URLSessionDecodable

A swift package for adding decoding functionality to URLSession. It is a very small but handful library, that solves the common pattern of deserialization of a response, and fallback on another message format in case of an HTTP error.

We have been using it in some form over the years at former Viacom, now Paramount. Since Swift Package Manager support in Xcode 11.0, we use it on production in several projects.

Installation

Swift Package Manager

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/ViacomInc/URLSessionDecodable.git", .upToNextMajor(from: "0.1.0"))
]

Usage

Example usage, fetching a response that has a specific error format if error is handled by a backend:

struct AnimalsResponse: Decodable {
    let name: String
}

struct AnimalsError: Error {
    // optional, there are also other errors than the ones handled by a backend 
    let errorResponse: ErrorResponse? 
}

struct ErrorResponse: Decodable {
    let userMessage: String
}

func getFavoriteAnimals(urlSession: URLSession = .shared,
                        completionHandler: (Result<AnimalsResponse, AnimalsError>) -> Void) -> Cancelable {
	
	let url = URL(string: "https://myservice.com/favoriteAnimals")!
	return urlSession.decodableTask(with: url,
	                                method: .get,
	                                parameters: nil,
	                                headers: nil,
	                                decoder: JSONDecoder()) { result in
	    
	    switch result {
	    	case .success(let animals):
	    	   completionHandler(.success(animals))
	    	case .failure(let error):
	    	   let animalsFetchError: ErrorResponse? = error.decodeResponse(using: JSONDecoder())
	    	   completionHandler(.failure(AnimalsError(errorResponse: animalsFetchError)))
	    }
	}
}

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

License

URLSessionDecodable is released under the Apache 2.0 license. See LICENSE for details.