Building a Simple Birthday App with Flask-SQLAlchemy

One of my favorite Flask extensions is Flask-SQLAlchemy. It makes working with a database a breeze. For some time I wanted to detach my birthday management from Facebook. So I started a simple Flask app. Work so far here.

FB birthday data

I am almost sure you could use the FB API before to pull all your friends and birthdays. Not anymore 🙁

Luckily I found a way to export them and parse them into a useful format – see bdays.py.

Starting Flask-SQLAlchemy

Back to the article subject: how do we get this data into a DB? Flask-SQLAlchemy to the rescue:

• First I defined a simple model in model.py:

  ...
  
  class Birthday(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      name = db.Column(db.String(120))
      bday = db.Column(db.DateTime)
      notify = db.Column(db.Boolean)
  
      def __init__(self, name, bday, notify=False):
          self.name = name
          self.bday = bday
          self.notify = notify
  
      def __repr__(self):
          return '' % (self.name, self.bday, self.notify)
  

  It’s best to store dates as db.DateTime objects so we can easily query them (see further down).

• If model.py is run as standalone script (not imported) it recreates the DB:

  db.drop_all()
  db.create_all()
  

  I use the bdays.py ics parsing code to populate the table with all birthdays. You can even strip out the names (which was useful to share printscreens here). I store all birthdays with the same year (calendar ics ranges May ’17 – May ’18), otherwise the date querying fails (next step):

  # insert birthdays sorted
  for bd in sorted(get_birthdays('cal.ics'), key=lambda x: (x.bday.month, x.bday.day)):
  
      # no real names
      if TEST_MODE:
          name = get_random_name()
      else:
          name = bd.name
  
      # import all bdays with THIS_YEAR to make it easier to query later
      bday = bd.bday.replace(year=THIS_YEAR)
      bd_obj = Birthday(name, bday)
      db.session.add(bd_obj)
  
  db.session.commit()
  

• The app is still very bare-bones. It has an index/home route, to get the birthdays of the next 14 days, and a route to get birthdays for each month. See app.py. Here’s why you want to work with datetime objects, it makes querying dates easier:

  • Upcoming n days:

    @app.route('/')
    ...
    start = datetime.now()
    end = start + timedelta(days=UPCOMING_DAYS)
    bdays = Birthday.query.filter(Birthday.bday <= end).filter(Birthday.bday >= start)
    

  • How to get all birthdays of month n (see SO). The SQLAlchemy query is the same:

    @app.route('/')
    ...
    _, num_days = calendar.monthrange(THIS_YEAR, month)
    start = date(THIS_YEAR, month, 1)
    end = date(THIS_YEAR, month, num_days)
    bdays = Birthday.query.filter(Birthday.bday <= end).filter(Birthday.bday >= start)
    

Resulting App

You can use the calendar module to get the month name for a month int:

month_name = calendar.month_name[month]

See app.py.

TODO

This is it for starters. In part 2 I will make the app more functional:

• Implement notifications: email me one day before a birthday.

• Allow setting of notify == True for individual friends so I only get the notifications I want.

• Full CRUD: add/update/delete friends and/or re-import new ics download.

• Second (relational) model for tracking:

  • add the notifications sent to this table

  • have a “done” flag to update when I sent Happy Birthday wishes to a particular friend.

  This is a nice extension to use Flask-SQLAlchemy’s db.ForeignKey.

Resources

• Flask-SQLAlchemy docs is a great start.

• See our code challenge 15 review for more example apps using Flask-SQLAlchemy.

• For examples of standard SQLAlchemy (outside Flask), our code challenge 17 review has some examples.

• To learn SQLAlchemy start with the Object Relational Tutorial.

Keep Calm and Code in Python!

— Bob