Swift:
Envoi d'une requête HTTP avec authentification de base

import Foundation

let username = "user"
let password = "pass"
let loginString = String(format: "%@:%@", username, password)
let loginData = loginString.data(using: String.Encoding.utf8)!
let base64LoginString = loginData.base64EncodedString()

var request = URLRequest(url: URL(string: "https://example.com/api/data")!)
request.httpMethod = "GET"
request.setValue("Basic \(base64LoginString)", forHTTPHeaderField: "Authorization")

let session = URLSession.shared
session.dataTask(with: request) { data, response, error in
    guard let data = data, error == nil else {
        print(error?.localizedDescription ?? "No data")
        return
    }
    if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {
        print("StatusCode should be 200, but is \(httpStatus.statusCode)")
        print("Response = \(response!)")
    }
    let responseData = String(data: data, encoding: .utf8)
    print("ResponseData: \(responseData!)")
}.resume()