I have been wanting to write a post for awhile, but was travelling for a work event and while on the road I decided to be lazy.
Since I just so happen to use a few GData APIs occasionally in my day to day work, most of the post ideas revolve around quirky things I have done or want to do with the APIs. Also, due to my obscene love for Python, all my mashups seem to end up using the Python Client for GData.
As I was finalizing travel and gifts for my winter holiday back home, I called an old friend to let him know I'd be home in 40 days. After relaying this information to a few other people, I noted to my girlfriend that it would be nice if a computer would remind me of the count every day. This is where this quick and dirty pair of scripts come in to remind me when Santa is coming.
Pre-work — Account Settings:
To allow an app to make requests on my behalf, I signed up to
Manage my Domain
for use with Google Apps, etc. For illustration purposes, let's say I used
http://example.com (in reality, I used a pre-existing App of mine, I really
just needed an OAuth token for one time use, no real safety concerns there).
After adding this domain in the management page, I am able to get my
OAuth Consumer Key and OAuth Consumer Secret which we'll say are
EXAMPLE_SECRET in this example. Also in the management page,
I set my OAuth 2.0 Redirect URIs and made sure my app can serve that page
(even if it is a 404). Again for illustration, let's pretend I used
After doing this settings pre-work, I have two scripts to do the work for me.
First script — get the OAuth Token:
import gdata.calendar.client import gdata.gauth gcal = gdata.calendar.client.CalendarClient() oauth_callback = 'http://example.com/verify' scopes = ['https://www.google.com/calendar/feeds/'] consumer_key = 'EXAMPLE_KEY' consumer_secret = 'EXAMPLE_SECRET' request_token = gcal.get_oauth_token(scopes, oauth_callback, consumer_key, consumer_secret) out_str = ('Please visit https://www.google.com/accounts/OAuthAuthorize' 'Token?hd=default&oauth_token=%s' % request_token.token) print out_str follow = raw_input('Please entry the follow link after authorizing:\n') gdata.gauth.authorize_request_token(request_token, follow) gcal.auth_token = gcal.get_access_token(request_token) print 'TOKEN:', gcal.auth_token.token print 'TOKEN_SECRET:', gcal.auth_token.token_secret
This script "spoofs" the OAuth handshake by asking the user (me) to go
directly to the
OAuth Authorize page.
After doing so and authorizing the App, I am redirected to
http://example.com/verify with query parameters for
oauth_token. These are then used by the
section of the GData library to finish the OAuth handshake. Once the
handshake is complete, the script prints out a necessary token and token
secret to be used by the second script. I would advise piping the output
to a file, augmenting the script to write them to a file, or writing
these down (this is a joke, please don't write down 40 plus character
goop that was produced by your computer). For the next script,
let's pretend our token is
FAKE_TOKEN and our token secret is
Second script — insert the events:
# General libraries from datetime import date from datetime import timedelta # Third-party libraries import atom import gdata.gauth import gdata.calendar.client import gdata.calendar.data gcal = gdata.calendar.client.CalendarClient() auth_token = gdata.gauth.OAuthHmacToken(consumer_key='EXAMPLE_KEY', consumer_secret='EXAMPLE_SECRET', token='FAKE_TOKEN', token_secret='FAKE_TOKEN_SECRET', auth_state=3) gcal.auth_token = auth_token today = date.today() days_left = (date(year=2011, month=12, day=23) - today).days while days_left >= 0: event = gdata.calendar.data.CalendarEventEntry() if days_left > 1: msg = '%s Days Until Home for Christmas' % days_left elif days_left == 1: msg = '1 Day Until Home for Christmas' elif days_left == 0: msg = 'Going Home for Christmas' event.title = atom.data.Title(msg) # When start_time = '2011-%02d-%02dT08:00:00.000-08:00' % (today.month, today.day) end_time = '2011-%02d-%02dT09:00:00.000-08:00' % (today.month, today.day) event.when.append(gdata.calendar.data.When( start=start_time, end=end_time, reminder=[gdata.data.Reminder(hours='1')])) gcal.InsertEvent(event) today += timedelta(days=1) days_left -= 1
This script first authenticates by using the key/secret pair for the
application (retrieved from the settings page) and the key/secret pair
for the user token (that we obtained from the first script). To
authenticate, we explicitly construct an HMAC-SHA1 signed token in the
final auth state (3) of two-legged OAuth and then set the token on our
calendar client (
After authenticating, we start with today and figure out the number of
days in the countdown given my return date of December 23, 2011. With
these in hand, we can loop through until there are no days left,
CalendarEventEntry with title as the number of days left
in the countdown and occurring from 8am to 9am PST (UTC -8). Notice also
I include a
gdata.data.Reminder so I get an email at 7am every morning
(60 minutes before the event) updating my brain on the length of the
Be sure to go to your
issued tokens page
and revoke access to the App (e.g.
after doing this to avoid any unwanted security issues.
I have never read this, but I'm sure the documentation on Registration for Web-Based Applications is very helpful.
You can annoy other people by inviting them to these events for them as well. To do so, simply add the following two lines before inserting the event
who_add = gdata.calendar.data.EventWho(email='[email protected]')event.who.append(who_add)
Sometimes inserting an item results in a RedirectError, so it may be safer to try the insert multiple times with a helper function such as the following:
def try_insert(attempts, gcal, event): from time import sleep from gdata.client import RedirectError while attempts > 0: try: gcal.InsertEvent(event) break except RedirectError: attempts -= 1 sleep(3) if attempts == 0: print 'Insert "%s" failed' % event.title.text