Depricated google endpoint - new endpoint doesn't work

[wentasah]

Hello,

https://developers.google.com/google-apps/calendar/caldav/v2/guide says that https://www.google.com/calendar/dav endpoint is deprecated. One should use https://apidata.googleusercontent.com/caldav/v2/calid/events instead. I tried to

(setq org-caldav-url "https://apidata.googleusercontent.com/caldav/v2")

and modified the source like this:

diff --git a/org-caldav.el b/org-caldav.el
index cccb9bf..7241a26 100644
--- a/org-caldav.el
+++ b/org-caldav.el
@@ -322,7 +322,7 @@ Are you really sure? ")))
 
 (defun org-caldav-events-url ()
   "Return URL for events."
-  (if (string-match "google\\.com" org-caldav-url)
+  (if (string-match "google\\(usercontent\\)?\\.com" org-caldav-url)
       (concat org-caldav-url "/" org-caldav-calendar-id "/events/")
     (concat org-caldav-url "/" org-caldav-calendar-id "/")))
 

I ended up with an error:

Debugger entered--Lisp error: (wrong-type-argument char-or-string-p nil)
  url-http-handle-authentication(nil)
  url-http-parse-headers()
  url-http-chunked-encoding-after-change-function(415 440 25)
  url-http-wait-for-headers-change-function(1 453 452)
  url-http-generic-filter(# "HTTP/1.1 401 Unauthorized
\nWWW-Authenticate: Bearer realm=\"https://www.google.com/accounts/AuthSubRequest\"
\nContent-Type: text/html; charset=UTF-8
\nDate: Tue, 24 Sep 2013 13:32:04 GMT
\nExpires: Tue, 24 Sep 2013 13:32:04 GMT
\nCache-Control: private, max-age=0
\nX-Content-Type-Options: nosniff
\nX-Frame-Options: SAMEORIGIN
\nX-XSS-Protection: 1; mode=block
\nServer: GSE
\nAlternate-Protocol: 443:quic
\nTransfer-Encoding: chunked
\n
\ne
\nLogin Required
\n0
\n
\n")
  accept-process-output(#)
  #[0 "\302�\303\300@!)\207" [(#) inhibit-quit nil accept-process-output] 2 "\n\n(fn)"]()
  funcall(#[0 "\302�\303\300@!)\207" [(#) inhibit-quit nil accept-process-output] 2 "\n\n(fn)"])
  url-retrieve-synchronously("https://apidata.googleusercontent.com/caldav/v2/wentasah@gmail.com/events/")
  url-http-options("https://apidata.googleusercontent.com/caldav/v2/wentasah@gmail.com/events/")
  url-dav-supported-p("https://apidata.googleusercontent.com/caldav/v2/wentasah@gmail.com/events/")
  (if (url-dav-supported-p (org-caldav-events-url)) nil (error "The URL %s does not seem to accept DAV requests" (org-caldav-events-url)))
  org-caldav-sync()
  call-interactively(org-caldav-sync record nil)
  command-execute(org-caldav-sync record)
  execute-extended-command(nil "org-caldav-sync")
  call-interactively(execute-extended-command nil nil)

Any idea why is that? With the old endpoint, everything works.

[dengste]

The new endpoint requires OAuth2 authentication. This is not supported in Emacs proper, though there exists a library for it in GNU ELPA.

I guess I could extend org-caldav to use this library, but after looking around for roughly an hour on Google, using the new endpoint with OAuth2 isn't straightforward at all. It seems I have to register org-caldav as an application, which also for some reason requires giving Google my cell phone number, which I won't do. Also, the application is restricted to limits like 5 requests per second, which will lead to errors during the initial sync. Unless I pay for it, of course...

I find it pretty ridiculous that I should have to jump through hoops like this just to sync a calendar, especially since I don't use it. So it seems that when the old endpoint stops working, this is it for Google Calendar sync, unless someone else wants to implement it.

[d12frosted]

You are not required to create application. It's better to ask users that want to use OAuth2 to create their own applications if they wish to use new endpoint. So 5 requests per second is good enough for almost all users.

As example, there is org-gcal that works with new end point.

[sje30]

Is anyone else interested in merging org-gcal functionality into org-caldav?

[dengste]

Since Google does no longer require cell phone numbers for registering a CalDAV application, I've added that functionality. Every user will still need to register its own application with Google, though (see README).