OSCTCPServer: init: port parameter now allows nil or 0 to assign a random available port

Author: orchetect

Sources/OSCKit/TCP/Server/OSCTCPServer.swift

@@ -37,7 +37,10 @@ public final class OSCTCPServer {
     public var timeTagMode: OSCTimeTagMode
 
     /// Local network port.
-    public private(set) var localPort: UInt16
+    public var localPort: UInt16 {
+        tcpSocket.localPort
+    }
+    private var _localPort: UInt16?
 
     /// Network interface to restrict connections to.
     public let interface: String?
@@ -51,21 +54,22 @@ public final class OSCTCPServer {
     ///
     /// - Parameters:
     ///   - port: Local network port to listen for inbound connections.
+    ///     If `nil` or `0`, a random available port in the system will be chosen.
     ///   - interface: Optionally specify a network interface for which to constrain connections.
     ///   - timeTagMode: OSC TimeTag mode. Default is recommended.
     ///   - framingMode: TCP framing mode. Both server and client must use the same framing mode. (Default is recommended.)
     ///   - queue: Optionally supply a custom dispatch queue for receiving OSC packets and dispatching the
     ///     handler callback closure. If `nil`, a dedicated internal background queue will be used.
     ///   - receiveHandler: Handler to call when OSC bundles or messages are received.
     public init(
-        port: UInt16,
+        port: UInt16?,
         interface: String? = nil,
         timeTagMode: OSCTimeTagMode = .ignore,
         framingMode: OSCTCPFramingMode = .osc1_1,
         queue: DispatchQueue? = nil,
         receiveHandler: OSCHandlerBlock? = nil
     ) {
-        self.localPort = port
+        _localPort = (port == nil || port == 0) ? nil : port
         self.interface = interface
         self.timeTagMode = timeTagMode
         self.framingMode = framingMode
@@ -90,10 +94,10 @@ extension OSCTCPServer: @unchecked Sendable { } // TODO: unchecked
 extension OSCTCPServer {
     /// Starts listening for inbound connections.
     public func start() throws {
-        try tcpSocket.accept(onInterface: interface, port: localPort)
-        
-        // update local port in case port 0 was passed and the system assigned a new port
-        localPort = tcpSocket.localPort
+        try tcpSocket.accept(
+            onInterface: interface,
+            port: _localPort ?? 0 // 0 causes system to assign random open port
+        )
     }
 
     /// Closes any open client connections and stops listening for inbound connection requests.

Tests/OSCKitTests/UDP/Server/OSCUDPServer Tests.swift

@@ -102,12 +102,12 @@ struct OSCUDPServer_Tests {
             }
         }
 
-        let possibleValuePacks: [OSCValues] = [
+        var possibleValuePacks: [OSCValues] { [
             [],
             [UUID().uuidString],
             [Int.random(in: 10_000 ... 10_000_000)],
             [Int.random(in: 10_000 ... 10_000_000), UUID().uuidString, 456.78, true]
-        ]
+        ] }
 
         let sourceMessages: [OSCMessage] = Array(1 ... 1000).map { value in
             OSCMessage("/some/address/\(UUID().uuidString)", values: possibleValuePacks.randomElement()!)
@@ -120,7 +120,7 @@ struct OSCUDPServer_Tests {
             }
         }
 
-        try await wait(require: { await receiver.messages.count == 1000 }, timeout: 5.0)
+        try await wait(require: { await receiver.messages.count == 1000 }, timeout: 10.0)
 
         await #expect(receiver.messages == sourceMessages)
     }
@@ -130,13 +130,15 @@ struct OSCUDPServer_Tests {
     func stressTestOnline() async throws {
         let isFlakey = !isSystemTimingStable()
 
-        let server = OSCUDPServer(port: 8888, timeTagMode: .ignore, queue: nil, receiveHandler: nil)
+        // selects a random available port
+        let server = OSCUDPServer(port: nil, timeTagMode: .ignore, queue: nil, receiveHandler: nil)
         try await Task.sleep(seconds: isFlakey ? 5.0 : 0.1)
 
         try server.start()
         try await Task.sleep(seconds: isFlakey ? 5.0 : 0.5)
 
-        print("Using server listen port \(server.localPort)")
+        let port = server.localPort
+        print("Using server listen port \(port)")
 
         final actor Receiver {
             var messages: [OSCMessage] = []
@@ -153,12 +155,12 @@ struct OSCUDPServer_Tests {
             }
         }
 
-        let possibleValuePacks: [OSCValues] = [
+        var possibleValuePacks: [OSCValues] { [
             [],
             [UUID().uuidString],
             [Int.random(in: 10_000 ... 10_000_000)],
             [Int.random(in: 10_000 ... 10_000_000), UUID().uuidString, 456.78, true]
-        ]
+        ] }
 
         let sourceMessages: [OSCMessage] = Array(1 ... 1000).map { value in
             OSCMessage("/some/address/\(UUID().uuidString)", values: possibleValuePacks.randomElement()!)
@@ -171,12 +173,12 @@ struct OSCUDPServer_Tests {
         let srcLocSendToServer: SourceLocation = #_sourceLocation
         DispatchQueue.global().async {
             for message in sourceMessages {
-                do { try client.send(message, to: "localhost", port: 8888) }
+                do { try client.send(message, to: "localhost", port: port) }
                 catch { Issue.record(error, sourceLocation: srcLocSendToServer) }
             }
         }
 
-        await wait(expect: { await receiver.messages.count == 1000 }, timeout: isFlakey ? 20.0 : 5.0)
+        await wait(expect: { await receiver.messages.count == 1000 }, timeout: isFlakey ? 20.0 : 10.0)
         try await #require(receiver.messages.count == 1000)
 
         await #expect(receiver.messages == sourceMessages)

Tests/OSCKitTests/UDP/Socket/OSCUDPSocket Tests.swift

@@ -140,9 +140,9 @@ struct OSCUDPSocket_Tests {
         let isFlakey = !isSystemTimingStable()
 
         let socket = OSCUDPSocket(
-            localPort: nil,
+            localPort: nil, // selects a random available port
             remoteHost: "localhost",
-            remotePort: nil,
+            remotePort: nil, // gets set to same port as localPort
             timeTagMode: .ignore,
             isIPv4BroadcastEnabled: false,
             queue: nil,