Chapter 8
Loading and Parsing Network Data

All this time, we’ve sort of been working our podcast app backwards: instead of parsing a feed, finding episodes, and playing one, we started with the player. This gave us a chance to play around with building user interfaces, but now it’s time to do the heavy lifting.

Think about what a podcast app does: it goes out to the network and fetches a list of episodes for one or more podcast feeds. Each of those must contain the metadata (titles, dates, etc.) and a URL for the audio. This metadata is in some structured form—by convention, podcasts use XML with a specific set of tags—so the client needs to parse this data, looking through the structured data for the parts it needs. From that, it can build a user interface showing the podcast feeds, and let the user interact with it.

In this chapter, our task will be to download a podcast feed from the network, and to parse its contents into a format that’s convenient for our Swift code to work with. We’ll see what the iOS SDKs offer for each of these tasks and what parts we have to handle ourselves.