CombineNetworking

Meet CombineNetworking. Super lightweight and crazy easy to use framework to help you create and handle your network requests in a convenient way. Besides basic network requests, CombineNetworking allows you to easily send your requests securely with a simple SSL and Certificate pinning mechanisms. But that’s not all. With CombineNetworking you can also effortlessly handle authorization tokens with built-in automatic authorization mechanism.

Installation (using CocoaPods)

pod 'CombineNetworking'

Note that in order to use CombineNetworking, your iOS Deployment Target has to be 13.0 or newer. If you code for macOS, your Deployment Target has to be 10.15 or newer.

CombineNetworking is also available via SPM (Swift Package Manager)

Key functionalities

• Sending requests easily using Endpoint models
• SSL and Certificate pinning with just 2 lines of code
• WebSocket connection support with CNWebSocket
• Secure access token storage with Keychain
• Access token storing strategy - configure global, endpoint specific (default) or custom strategy for all or just some endpoints
• Automated refresh token/callback requests

Basic Usage

Create an Endpoint to work with

enum TodosEndpoint {
    case todos(Int)
}

extension TodosEndpoint: Endpoint {
    var baseURL: URL? {
        URL(string: "https://jsonplaceholder.typicode.com/")
    }
    
    var path: String {
        switch self {
        case .todos:
            return "todos"
        }
    }
    
    var method: RequestMethod {
        .get
    }
    
    var headers: [String : Any]? {
        nil
    }
    
    var data: EndpointData {
        switch self {
        case .todos(let id):
            return .queryParams(["id": id])
        }
    }
}

RequestMethod is an enum with following options: .get, .post, .put, .delete, patch. EndpointData is also an enum with following options:

• .plain
• .queryParams([String: Any])
• .queryString(String)
• .bodyData(Data)
• .bodyParams([String: Any]) - takes Dictionary and parses it into Data to send in request’s body
• .urlEncodedBody([String: Any]) - takes Dictionary and parses it into url encoded Data to send in request’s body
• .urlEncodedModel(Encodable) - takes Encodable model and parses it into url encoded Data to send in request’s body
• .jsonModel(Encodable) - similar to .dataParams except this one takes Encodable and parses it into Data to send in request’s body

Enable SSL and/or Certificate pinning (optional)

To turn SSL and/or Certificate pinning in your app just add:

CNConfig.pinningModes = [.ssl, .certificate]

Please remember that SSL/Certificate pinning requires certificate file to be attached in your project. Certificates and SSL keys are autmatically loaded by CombineNetworking.

Automatic authorization mechanism

Handling authorization callbacks with CombineNetworking is ridiculously easy. To use it with your Endpoint all you have to do is to add requiresAccessToken and callbackPublisher fields as presented below:

enum TodosEndpoint {
    case token
    case todos(Int)
}

extension TodosEndpoint: Endpoint {
    //Setup all the required properties like baseURL, path, etc...
        
    //... then determine which of your endpoints require authorization...
    var requiresAccessToken: Bool {
        switch self {
        case .token:
            return false
     
        default:
            return true
        }
    }
    
    //... and prepare callbackPublisher to handle authorization callbacks
    var callbackPublisher: AnyPublisher<AccessTokenConvertible?, Error>? {
        try? CNProvider<TodosEndpoint>().publisher(for: .token, responseType: CNAccessToken?.self).asAccessTokenConvertible()
    }
}

See? Easy peasy! Keep in mind that your token model has to conform to AccessTokenConvertible.

CNConfig properties and methods

• pinningModes - turns on/off SSL and Certificate pinning. Available options are .ssl, .certificate or both.
• sitesExcludedFromPinning - list of website addresses excluded from SSL/Certificate pinning check
• defaultJSONDecoder - use this property to set globally your custom JSONDecoder
• defaultAccessTokenStrategy - global strategy for storing access tokens. Available options are .global, .default and .custom(String).
• keychainInstance - keychain instance used by CombineNetworking to store/fetch access tokens from Apple’s Keychain. If not provided, safe storage will be turned off (more info below)

Access Token Strategies

CombineNetworking allows you to specify access token strategies globally as well as individually for each endpoint. You can specify your strategy by setting it for CNConfig.defaultAccessTokenStrategy or inside your Endpoint by setting value for field accessTokenStrategy. Available options are:

• .global - uses global label to store access token
• .default - uses endpoint identifiers as labels to store access tokens
• .custom(String) - with this option you can specify your own label to store access token and use it among as many endpoints as you wish

Thanks to access token strategy being set both globally (via CNConfig) and individually (inside Endpoint), you can mix different strategies in your app!

Access Token manipulations

If you want, you can manipulate access tokens yourself. There are 4 approaches how to store, fetch and remove access tokens using CNConfig.

