axiom-networking-migration

网络框架迁移指南

我需要迁移吗？

What networking API are you using?

├─ URLSession for HTTP/HTTPS REST APIs?
│   └─ Stay with URLSession — it's the RIGHT tool for HTTP
│      URLSession handles caching, cookies, auth challenges,
│      HTTP/2/3, and is heavily optimized for web APIs.
│      Network.framework is for custom protocols, NOT HTTP.
│
├─ BSD Sockets (socket, connect, send, recv)?
│   └─ Migrate to NWConnection (iOS 12+)
│      → See Migration 1 below
│
├─ NWConnection / NWListener?
│   ├─ Need async/await? → Migrate to NetworkConnection (iOS 26+)
│   │   → See Migration 2 below
│   └─ Callback-based code working fine? → Stay (not deprecated)
│
├─ URLSession StreamTask for TCP/TLS?
│   └─ Need UDP or custom protocols? → NetworkConnection
│      Need just TCP/TLS for HTTP? → Stay with URLSession
│      → See Migration 3 below
│
├─ SCNetworkReachability?
│   └─ DEPRECATED — Replace with NWPathMonitor (iOS 12+)
│      let monitor = NWPathMonitor()
│      monitor.pathUpdateHandler = { path in
│          print(path.status == .satisfied ? "Online" : "Offline")
│      }
│
└─ CFSocket / NSStream?
    └─ DEPRECATED — Replace with NWConnection (iOS 12+)
       → See Migration 1 below

迁移 1：从 BSD 套接字迁移到 NWConnection

迁移映射

BSD Sockets	NWConnection	说明
socket() + connect()	NWConnection(host:port:using:) + start()	默认非阻塞
send() / sendto()	connection.send(content:completion:)	异步，立即返回
recv() / recvfrom()	connection.receive(minimumIncompleteLength:maximumLength:completion:)	异步，立即返回
bind() + listen()	NWListener(using:on:)	自动绑定端口
accept()	listener.newConnectionHandler	为每个连接调用回调
getaddrinfo()	让 NWConnection 处理 DNS	通过竞速进行智能解析
SCNetworkReachability	connection.stateUpdateHandler 等待状态	不存在竞态条件
setsockopt()	NWParameters 配置	类型安全的选项

迁移示例

迁移前（BSD Sockets）

// BEFORE — Blocking, manual DNS, error-prone
var hints = addrinfo()
hints.ai_family = AF_INET
hints.ai_socktype = SOCK_STREAM

var results: UnsafeMutablePointer<addrinfo>?
getaddrinfo("example.com", "443", &hints, &results)

let sock = socket(results.pointee.ai_family, results.pointee.ai_socktype, 0)
connect(sock, results.pointee.ai_addr, results.pointee.ai_addrlen) // BLOCKS

let data = "Hello".data(using: .utf8)!
data.withUnsafeBytes { ptr in
    send(sock, ptr.baseAddress, data.count, 0)
}

迁移后（NWConnection）

// AFTER — Non-blocking, automatic DNS, type-safe
let connection = NWConnection(
    host: NWEndpoint.Host("example.com"),
    port: NWEndpoint.Port(integerLiteral: 443),
    using: .tls
)

connection.stateUpdateHandler = { state in
    if case .ready = state {
        let data = Data("Hello".utf8)
        connection.send(content: data, completion: .contentProcessed { error in
            if let error = error {
                print("Send failed: \(error)")
            }
        })
    }
}

connection.start(queue: .main)

优势

• 20 行 → 10 行
• 无需手动处理 DNS、阻塞或不安全指针
• 自动支持 Happy Eyeballs、代理和 WiFi Assist

---

迁移 2：从 NWConnection 迁移到 NetworkConnection（iOS 26+）

迁移原因

• async/await 可消除回调地狱
• 内置 TLV 分帧和 Coder 协议
• 无需使用 [weak self]（async/await 会处理取消）
• 通过异步序列监控状态

