SwiftNetworkLayer

SwiftNetworkLayer is an example of writing a minimal networking layer using only native Cocoa Touch APIs in Swift 4.

Features:

1. Create and cancel network requests
2. Load images from the network
3. Present / dismiss LoadingViews while data is loading

I made this example because it seems like most Swift networking layers on GitHub are built atop either Alamofire or Moya. If you're looking to dive deeper into how networking works under the hood, I suggest you try writing your own! Also, if you have ways to make mine better, feel free to submit a pull request :)

About

NetworkService

The NetworkService class has two main functions:

1. request(...), which returns an object conforming to Decodable
2. cancelRequest(...), for cancelling a request

Both methods take an Endpoint as an argument and return a generic Result<T> type, which is declared at the callsite.

Endpoint

An Endpoint contains contains the required URL and URLRequest information to make the network call.

ImageLoader

The ImageLoader has three responsibilities:

1. Fetching an image from the network, provided an image URL
2. Caching a fetched image to memory after it has been retrieved from the network
3. Keeping track of running image network tasks and their callbacks

The ImageLoader (and its sub-components, ImageLoaderCache and ImageLoaderTaskManager) are essential to avoiding redundant network calls and callbacks.

Loadable

Loadable is a protocol which provide methods for presenting and dismissing a LoadingView.

A LoadingView simply contains a loading spinner and a dimmed background.

Example

In the project, there is an Example folder with how SwiftNetworkLayer could be implemented in a project. This example uses the BandsInTown API.

To run the example:

1. Open SwiftNetworkLayer.xcodeproj
2. Press Run (CMD+R)