1. For specific endpoint:

• setAccessToken(_ token: CNAccessToken?, for endpoint: Endpoint)
• accessToken(for endpoint: Endpoint)
• removeAccessToken(for endpoint: Endpoint)

Example: CNConfig.accessToken(for: .sampleEndpointCase)

2. For specific endpoint’s default storing label:

• setAccessToken<T: Endpoint>(_ token: CNAccessToken?, for endpoint: T.Type)
• accessToken<T: Endpoint>(for endpoint: T.Type)
• removeAccessToken<T: Endpoint>(for endpoint: T.Type)

Example: CNConfig.accessToken(for: SampleEndpoint.self)

3. For specific custom storing label:

• setAccessToken(for storingLabel: String)
• accessToken(for storingLabel: String)
• removeAccessToken(for storingLabel: String)

Example: CNConfig.accessToken(for: "sampleCustomLabel")

4. For global tokens:

• setGlobalAccessToken()
• globalAccessToken()
• removeGlobalAccessToken()

Example: CNConfig.globalAccessToken()

Event logging

CombineNetworking’s CNProvider uses iOS built-in Logger (if running on iOS 14 or newer) and custom debug-mode-only logger by default for each and every request.

Network connection monitor

CombineNetowrking allows you continuously monitor network connection status. If you want to subscribe to a network connection monitor’s publisher, you can do it like this:

private var subscriptions: Set<AnyCancellable> = []

func subscribeForNetworkChanges() {
    CNNetworkMonitor.publisher()
        .sink { status in
            switch status {
            case .wifi:
                // Do something
            case .cellular:
                // Do something else
            case .unavailable:
                // Show connection error
            }
        }
        .store(in: &subscriptions)
}

Safe storage using Keychain

CombineNetworking allows you to store your access tokens in keychain. Using keychain to store your access tokens requires you to provide keychain instance by setting value of CNConfig.keychainInstance.

Please remember Apple’s Keychain doesn’t automatically remove entries created by an app upon its deletion. Do not worry, however. Only your app can access those entries, nevertheless, it’s up to you to make sure those are removed from keychain if not needed anymore. CombineNetworking provides method CNConfig.removeAccessToken(...) to help you do it.

Subscribe to a publisher

private var subscriptions: Set<AnyCancellable> = []
var todo: Todo?

func subscribeForTodos() {
    CNProvider<TodosEndpoint>().publisher(for: .todos(1), responseType: Todo?.self)
        .catch { (error) -> Just<Todo?> in
            print(error)
            return Just(nil)
        }
        .assign(to: \.todo, on: self)
        .store(in: &subscriptions)
}

If you want to subscribe to a publisher but doesn’t want to immediately decode the body but rather want to get raw Data object, use rawPublisher instead.

Error handling

In case of request failure, CombineNetworking returns stuct of type CNError reflected as Error.

public struct CNError: Error {
    let type: ErrorType
    let details: CNErrorDetails?
    let data: Data?
}

Available error types are: failedToBuildRequest, failedToMapResponse, unexpectedResponse, authenticationFailed, notConnected, emptyResponse, noInternetConnection and conversionFailed.

CNErrorDetails looks like following:

public struct CNErrorDetails {
    public let statusCode: Int
    public let localizedString: String
    public let url: URL?
    public let mimeType: String?
    public let headers: [AnyHashable: Any]?
    public let data: Data?
}

Simplified testing

If you want to run simple tests on your request, just to confirm the status code of the response met the expectations set for a given endpoint you can just run testRaw() method like this:

final class CombineNetworkingTests: XCTestCase {
    private let provider = CNProvider<RemoteEndpoint>()
    
    func testTodoFetch() throws {
        let expectation = expectation(description: "Test todo fetching request")
    var subscriptions: Set<AnyCancellable> = []
        
    provider.testRaw(.todos, usingMocks: false, storeIn: &subscriptions) {
        expectation.fulfill()
    }
        
        wait(for: [expectation], timeout: 10)
    } 
}

… and if you want to test your request by confirming both the status code and the response model, use test() method like this:

final class CombineNetworkingTests: XCTestCase {
    private let provider = CNProvider<RemoteEndpoint>()
    
    func testTodoFetchWithModel() throws {
        let expectation = expectation(description: "Test todo fetching request together with its response model")
    var subscriptions: Set<AnyCancellable> = []
        
    provider.test(.todos, responseType: Todo.self, usingMocks: false, storeIn: &subscriptions) {
        expectation.fulfill()
    }
        
        wait(for: [expectation], timeout: 10)
    } 
}

You can also use mocked data in your tests. To do so, just add mockedData to your Endpoint and when calling provider.test() or provider.testRaw() set usingMocks to true.

WebSockets

CombineNetworking also allows you to connect with WebSockets effortlessly. Simply use CNWebSocket like this:

let webSocket = CNWebSocket(url: URL(string: "wss://socketsbay.com/wss/v2/2/demo/")!)
webSocket.connect()
webSocket.listen { result in
    switch result {
    case .success(let message):
        switch message {
    case .data(let data):
        print("Received binary: \(data)")
    case .string(let string):
        print("Received string: \(string)")
    }
    default:
    return
    }
}

webSocket.send(.string("Test message")) {
    if let error = $0 {
        log(error.localizedDescription)
    }
}

If you want to close connection, just call webSocket.disconnect().

And that’s it. Enjoy :)