Andrea-Scuderi

import Cocoa
import Foundation

let baseURL = "http://localhost:8080"

enum APIError: Error {
    case invalidBody
    case invalidEndpoint
    case invalidURL
    case emptyData

Andrea-Scuderi

import Combine

// With Combine we return a DataTaskPublisher instead of using the completion handler of the DataTask
func postUser(user: User) throws -> URLSession.DataTaskPublisher {
    let headers = [
        "Content-Type": "application/json",
        "cache-control": "no-cache",
    ]
    let encoder = JSONEncoder()
    guard let postData = try? encoder.encode(user) else {

Andrea-Scuderi

// In a real world App we want to decode our JSON data response into a Codable Object

struct CreateUserResponse: Codable {
    let id: Int
    let email: String
    let name: String
}


// Decoding CreateUserResponse inside a DataTask API client

Andrea-Scuderi

// Refactoring of the URLRequest with dataTask avoiding Throws using fatalError
func buildCreateUserURLRequest(user: User) -> URLRequest {
    let headers = [
        "Content-Type": "application/json",
        "cache-control": "no-cache",
    ]
    let encoder = JSONEncoder()
    guard let postData = try? encoder.encode(user) else {
        fatalError("APIError.invalidBody")
    }

Andrea-Scuderi

//Login
func buildLoginRequest(email: String, password: String) throws -> URLRequest {
    
    
    let loginString = String(format: "%@:%@", email, password)
    let loginData: Data = loginString.data(using: .utf8)!
    let base64LoginString = loginData.base64EncodedString()
    
    let headers = [
        "Content-Type": "application/json",

Andrea-Scuderi

// Completing the API with Combine and dataTaskPublisher

// POST - Login
func buildLoginRequest(email: String, password: String) -> URLRequest {
    
    
    let loginString = String(format: "%@:%@", email, password)
    let loginData: Data = loginString.data(using: .utf8)!
    let base64LoginString = loginData.base64EncodedString()
    

Andrea-Scuderi

//Let's use our brand new Publishers

let todoList = [Todo(id: nil, title: "Learn Composite"),
                Todo(id: nil, title: "Learn SwiftUI")]


// use login to get the Bearer Token
let cancellableLogin = login(email: "user2@example.com", password: "password2")
    .sink(receiveCompletion: { (completion) in
        switch completion {

Andrea-Scuderi

// Use of the dataTaskPublisher API to implement Publisher with the decoded data
struct Token: Codable {
    let string: String
}

// We'll use the following function to validate our dataTaskPublisher output in the pipeline
func validate(_ data: Data, _ response: URLResponse) throws -> Data {
    guard let httpResponse = response as? HTTPURLResponse else {
        throw APIError.invalidResponse
    }

Andrea-Scuderi

// Combining login and postTodo in a single call
func post(email: String, password: String, todo: Todo) -> AnyPublisher<Todo, Error>? {
    return login(email: email, password: password)
        .map {  token -> String in
            return token.string
        }
        .flatMap { (token) -> AnyPublisher<Todo, Error> in
            return postTodo(authToken: token, todo: todoList[1])
        }
        .eraseToAnyPublisher()

Andrea-Scuderi

import Combine
import Foundation

enum APIError: Error {
    case invalidBody
    case invalidEndpoint
    case invalidURL
    case emptyData
    case invalidJSON
    case invalidResponse