Networking & REST API

Darsliklar (Tutorials)

Networking & REST API — To'liq Darslik

Mundarija

1. Nega Networking kerak? (Motivatsiya)
2. HTTP Asoslari
3. URLSession Asoslari
4. Codable — JSON Parsing
5. Async/Await bilan Networking
6. Error Handling (Xatolarni boshqarish)
7. Pagination (Sahifaviy yuklash)
8. Image Loading & Caching
9. Network Layer Arxitekturasi
10. Interceptors & Middleware
11. URLSession vs Alamofire
12. Xulosa va keyingi qadamlar

1. Nega Networking kerak? (Motivatsiya) {#motivatsiya}

Deyarli har bir zamonaviy iOS ilovasi internetga ulangan bo'lishi kerak. Nega?

• Ma'lumotlar almashinuvi: Foydalanuvchi profilini yuklash, postlar ko'rish, xabar yuborish.
• Server-side logic: Og'ir hisob-kitoblar yoki sun'iy intellekt amallarini serverda bajarish.
• Real-time yangilanishlar: Ob-havo, valyuta kurslari yoki yangiliklarni doimiy ravishda yangilab turish.

Networking bo'lmasaydi, ilovalar shunchaki "o'lik" ma'lumotlar ombori bo'lib qolardi.

2. HTTP Asoslari {#http-asoslari}

Server bilan muloqot qilishning asosiy tili — HTTP (HyperText Transfer Protocol).

Metodlar:

• GET: Ma'lumotni o'qish (masalan, feed'ni ko'rish).
• POST: Yangi ma'lumot yaratish (masalan, yangi akkaunt ochish).
• PUT: Bor ma'lumotni to'liq yangilash.
• PATCH: Ma'lumotning bir qismini o'zgartirish.
• DELETE: Ma'lumotni o'chirish.

Status Code'lar:

• 200-299: Muvaffaqiyat (Success).
• 400-499: Mijoz xatosi (Client Error — masalan, 404 Not Found).
• 500-599: Server xatosi (Server Error).

3. URLSession Asoslari {#urlsession-asoslari}

Apple'ning networking uchun asosiy quroli — URLSession.

// Eng oddiy GET so'rov
func fetchSimpleData() {
    guard let url = URL(string: "https://api.example.com/data") else { return }
    
    let task = URLSession.shared.dataTask(with: url) { data, response, error in
        if let error = error {
            print("Xato: \(error)")
            return
        }
        
        if let data = data {
            print("Ma'lumot keldi: \(data.count) bytes")
        }
    }
    task.resume() // Bu buyruq so'rovni boshlaydi!
}

4. Codable — JSON Parsing {#codable}

Serverdan ma'lumotlar ko'pincha JSON formatida keladi. Ularni Swift obyektlariga o'tkazish uchun Codable ishlatiladi.

struct User: Codable {
    let id: Int
    let name: String
    let email: String
    
    // Agar JSON dagi nom boshqacha bo'lsa:
    enum CodingKeys: String, CodingKey {
        case id
        case name = "full_name"
        case email
    }
}

// Dekodlash (JSON -> Object)
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase // optional
let user = try decoder.decode(User.self, from: jsonData)

5. Async/Await bilan Networking {#async-await}

iOS 15 dan boshlab networking ancha toza ko'rinishga keldi.

func fetchUsers() async throws -> [User] {
    let url = URL(string: "https://api.example.com/users")!
    
    // Async so'rov
    let (data, response) = try await URLSession.shared.data(from: url)
    
    // Status kodni tekshirish
    guard let httpResponse = response as? HTTPURLResponse,
          (200...299).contains(httpResponse.statusCode) else {
        throw NetworkError.invalidResponse
    }
    
    return try JSONDecoder().decode([User].self, from: data)
}

6. Error Handling (Xatolarni boshqarish) {#error-handling}

Professional ilovada xatolarni foydalanuvchiga tushunarli qilib ko'rsatish kerak.

enum NetworkError: Error, LocalizedError {
    case invalidURL
    case invalidResponse
    case decodingError
    case serverError(String)
    
    var errorDescription: String? {
        switch self {
        case .invalidURL: return "URL noto'g'ri."
        case .invalidResponse: return "Serverdan xato javob keldi."
        case .decodingError: return "Ma'lumotni o'qishda xato."
        case .serverError(let msg): return "Server xatosi: \(msg)"
        }
    }
}

7. Pagination (Sahifaviy yuklash) {#pagination}

Minglab postlarni birdaniga yuklash xotirani to'ldirib yuboradi. Shuning uchun sahifalab yuklanadi.

1. Offset-based: limit=20&offset=0, keyin offset=20...
2. Cursor-based: next_cursor=abc123. Xavfsizroq va tezroq.

8. Image Loading & Caching {#image-loading}

Internetdan rasmlarni yuklash og'ir amal. Ularni keshlab qo'yish shart.

// SwiftUI AsyncImage
AsyncImage(url: URL(string: "https://example.com/img.jpg")) { image in
    image.resizable().scaledToFit()
} placeholder: {
    ProgressView()
}

Ilg'or loyihalarda NSCache yoki SDWebImage / Kingfisher ishlatish tavsiya etiladi.

9. Network Layer Arxitekturasi {#network-architecture}

Kodni har doim modullarga bo'ling. Protocol-based yondashuv test qilishni osonlashtiradi.

protocol APIClient {
    func request<T: Decodable>(_ endpoint: Endpoint) async throws -> T
}

enum Endpoint {
    case getUsers
    case getPost(id: Int)
    
    var path: String {
        switch self {
        case .getUsers: return "/users"
        case .getPost(let id): return "/posts/\(id)"
        }
    }
}

10. Interceptors & Middleware {#interceptors}

Har bir so'rovga "Auth Token" qo'shish yoki 401 (Unauthorized) bo'lganda tokenni yangilash (refresh token) uchun ishlatiladi.

11. URLSession vs Alamofire {#urlsession-vs-alamofire}

Tavsiya: Kichik va o'rta loyihalar uchun Native URLSession kuchi yetarli. Murakkab fayl yuklamalari bo'lsa Alamofire yaxshi tanlov.

12. Xulosa va keyingi qadamlar {#xulosa}

Siz hozirgina zamonaviy iOS networking asoslarini o'rgandingiz. Keyingi qadamlar:

1. Birorta bepul API (masalan, JSONPlaceholder) bilan kichik loyiha qilib ko'ring.
2. async/await va Codable dan foydalaning.
3. Xatolarni chiroyli tarzda Alert yoki Toast orqali ko'rsatishni mashq qiling.

Muvaffaqiyatlar! 🚀