迁移映射

NWConnection（iOS 12-25）	NetworkConnection（iOS 26+）	说明
connection.stateUpdateHandler = { state in }	for await state in connection.states { }	异步序列
connection.send(content:completion:)	try await connection.send(content)	挂起函数
connection.receive(minimumIncompleteLength:maximumLength:completion:)	try await connection.receive(exactly:)	挂起函数
手动进行 JSON 编码/解码	Coder(MyType.self, using: .json)	内置 Codable 支持
自定义分帧器	TLV { TLS() }	内置类型-长度-值
到处使用 [weak self]	无需使用 [weak self]	自动取消任务

迁移示例

迁移前（NWConnection）

// BEFORE — Completion handlers, manual memory management
let connection = NWConnection(host: "example.com", port: 443, using: .tls)

connection.stateUpdateHandler = { [weak self] state in
    switch state {
    case .ready:
        self?.sendData()
    case .waiting(let error):
        print("Waiting: \(error)")
    case .failed(let error):
        print("Failed: \(error)")
    default:
        break
    }
}

connection.start(queue: .main)

func sendData() {
    let data = Data("Hello".utf8)
    connection.send(content: data, completion: .contentProcessed { [weak self] error in
        if let error = error {
            print("Send error: \(error)")
            return
        }
        self?.receiveData()
    })
}

func receiveData() {
    connection.receive(minimumIncompleteLength: 10, maximumLength: 10) { [weak self] (data, context, isComplete, error) in
        if let error = error {
            print("Receive error: \(error)")
            return
        }
        if let data = data {
            print("Received: \(data)")
        }
    }
}

迁移后（NetworkConnection）

// AFTER — Async/await, automatic memory management
let connection = NetworkConnection(
    to: .hostPort(host: "example.com", port: 443)
) {
    TLS()
}

// Monitor states in background task
Task {
    for await state in connection.states {
        switch state {
        case .preparing:
            print("Connecting...")
        case .ready:
            print("Ready")
        case .waiting(let error):
            print("Waiting: \(error)")
        case .failed(let error):
            print("Failed: \(error)")
        default:
            break
        }
    }
}

// Send and receive with async/await
func sendAndReceive() async throws {
    let data = Data("Hello".utf8)
    try await connection.send(data)

    let received = try await connection.receive(exactly: 10).content
    print("Received: \(received)")
}

优势

• 30 行 → 15 行
• 无需嵌套回调，也无需使用 [weak self]
• 错误通过 throws 自然传播
• Task 退出时自动取消

---

迁移 3：从 URLSession StreamTask 迁移到 NetworkConnection

适合迁移的情况

• 需要使用 UDP（StreamTask 仅支持 TCP）
• 需要使用 TCP/TLS 之外的自定义协议
• 需要底层控制（数据包节奏、ECN、服务类别）

适合继续使用 URLSession 的情况

• 处理 HTTP/HTTPS（URLSession 针对此场景进行了优化）
• 需要 WebSocket 支持
• 需要内置缓存和 Cookie 处理

迁移示例

迁移前（URLSession StreamTask）

// BEFORE — URLSession for TCP/TLS stream
let task = URLSession.shared.streamTask(withHostName: "example.com", port: 443)

task.resume()

task.write(Data("Hello".utf8), timeout: 10) { error in
    if let error = error {
        print("Write error: \(error)")
    }
}

task.readData(ofMinLength: 10, maxLength: 10, timeout: 10) { data, atEOF, error in
    if let error = error {
        print("Read error: \(error)")
        return
    }
    if let data = data {
        print("Received: \(data)")
    }
}

迁移后（NetworkConnection）

// AFTER — NetworkConnection for TCP/TLS
let connection = NetworkConnection(
    to: .hostPort(host: "example.com", port: 443)
) {
    TLS()
}

func sendAndReceive() async throws {
    try await connection.send(Data("Hello".utf8))
    let data = try await connection.receive(exactly: 10).content
    print("Received: \(data)")
}

资源

技能：axiom-ios-networking、axiom-networking-legacy