Sensing and sending data to online services

In this section, we shall make use of an online service called Xively; the service allows us to connect, transmit, and view data online. Xively makes use of a common protocol that is used for transferring information over HTTP called REpresentational State Transfer (REST). REST is used by many services, such as Facebook and Twitter, using various keys and access tokens to ensure data is transferred securely between authorized applications and verified sites.

You can perform most REST operations (methods such as POST, GET, SET, and so on) manually using a Python library called requests (http://docs.python-requests.org).

However, it is often easier to make use of specific libraries available for the service you intend to use. They will handle the authorization process; provide access functions; and, if the service changes, the library can be updated rather than your code.

We will use the xively-python library, which provides Python functions to allow...