Network framework migration guides. Use when migrating from BSD sockets to NWConnection, NWConnection to NetworkConnection (iOS 26+), or URLSession StreamTask to NetworkConnection.
/plugin marketplace add CharlesWiltgen/Axiom/plugin install axiom@axiom-marketplaceThis skill inherits all available tools. When active, it can use any tool Claude has access to.
| BSD Sockets | NWConnection | Notes |
|---|---|---|
socket() + connect() | NWConnection(host:port:using:) + start() | Non-blocking by default |
send() / sendto() | connection.send(content:completion:) | Async, returns immediately |
recv() / recvfrom() | connection.receive(minimumIncompleteLength:maximumLength:completion:) | Async, returns immediately |
bind() + listen() | NWListener(using:on:) | Automatic port binding |
accept() | listener.newConnectionHandler | Callback for each connection |
getaddrinfo() | Let NWConnection handle DNS | Smart resolution with racing |
SCNetworkReachability | connection.stateUpdateHandler waiting state | No race conditions |
setsockopt() | NWParameters configuration | Type-safe options |
// 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)
}
// 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)
| NWConnection (iOS 12-25) | NetworkConnection (iOS 26+) | Notes |
|---|---|---|
connection.stateUpdateHandler = { state in } | for await state in connection.states { } | Async sequence |
connection.send(content:completion:) | try await connection.send(content) | Suspending function |
connection.receive(minimumIncompleteLength:maximumLength:completion:) | try await connection.receive(exactly:) | Suspending function |
| Manual JSON encode/decode | Coder(MyType.self, using: .json) | Built-in Codable support |
| Custom framer | TLV { TLS() } | Built-in Type-Length-Value |
[weak self] everywhere | No [weak self] needed | Task cancellation automatic |
// 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)")
}
}
}
// 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)")
}
// 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)")
}
}
// 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)")
}
Skills: axiom-ios-networking, axiom-networking-legacy
This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "when to use description", "agent examples", "agent tools", "agent colors", "autonomous agent", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
This skill should be used when the user asks to "create a slash command", "add a command", "write a custom command", "define command arguments", "use command frontmatter", "organize commands", "create command with file references", "interactive command", "use AskUserQuestion in command", or needs guidance on slash command structure, YAML frontmatter fields, dynamic arguments, bash execution in commands, user interaction patterns, or command development best practices for Claude Code.
This skill should be used when the user asks to "create a hook", "add a PreToolUse/PostToolUse/Stop hook", "validate tool use", "implement prompt-based hooks", "use ${CLAUDE_PLUGIN_ROOT}", "set up event-driven automation", "block dangerous commands", or mentions hook events (PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification). Provides comprehensive guidance for creating and implementing Claude Code plugin hooks with focus on advanced prompt-based hooks API.