I'm using NWListener newConnectionHandler handler to get newConnection like this:
listener.newConnectionHandler = { [weak self] newConnection in
guard let self = self else { return }
newConnection.stateUpdateHandler = { [weak self] newState in
guard let self = self else { return }
...
...
print("Connection endpoint: \(newConnection.endpoint)")
}
newConnection.start(queue: self.queue)
}
This is prints:
10.0.1.2:62610
I need to get just ip address, to save it for later, but I wasn't able to find any property inside NWEndpoint to get it. I can do something like this:
var ipAddressWithPort = newConnection.endpoint.debugDescription
if let portRange = ipAddressWithPort.range(of: ":") {
ipAddressWithPort.removeSubrange(portRange.lowerBound..<ipAddressWithPort.endIndex)
}
But I don't like it at all. What is proper way to get ip address?
Thank you.
NWEndpoint is an enumeration (with associated values) for the different kinds of endpoints. The remote host of an accepted TCP connection will be an endpoint defined by host and port, and you can use a switch statement to extract those values.
If you just want a string representation of the host part, without the port, it would be
switch(connection.endpoint) {
case .hostPort(let host, _):
let remoteHost = "\(host)"
print(remoteHost) // 10.0.1.2
default:
break
}
Related
Premise
I'm using Apple's Network framework to create a peer-to-peer app. What I'm currently trying to do is:
Device A establishes a connection with Device B and sends data.
Device B saves the NWConnection information of Device A.
Device B establishes a connection with Device A again using the saved MWConnection information and sends data.
I modelled off Apple's demo, which is essentially this source code here. Unlike Apple's demo, which establishes a single two-way connection and maintains that connection at all times, my app connects to multiple devices that can drop in and out of the connections at any time. This is why I want to be able to a) distinguish a specific device and b) initiate a new connection.
Problem
The problem I'm having is being able to reconstruct the NWConnection object using the information provided when a connection has been established. There are two ways of instantiating this object.
init(host: NWEndpoint.Host, port: NWEndpoint.Port, using: NWParameters)
init(to: NWEndpoint, using: NWParameters)
My attempts have been trying to gather the endpoint information like the host and the port while the connection with the desired device has been established and instantiate NWEndpoint to be used in NWConnection. But, I haven't been able to re-establish the connection thus far.
Following is the portion of the object that is used to initiate a connection. My full code is modified, but Apple's counterpart can be seen here.
class PeerConnection {
weak var delegate: PeerConnectionDelegate?
weak var statusDelegate: StatusDelegate?
var connection: NWConnection?
let initiatedConnection: Bool
init(endpoint: NWEndpoint, interface: NWInterface?, passcode: String, delegate: PeerConnectionDelegate) {
self.delegate = delegate
self.initiatedConnection = true
let connection = NWConnection(to: endpoint, using: NWParameters(passcode: passcode))
self.connection = connection
startConnection()
}
init(connection: NWConnection, delegate: PeerConnectionDelegate) {
self.delegate = delegate
self.connection = connection
self.initiatedConnection = false
startConnection()
}
// Handle starting the peer-to-peer connection for both inbound and outbound connections.
func startConnection() {
guard let connection = connection else {
return
}
connection.stateUpdateHandler = { newState in
switch newState {
case .ready:
print("\(connection) established")
// When the connection is ready, start receiving messages.
self.receiveNextMessage()
// Notify your delegate that the connection is ready.
if let delegate = self.statusDelegate {
delegate.showConnectionStatus(.connectionSuccess("Connection Success"))
}
case .failed(let error):
print("\(connection) failed with \(error)")
// Cancel the connection upon a failure.
connection.cancel()
// Notify your delegate that the connection failed.
if let delegate = self.statusDelegate {
delegate.showConnectionStatus(.connectionFail("Connection Fail"))
}
default:
break
}
}
// Start the connection establishment.
connection.start(queue: .main)
}
}
This is how I receive data when another device sends it.
func receiveNextMessage() {
guard let connection = connection else {
return
}
/// Has to call itself again within the closure because the maximum message is once.
connection.receiveMessage { (content, context, isComplete, error) in
// Extract your message type from the received context.
if let message = context?.protocolMetadata(definition: GameProtocol.definition) as? NWProtocolFramer.Message {
self.delegate?.receivedMessage(content: content, message: message, connection: connection)
}
if error == nil {
// Continue to receive more messages until you receive and error.
self.receiveNextMessage()
}
}
}
Finally, following is how I attempt to reconstruct MWConnection:
func receivedMessage(content: Data?, message: NWProtocolFramer.Message, connection: NWConnection) {
switch(connection.endpoint) {
case .hostPort(let host, let port):
/// first attempt
let endpoint = NWEndpoint.hostPort(host: host, port: port)
let newConnection = PeerConnection(endpoint: endpoint, interface: nil, passcode: passcode, delegate: self)
/// second attempt
let connection = NWConnection(host: host, port: port, using: NWParameters(passcode: passcode))
let newConnection = PeerConnection(connection: connection, delegate: self)
default:
break
}
}
NWConnection is instantiated inside initializer of PeerConnection.
