MongoDB Applied Design Patterns

Chapter 8. Social Networking

In this chapter, we’ll explore how you could use MongoDB to store the social graph for a social networking site. We’ll look at storing and grouping followers as well as how to publish events to different followers with different privacy settings.

Solution Overview

Our solution assumes a directed social graph where a user can choose whether or not to follow another user. Additionally, the user can designate “circles” of users with which to share updates, in order to facilitate fine-grained control of privacy. The solution presented here is designed in such a way as to minimize the number of documents that must be loaded in order to display any given page, even at the expense of complicating updates.

The particulars of what type of data we want to host on a social network obviously depend on the type of social network we’re designing, and is largely beyond the scope of this use case. In particular, the main variables that you would have to consider in adapting this use case to your particular situation are:

What data should be in a user profile?

This may include gender, age, interests, relationship status, and so on for a “personal” social network, or may include resume-type data for a more “business-oriented” social network.

What type of updates are allowed?

Again, depending on what flavor of social network you are designing, you may wish to allow posts such as status updates, photos, links, check-ins, and polls, or you may wish to restrict your users ...