Introduction to APIs

Sam Maurer
Guest lecture for UC Berkeley CP255 Urban Informatics
October 9, 2017

This demo introduces APIs, which are code-based interfaces that allow outside developers to interact with a piece of software. We'll focus primarily on data-access APIs that operate over the web. In class we'll use Python to connect to a variety of APIs, from earthquake feeds and geocoders to public social media posts.

Before class

1. Save the demo files to your computer

2. From the command line, install this Python package for connecting to Twitter APIs:
   pip install TwitterAPI

   There are several different package managers for Python. We're using "pip install" instead of "conda install" because Conda doesn't include this package in its index.

If not enrolled in the class

3. Sign up for Twitter API credentials (5 minutes)

   The latter part of the demo requires free Twitter API credentials. Rename keys-example.py to keys.py and follow these instructions:

   • Log into Twitter or create an account: http://twitter.com

   • Register a new developer project: https://dev.twitter.com/apps/new

     (The form is geared toward people making smartphone apps or web apps, but you still have to fill it out... You can call the app a learning exercise and give the URL of these demo instructions, for example)

   • Submit the form, go to the "Keys and Access Tokens" tab, and click on "Create my access token" at the bottom of the page

   • Copy these four codes into the keys.py file:
     (a) consumer key, (b) consumer secret, (c) access token, (d) access token secret