This chapter covers
In this chapter, we’ll cover the data structures and concepts necessary to build a system that offers almost all of the back-end-level functionality of Twitter. This chapter isn’t intended to allow you to build a site that scales to the extent of Twitter, but the methods that we cover should give you a much better understanding of how social networking sites can be built from simple structures and data.
We’ll begin this chapter by talking about user and status objects, which are the basis of almost all of the information in our application. From there, we’ll discuss the home timeline and followers/following lists, which are sequences of status messages or users. Continuing on, we’ll work through posting status messages, following/unfollowing someone, and deleting posts, which involves manipulating those lists. Finally, we’ll build out a fully functioning streaming API with web server to encourage users of the social network to use and play with the data.
In the last chapter, we spent much of our time building an ad-targeting engine that combined user-entered data (the ads and their prices) with click behavior data in order to optimize ad earnings. The ad-targeting engine was query-intensive, in that every request could cause a lot of computation. In this Twitter-like platform, we’ll do our best to perform as little work as possible when someone is interested in viewing a page.
To get started, let’s build the basic structures that will hold much of the data that our users are interested in.