I'm trying GRPC-Swift for Client-Server application.
I'm using GRPC-Swift for both Client and Server
Client is an iPhone application, which I tried with iPhone Simulator.
I followed this link for Client-side streaming RPC.
When I send message to Server from Client, I got the following error message in the console from Server,
error io.grpc.server_channel_call : unable to determine http version
From the Server in the
HTTPProtocolSwitcher.swift
inside the function func channelRead(context: ChannelHandlerContext, data: NIOAny), it is checking for HTTPProtocolVersion, and it is missing.
How to send the HTTPVersion from the Client code?
Update:
Client Code
import GRPC
import NIO
class HTTPClient {
private let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
private var channel: ClientConnection?
private var client: ChatGuide_ChatGuideClient?
private var clientCall: ClientStreamingCall<ChatGuide_TextMessage, ChatGuide_TextMessage>?
func connect(host: String, port: Int) throws {
let channel = ClientConnection.secure(group: self.group)
.connect(host: host, port: port)
self.channel = channel
self.client = ChatGuide_ChatGuideClient(channel: channel)
}
func disconnect() {
do {
self.clientCall?.sendEnd(promise: nil)
_ = try self.clientCall?.status.wait()
try self.group.syncShutdownGracefully()
} catch let error {
print("\(type(of: self)): Could not shutdown gracefully -", error.localizedDescription)
}
}
func initiateClient() {
let timeAmount = TimeAmount.minutes(1)
let timeLimit = TimeLimit.timeout(timeAmount)
let options = CallOptions(timeLimit: timeLimit)
let call = self.client?.chat(callOptions: options)
call?.response.whenSuccess { (message) in
print("\(type(of: self)): Message from server -", message.text)
}
call?.response.whenFailure { (error) in
print("\(type(of: self)): Response error -", error.localizedDescription)
}
self.clientCall = call
}
func send(text: String) {
if self.clientCall == nil {
self.initiateClient()
}
let message = ChatGuide_TextMessage.with {
$0.text = text
}
self.clientCall?.sendMessage(message, promise: nil)
}
}
Hey Vignesh,
I am currently learning gRPC-Swift myself, so I hope I will be of service and not muck things further.
However, it looks to me that you are not configuring the HTTP/1.x layer in order to transfer Protobuf packets, if you take a look at the HTTP1ToGRPCServerCodec.swift file Here
I think you will have a much clearer idea of how to adjust your code, I am sorry I can't provide more details, however not being too sure myself without further testing and reviewing the codebase.
Best regards and keep me posted if indeed i was helpful,
cheers
From the Server I have initiated insecure Server as,
let server = Server.insecure(group: self.group)
From the Client I have initiated secure ClientConnection as,
let channel = ClientConnection.secure(group: self.group)
And I got this clarification from here
So I made the ClientConnection also insecure as,
let channel = ClientConnection.insecure(group: self.group)
And after this it is working now.
I'm trying to build a TCP server with SwiftNIO. The server starts in the net, but the clients don't know the ip address. Therefore I want to start an UDP server as well and if the clients comes up, he sends a broadcast message to the net. The server will receive and answer, so that the client now knows the IP address.
Is it possible to build something like this with SwiftNIO?
Yes, that's possible also there's not much support in SwiftNIO to make this easy.
See below for a commented example which will send HELLO WORLD once a second to en0's broadcast address and port 37020.
import NIO
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
defer {
try! group.syncShutdownGracefully()
}
let matchingInterfaces = try System.enumerateInterfaces().filter {
// find an IPv4 interface named en0 that has a broadcast address.
