

"Check the OAuth client ID in manifest.json…" / auth fails instantly You probably pasted the extension ID instead of the generated Client ID. They look different — see step 4 above. Go to Credentials → OAuth 2.0 Client IDs, open your Chrome Extension client, copy the Client ID (NNNN-xxxx.apps.googleusercontent.com) into manifest.json, and reload the extension (↻ on chrome://extensions).

Error 403: access_denied Your account isn't authorized for the app yet. This is the OAuth consent screen, not your client ID. Fix it:

1. APIs & Services → OAuth consent screen (or Audience) → confirm Publishing status: Testing.
2. Test users → Add users → add the account you're signing in with → Save.
3. Make sure that account matches your Chrome profile's Google account — the consent popup uses whichever account the profile is signed into. If your profile is a personal Gmail, add that, not a different address.
4. Retry Connect.

Google Workspace accounts: if your domain (e.g. a @your-company address) restricts third-party apps, test-user status alone won't be enough — a Workspace admin must allow the app (admin.google.com → Security → API controls), or sign in with a personal Gmail added as a test user instead.

The file list is empty Only files Chrome downloaded appear. Files placed in the folder by other apps won't show — use Pick a file manually… in the popup.

"Couldn't read the file directly" Turn on "Allow access to file URLs" for the extension (chrome://extensions → Details), or use the manual picker.

Notes & limitations

• Events are created fresh on each import; re-importing the same file makes duplicates (the API has no built-in de-dupe here).
• Time zones use the .ics file's TZID; floating times (no zone) are interpreted by Google Calendar in your calendar's default zone.
• Custom VTIMEZONE definitions are ignored — standard IANA names work best.
• Scopes requested: read your calendar list, and create events. Nothing else.