org-gcal offers

• Fetch google calendar event
• Post/edit org element
• Sync between Org and Gcal

Data will be UTF-8 encoded for sync.

Follow the instructions at Installation, and then run org-gcal-fetch to download Google Calendar events into your Org-mode files using the Google Calendar API. Run org-gcal-fetch to retrieve new events and update events already retrieved, and run org-gcal-post-at-point on an Org-mode headline corresponding to a downloaded event to push updates to the events on the Google Calendar API server.

First time setup: on the initial run, in order to obtain the initial OAuth authorization, org-gcal will open a link in the browser to obtain authorization for the OAuth credentials generated in Installation. You will probably see a screen that says “This app isn’t verified”. You will need to click on the “Advanced” link to authorize the application:

• Emacs 26+
• Org mode 9.3+
• tkf/emacs-request
• jwiegley/alert
• ~persist~
• skeeto/emacs-aio
• rhaps0dy/emacs-oauth2-auto (actually using vendored fork telotortium/emacs-oauth2-auto)

  org-gcal is now available in the famous emacs package repo MELPA, so the recommended way is to install it through Emacs package management system.

  NOTE: persist lives in GNU ELPA. If you’re running Emacs 26.x with x < 3, you may need to add (setq gnutls-algorithm-priority "NORMAL:-VERS-TLS1.3") to your init.el to work around Emacs bug https://debbugs.gnu.org/34341 (more info).

WARNING: The steps described below stopped working on 28.02.2022 when Google deprecated the ability to retrieve OAuth 2.0 tokens via out-of-band redirect_uri. Please refer to #191 for more background and to track progress on resolving this issue.

1. Go to Google Developers Console
2. Create a project (with any name)
3. Click on the project
4. Click on the hamburger menu at the upper-left, then APIs & Services, then Credentials.
5. Set up a consent screen. Give the application a name and set it up as type “external application”, and accept the defaults for everything else. You should not need to verify the application, because only your user will be using it.
6. Once you’ve set up a consent screen (this is required), click on Create Credentials and Oauth client ID with Application type Desktop (or Other, if Desktop is not present).
7. Click on Create Client ID
8. Record the Client ID and Client secret for setup.
9. Under the same APIs & Services menu section, select Library
10. Scroll down to Calendar API. Click the Enable button to enable calendar API access to the app you created in steps 5 & 6.

    Go to Google setting page to check the calendar ID.

11. Go to Google setting page and click the gear-shaped settings icon in the upper right, then select “Settings” from the drop down list.
12. Select the “Setting for my Calendars” tab on the left, which will display a list of your calendars.
13. Select the calendar you would like to synchronize with. This will take you to the “Calendar Settings” page for that calendar. Near the end is a section titled “Integrate Calendar”. Following the XML, ICAL, and HTML tags, you will see your Calendar ID.
14. Copy the Calendar ID for use in the settings below, where you will use it as the first element in the org-gcal-fetch-file-alist for associating calendars with specific org files. You can associate different calendars with different org files, so repeat this for each calendar you want to use.

(setq org-gcal-client-id "your-id-foo.apps.googleusercontent.com"
      org-gcal-client-secret "your-secret"
      org-gcal-fetch-file-alist '(("your-mail@gmail.com" .  "~/schedule.org")
                                  ("another-mail@gmail.com" .  "~/task.org")))
(require 'org-gcal)

This package uses plstore as a dependency for storing OAuth tokens. In order to avoid getting prompted all the time for the password to your plstore, it is recommended that you put the following in your init.el:

(setq plstore-cache-passphrase-for-symmetric-encryption t)

Alternatively, you may want to use an asymmetric GPG key instead. The main advantage of this is that the key can be retrieved from gpg-agent instead. In particular, on many systems you can configure gpg-agent to read the key from the system keychain, which means that you should only need to enter the keychain password, instead of having to memorize and enter a separate password for plstore. As a bonus, you’ll be prompted fewer times to enter a password, and it’s easier to automatically run org-gcal unattended.

To do this, follow these steps:

1. Generate a new GPG key following [these instructions](https://docs.github.com/en/authentication/managing-commit-signature-verification/generating-a-new-gpg-key). You could reuse an existing one also, but it’s probably best to separate it from any other keys whose public keys you publish (Git signing, GPG-encrypted email, etc.).
2. Once you have a key, copy the long form of the GPG key ID you’d like to use (see the Github instructions above, or run gpg --list-secret-keys --keyid-format=long).
3. Add the key ID to the Emacs variable plstore-encrypt-to:

   (require 'plstore)
   (add-to-list 'plstore-encrypt-to '("GPG-key-id"))
       

4. Set up pinentry for gpg-agent, so that the password to decrypt the GPG key is stored in the system keychain. For example, on macOS you can follow [these instructions](https://gist.github.com/koshatul/2427643668d4e89c0086f297f9ed2130).

