Chapter 14 Following users

In this chapter, we will complete the Rails Tutorial sample application by adding a social layer that allows users to follow (and unfollow) other users, resulting in each user’s Home page displaying a status feed of the followed users’ microposts. We’ll start by learning how to model relationships between users in Section 14.1, and we’ll build the corresponding web interface in Section 14.2 (including an introduction to Ajax). We’ll end by developing a fully functional status feed in Section 14.3.

This final chapter contains some of the most challenging material in the tutorial, including some Ruby/SQL trickery to make the status feed. Through these examples, you will see how Rails can handle even rather intricate data models, which should serve you well as you go on to develop your own applications with their own specific requirements. To help with the transition from tutorial to independent development, Section 14.4 offers some pointers to more advanced resources.

Because the material in this chapter is particularly challenging, before writing any code we’ll pause for a moment and take a tour of the interface. As in previous chapters, at this early stage we’ll represent pages using mockups.¹ The full page flow runs as follows: a user (John Calvin) starts at his profile page (Figure 14.1) and navigates to the Users page (Figure 14.2) to select a user to follow. Calvin navigates to the profile of a second user, Thomas Hobbes (Figure 14.3), clicking on the “Follow” button to follow that user. This changes the “Follow” button to “Unfollow” and increments Hobbes’s “followers” count by one (Figure 14.4). Navigating to his home page, Calvin now sees an incremented “following” count and finds Hobbes’s microposts in his status feed (Figure 14.5). The rest of this chapter is dedicated to making this page flow actually work.

Figure 14.1: A current user’s profile.

Figure 14.2: Finding a user to follow.

Figure 14.3: The profile of a user to follow, with a follow button.

Figure 14.4: A profile with an unfollow button and incremented followers count.

Figure 14.5: The Home page with status feed and incremented following count.