Moya: A Swift repository from aaroncrespo

You're a smart developer. You probably use Alamofire to abstract away access to NSURLSession and all those nasty details you don't really care about. But then, like lots of smart developers, you write ad hoc network abstraction layers. They are probably called "APIManager" or "NetworkModel", and probably look something like this.

It's leaky, meaning your app touches Alamofire directly and your layer bypasses Alamofire to access the network directly sometimes.

This kind of ad hoc network layer is common in iOS apps. It's bad for a few reasons:

It makes it hard to write new apps ("where do I begin?")
It makes it hard to maintain existing apps ("oh my god, this mess...")
It makes it hard to write unit tests ("how do I do this again?")

So the basic idea is that we want some network abstraction layer that sufficiently encapsulates actually calling Alamofire directly. It should be simple enough that common things are easy, but comprehensive enough that complicated things are also easy.

Basically:

If you use Alamofire to abstract away NSURLSession, why not use something to abstract away the nitty gritty of URLs, parameters, etc?

Some awesome features of Moya:

Compile-time checking for correct API endpoint accesses.
Lets you define a clear usage of different endpoints with associated enum values.
Treats test stubs as first-class citizens so unit testing is super-easy.

Sample Project

There's a sample project in the Demo directory. Have fun!

Project Status

This project is actively under development, and is being used in Artsy's new auction app. We consider it ready for production use.

Currently, we support Xcode 7 and Swift 2.

Installation

Cocoapods

Just add pod 'Moya' to your Podfile and go!

In any file you'd like to use Moya in, don't forget to import the framework with import Moya.

For ReactiveCocoa extensions, this project has some dependencies. Add the following lines to your Podfile:

pod 'Moya/ReactiveCocoa'

Then run pod install.

For RxSwift extensions, use the following Podfile.

pod 'Moya/RxSwift'

Carthage

Carthage users can point to this repository and use whichever generated framework they'd like, Moya, RxMoya, or ReactiveMoya. The full Moya framework is bundled in each of those frameworks; importing more than one framework in a single file will result in ambiguous lookups at compile time.

github "Moya/Moya"

Use

After some setup, using Moya is really simple. You can access an API like this:

provider.request(.Zen) { (data, statusCode, response, error) in
    if let data = data {
        // do something with the data
    }
}

That's a basic example. Many API requests need parameters. Moya encodes these into the enum you use to access the endpoint, like this:

provider.request(.UserProfile("ashfurrow")) { (data, statusCode, response, error) in
    if let data = data {
        // do something with the data
    }
}

No more typos in URLs. No more missing parameter values. No more messing with parameter encoding.

For examples, see the documentation.

Reactive Extensions

Even cooler are the reactive extensions. Moya provides reactive extensions for ReactiveCocoa and RxSwift.

ReactiveCocoa

For ReactiveCocoa, it immediately returns a SignalProducer (RACSignal is also available if needed) that you can start or bind or map or whatever you want to do. To handle errors, for instance, we could do the following:

provider.request(.UserProfile("ashfurrow")).start { (event) -> Void in
    switch event {
    case .Next(let response):
        image = UIImage(data: response.data)
    case .Error(let error):
        print(error)
    default:
      break
    }
}

##RxSwift

For RxSwift, it immediately returns an Observable that you can subscribe to or bind or map or whatever you want to do. To handle errors, for instance, we could do the following:

provider.request(.UserProfile("ashfurrow")).subscribe { (event) -> Void in
    switch event {
    case .Next(let response):
        image = UIImage(data: response.data)
    case .Error(let error):
        print(error)
    default:
        break
    }
}

In addition to the option of using signals instead of callback blocks, there are also a series of signal operators for RxSwift and ReactiveCocoa that will attempt to map the data received from the network response into either an image, some JSON, or a string, with mapImage(), mapJSON(), and mapString(), respectively. If the mapping is unsuccessful, you'll get an error on the signal. You also get handy methods for filtering out certain status codes. This means that you can place your code for handling API errors like 400's in the same places as code for handling invalid responses.

Contributing

Hey! Like Moya? Awesome! We could actually really use your help!

Open source isn't just writing code. Moya could use your help with any of the following:

Finding (and reporting!) bugs.
New feature suggestions.
Answering questions on issues.
Documentation improvements.
Reviewing pull requests.
Helping to manage issue priorities.
Fixing bugs/new features.

If any of that sounds cool to you, send a pull request! After a few contributions, we'll add you as an admin to the repo so you can merge pull requests 🎉

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

License

Moya is released under an MIT license. See LICENSE for more information.

aaroncrespo/Moya