There’s no support for multiple accounts. If you want to use org-gcal with calendars from different accounts, you can give permissions to the account you configured via the calendar’s settings interface.

To get more detailed information you can check this link.

If you local timezone is different from the Calendar. You can use your local timezone to fetch events. Event will be fetched using timezone defined in org-gcal-local-timezone. Timezone string can be found from: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones.

To execute compile and regression tests, run make.

This will use your existing Emacs installation to generate a value of load-path that allows org-gcal to find all its dependencies, and save it to .load-path.el in this directory. To delete this and other temporary files, run make clean.

Once you’ve set up the basic settings (see Setting example), you can run org-gcal-fetch to fetch events into the files configured in org-gcal-fetch-file-alist. After the initial fetch, running org-gcal-fetch will retrieve newly-created events and update already-fetched events.

To create a Google Calendar event from an Org-mode event, it’s enough to run the org-gcal-post-at-point command on a simple headline:

* Event title

This will prompt you for the calendar ID, start time, and end time of the event. Therefore, if you’d like to create an event without user interaction (from a template, for example), you should set these fields before running org-gcal-post-at-point:

* Event title
:PROPERTIES:
:calendar-id: jjjjjjjjjjjfuuuk842fdok134@group.calendar.google.com
:END:
:org-gcal:
<2020-07-15 wed 09:15-09:30>

Event details

(can be multiple paragraphs).
:END:

After the event has been created, some Google Calendar API-specific fields will be set for future updates to the event:

* Event title
:PROPERTIES:
:calendar-id: jjjjjjjjjjjfuuuk842fdok134@group.calendar.google.com
:ETag:     "7777777777980000"
:ID:       xxxxxxxxxxa4jlcj0v998f4u18/jjjjjjjjjjjfuuuk842fdok134@group.calendar.google.com
:END:
:org-gcal:
<2020-07-15 wed 09:15-09:30>

Event details

(can be multiple paragraphs).
:END:

If you want to schedule the event in your Org Agenda, you can use the SCHEDULED property (set by org-schedule) instead of storing the date in the :org-gcal: drawer. The drawer will still be present to contain event details:

* Event title
SCHEDULED: <2020-07-15 wed 09:15-09:30>
:PROPERTIES:
:calendar-id: jjjjjjjjjjjfuuuk842fdok134@group.calendar.google.com
:ETag:     "7777777777980000"
:ID:       xxxxxxxxxxa4jlcj0v998f4u18/jjjjjjjjjjjfuuuk842fdok134@group.calendar.google.com
:END:
:org-gcal:
Event details

(can be multiple paragraphs).
:END:

After editing an event in Org mode, you can also run org-gcal-post-at-point to update the event on Google Calendar. The command org-gcal-sync does what org-gcal-fetch does, but also runs org-gcal-post-at-point on all events that you’ve edited in Org mode to update the corresponding events in Google Calendar.

org-gcal modifies the following Org-mode properties and drawers when updating an event from the Google Calendar API:

Title

contains the event summary (minus any TODO keywords or tags).

• Timestamps:

  SCHEDULED

  if the SCHEDULED attribute of a headline is present, org-gcal will maintain the start and end times of an event there rather than in a timestamp in the org-gcal drawer (see below).

• Properties:
  • calendar-id (can be modified using the =org-gcal-calendar-id-property= variable) :: contains the calendar ID of the calendar on which the event is maintained.
  • ETag (can be modified using the =org-gcal-etag-property= variable) :: contains the most recent ETag retrieved from the Google Calendar API for the event (see the Google Calendar API documentation). Used to support automatically updating the headline using the most recent event data from the API if it has changed on the server since it was last retrieved.

    **NOTE**: If the ETag property is present on a headline (even if empty ("")) and not equal to the value stored by the Calendar API, your event will be **overwritten** with the data from the server. In this case, you’ll see a notification for a HTTP 512. This is intended behavior. If your event is being overwritten when you don’t want it, remove the ETag property from your headline.

  ID

  contains <event_id>/<calendar_id> of the event, as provided by the Google Calendar API. Don’t change the ID manually, or else the event won’t be able to retrieved or updated from the headline.

• Drawers:

  org-gcal (can be modified using the =org-gcal-drawer-name= variable)

  contains the event description. Unless the timestamp is maintained using SCHEDULED, the initial line of this drawer contains the event start and end time, with the event description starting in the next paragraph.

Apart from these, all other attributes are preserved when an event is updated in any way.

Fetch Google calendar events for all calendar IDs in org-gcal-fetch-file-alist occurring between org-gcal-up-days before today and org-gcal-down-days after today. If the events have already been retrieved and can be located using their Org-mode headline IDs, update the event in place. Otherwise, insert it at the end of the file corresponding to the event’s calendar ID in org-gcal-fetch-file-alist. Does not update events on the server.

