An extremely lightweight wrapper around URLSession to make working with APIs a breeze.
Hyperspace provides a simple abstraction around URLSession and HTTP. There are a few main goals:
HTTP
definitions), but our main goal is to keep the library highly functional and maintainable without over-engineering.URLRequest
, utilizing the definitions in HTTP
.TransportSession
(URLSession
by default) to execute URLRequests
. Deals with raw HTTP
and Data
.TransportService
to execute Requests
. Transforms the raw Data
returned from the TransportService
into the response model type defined by the Request
. This is the main worker object your app will deal with directly.You have multiple options when creating requests. These include creating static functions to reduce the boilerplate when creating a Request
object or simply creating them locally. In addition, you can still create your own custom struct that wraps and vends a Request
object if your network requests are complex.
Request
The example below illustrates how to create an extension on Request
which can drastically reduce the boilerplate when creating a request to create a new post in something like a social network feed. It takes advantage of the many defaults into Request
(all of which are customizable) to keep the definition brief:
extension Request where Response == Post {
static func createPost(_ post: NewPost) -> Request<Post> {
return Request(method: .post, url: URL(string: "https://jsonplaceholder.typicode.com/posts")!, headers: [.contentType: .applicationJSON], body: try? HTTP.Body.json(post))
}
}
Request
Locallylet createPostRequest: Request<Post> = Request(method: .post, url: URL(string: "https://jsonplaceholder.typicode.com/posts")!, headers: [.contentType: .applicationJSON], body: try? HTTP.Body.json(post))
CreatePostRequest
that wraps a Request
struct CreatePostRequest {
let newPost: NewPost
var request: Request<Post> {
return Request(method: .post, url: URL(string: "https://jsonplaceholder.typicode.com/posts")!, headers: [.contentType: .applicationJSON], body: try? HTTP.Body.json(post))
}
}
For the above examples, the Post
response type and NewPost
body are defined as follows:
struct Post: Decodable {
let id: Int
let userId: Int
let title: String
let body: String
}
struct NewPost: Encodable {
let userId: Int
let title: String
let body: String
}
To avoid having to define default Request
property values for every request in your app, it can be useful to rely on the RequestDefaults
provided by Hyperspace. These can even be customized:
RequestDefaults.defaultCachePolicy = .reloadIgnoringLocalCacheData // Default cache policy is '.useProtocolCachePolicy'
RequestDefaults.defaultDecoder = MyCustomDecoder() // Default decoder is JSONDecoder()
We recommend adhering to the Interface Segregation principle by creating separate "controller" objects for each section of the API you're communicating with. Each controller should expose a set of related functions and use a BackendService
to execute requests. However, for this simple example, we'll just use BackendService
directly as a private
property on the view controller:
class ViewController: UIViewController {
private let backendService = BackendService()
// Rest of your view controller code...
}
Let's say a view controller is supposed to create the post whenever the user taps the "send" button. Here's what that might look like:
@IBAction private func sendButtonTapped(_ sender: UIButton) {
let title = ... // Get the title from a text view in the UI...
let message = ... // Get the message from a text view/field in the UI...
let post = NewPost(userId: 1, title: title, body: message)
let createPostRequest = CreatePostRequest(newPost: post)
// Execute the network request...
}
For the above example, here's how you would execute the request and parse the response. While all data transformation happens on the background queue that the underlying URLSession is using, all BackendService
completion callbacks happen on the main queue so there's no need to worry about threading before you update UI. Notice that the type of the success response's associated value below is a Post
struct as defined in the CreatePostRequest
above:
do {
let post = NewPost(userId: 1, title: title, body: "")
let createPostRequest = Request<Post>.createPost(post)
let createdPost = try await backendService.execute(request: createPostRequest)
// Insert the new post into the UI...
} catch {
// Alert the user to the error...
}
Clone the repo:
git clone https://github.com/BottleRocketStudios/iOS-Hyperspace.git
From here, you can open up Hyperspace.xcworkspace
and run the examples:
Models.swift
, Requests.swift
ViewController.swift
ViewController.swift
InterfaceController.swift
Hyperspace is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod 'Hyperspace'
Add the following to your Cartfile:
github "BottleRocketStudios/iOS-Hyperspace"
Run carthage update
and follow the steps as described in Carthage's README.
dependencies: [
.package(url: "https://github.com/BottleRocketStudios/iOS-Hyperspace.git", from: "5.0.0")
]
Hyperspace is available under the Apache 2.0 license. See the LICENSE.txt file for more info.
See the CONTRIBUTING document. Thank you, contributors!