Like org-gcal-fetch, but also update events on the server if they have changed locally.

Fetch changes to Google calendar events to update entries in the current buffer, but don’t update events on server.

Sync entries in the current buffer with Google Calendar.

Update the event represented by the Org-mode headline at POINT on the server using the Google Calendar API.

If the event has changed on the server since it was last retrieved (detected using the ETag property), automatically update the headline using the event data from the server instead of updating the event on the server.

Delete the event represented by the Org-mode headline at POINT on the server using the Google Calendar API. This will not delete the Org-mode headline.

If the event has changed on the server since it was last retrieved (detected using the ETag property), automatically update the headline using the event data from the server instead of updating the event on the server.

If an event is deleted on the server, then updating an event (via org-gcal-post-at-point, org-gcal-sync, etc.) will optionally cancel and delete the corresponding Org mode headlines:

• org-gcal-update-cancelled-events-with-todo: if set (the default), mark all cancelled events with the org-gcal-cancelled-todo-keyword (default: CANCELLED). This keyword must be one defined in org-todo-keywords or it will be ignored.
• org-gcal-remove-api-cancelled-events: if set, delete Org headlines of cancelled events. The default value is 'ask, which means to prompt for deletion.
• org-gcal-remove-events-with-cancelled-todo: by default, avoid deleting Org headlines of events that are marked with org-gcal-cancelled-todo-keyword beforehand, to allow preserving a headline for a cancelled event from being deleted. Setting this to t always deletes headlines, even already cancelled ones.

Modify org-gcal-notify-p from t to nil

By default, org-gcal-recurring-events-mode is set to 'top-level, which means that new fetched events that are instances of recurring events will be inserted at the top level of the file for the calendar ID configured in org-gcal-fetch-file-alist:

* Meeting
SCHEDULED: <2020-08-07 Fri 11:00>
* Meeting
SCHEDULED: <2020-08-14 Fri 11:00>
* Meeting
SCHEDULED: <2020-08-21 Fri 11:00>
* Meeting
SCHEDULED: <2020-08-28 Fri 11:00>

If org-gcal-recurring-events-mode is instead set to 'nested, such events will be inserted as Org-mode child headlines under the headline for the parent event:

* Meeting
SCHEDULED: <2017-02-17 Fri 11:00>
** Meeting
SCHEDULED: <2020-08-07 Fri 11:00>
** Meeting
SCHEDULED: <2020-08-14 Fri 11:00>
** Meeting
SCHEDULED: <2020-08-21 Fri 11:00>
** Meeting
SCHEDULED: <2020-08-28 Fri 11:00>

Here the parent meeting has been running for several years, but only the instances of the meeting in the range given by org-gcal-down-days and org-gcal-up-days are fetched.

If you would like to customize the contents of event entries (for example, to add a property from the Google Calendar API that’s not automatically written to the Org-mode entry), you can add a function to the list org-gcal-after-update-entry-functions. For example, here is some code to add the Effort property to an entry based on the duration of the event (note that the current point is placed at the beginning of the entry when the function is called):

(defun my-org-gcal-set-effort (_calendar-id event _update-mode)
  "Set Effort property based on EVENT if not already set."
  (when-let* ((stime (plist-get (plist-get event :start)
                           :dateTime))
              (etime (plist-get (plist-get event :end)
                                :dateTime))
              (diff (float-time
                     (time-subtract (org-gcal--parse-calendar-time-string etime)
                                    (org-gcal--parse-calendar-time-string stime))))
              (minutes (floor (/ diff 60))))
    (let ((effort (org-entry-get (point) org-effort-property)))
      (unless effort
        (message "need to set effort - minutes %S" minutes)
        (org-entry-put (point)
                       org-effort-property
                       (apply #'format "%d:%02d" (cl-floor minutes 60)))))))
(add-hook 'org-gcal-after-update-entry-functions #'my-org-gcal-set-effort)

Because we used the deferred.el to perform asynchronous operations like calling request (via ~request-deferred~), normal Emacs debugging and stack traces tend not to be as useful as usual. The best way to debug is to run M-x org-gcal-toggle-debug, which sets a variety of debugging variables to ease debugging. The old values of the variables are saved so they can be restored by another call to M-x org-gcal-toggle-debug.

One of the most useful things this enables is logging of HTTP requests. Open the *request-log* buffer to see all requests issued by this library.

You get an error like this:

Duplicate ID "FOO", also in file BAR

Most likely, this means some calendar events were mistakenly retrieved twice (for example, if you ran org-gcal-fetch on different computers). Search your Org-mode files for the duplicate ID “FOO” and delete one of the headlines with duplicate IDs (or just change the ID property on one of the events to something else).

dengste/org-caldav