$0.name == "en0" && $0.broadcastAddress != nil
}
guard let en0Interface = matchingInterfaces.first, let broadcastAddress = en0Interface.broadcastAddress else {
print("ERROR: No suitable interface found. en0 matches \(matchingInterfaces)")
exit(1)
}
// let's bind the server socket
let server = try! DatagramBootstrap(group: group)
// enable broadast
.channelOption(ChannelOptions.socket(SOL_SOCKET, SO_BROADCAST), value: 1)
.bind(to: en0Interface.address)
.wait()
print("bound to \(server.localAddress!)")
var buffer = server.allocator.buffer(capacity: 32)
buffer.writeString("HELLO WORLD!")
var destAddr = broadcastAddress
destAddr.port = 37020 // we're sending to port 37020
// now let's just send the buffer once a second.
group.next().scheduleRepeatedTask(initialDelay: .seconds(1),
delay: .seconds(1),
notifying: nil) { task in
server.writeAndFlush(AddressedEnvelope(remoteAddress: destAddr,data: buffer)).map {
print("message sent to \(destAddr)")
}.whenFailure { error in
print("ERROR: \(error)")
// and stop if there's an error.
task.cancel()
server.close(promise: nil)
}
}
try server.closeFuture.wait()
In case you want to bind to 0.0.0.0 and send to 255.255.255.255 you can use this
import NIO
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
defer {
try! group.syncShutdownGracefully()
}
// let's bind the server socket
let server = try! DatagramBootstrap(group: group)
// enable broadast
.channelOption(ChannelOptions.socket(SOL_SOCKET, SO_BROADCAST), value: 1)
.bind(to: .init(ipAddress: "0.0.0.0", port: 0))
.wait()
print("bound to \(server.localAddress!)")
var buffer = server.allocator.buffer(capacity: 32)
buffer.writeString("HELLO WORLD!")
// we're sending to port 37020
let destPort = 37020
let destAddress = try SocketAddress(ipAddress: "255.255.255.255", port: destPort)
// now let's just send the buffer once a second.
group.next().scheduleRepeatedTask(initialDelay: .seconds(1),
delay: .seconds(1),
notifying: nil) { task in
server.writeAndFlush(AddressedEnvelope(remoteAddress: destAddress, data: buffer)).map {
print("message sent to \(destAddress)")
}.whenFailure { error in
print("ERROR: \(error)")
// and stop if there's an error.
task.cancel()
server.close(promise: nil)
}
}
try server.closeFuture.wait()
Anyone knows how to download the Tello sdk for iOS. I have visited the link https://www.ryzerobotics.com/tello, but it is not useful
There isn't an official SDK to download for the Tello. You can find the instructions at this link which provides details of sending UDP packets over a network connection to the drone. You can use CocoaAsyncSocket found on GitHub to help you create the connection to the socket and then pass the commands as ASCII data to the Tello.
Here is some sample code to get you going (which I wrote earlier today on my own website):
var socket = GCDAsyncUdpSocket()
let sendHost = "192.168.10.1"
let sendPort: UInt16 = 8889
let statePort: UInt16 = 8890
First, create the socket, a String with the Tello IP, and a couple of constants holding the port numbers (8889 is used to send commands to, and also receives responses back such as "OK" if the command was successful. 8890 is used for receiving telemetry from the drone multiple times per second.
This will send the initial "command" command to the Tello:
// Set the delegate and dispatch queue
socket.setDelegate(self)
socket.setDelegateQueue(DispatchQueue.main)
// Send the "command" command to the socket.
do {
try socket.bind(toPort: sendPort)
try socket.enableBroadcast(true)
try socket.beginReceiving()
socket.send("command".data(using: String.Encoding.utf8)!,
toHost: sendHost,
port: sendPort,
withTimeout: 0,
tag: 0)
} catch {
print("Command command sent.")
}
You need to make sure that the class conforms to GCDAsyncUdpSocketDelegate.
Implement the delegate method which receives data from the Tello.
func udpSocket(_ sock: GCDAsyncUdpSocket, didReceive data: Data, fromAddress address: Data, withFilterContext filterContext: Any?) {
let dataString = String(data: data, encoding: String.Encoding.utf8)
if (sock.localPort() == sendPort) {
print(dataString)
}
if (sock.localPort() == statePort) {
var telloStateDictionary = [String:Double]()
let stateArray = dataString?.components(separatedBy: ";")
for itemState in stateArray! {
let keyValueArray = itemState.components(separatedBy: ":")
if (keyValueArray.count == 2) {
telloStateDictionary[keyValueArray[0]] = Double(keyValueArray[1])
}
}
print(telloStateDictionary)
}
}
Set up port 8890 for listening to the telemetry:
let receiveSocket = GCDAsyncUdpSocket(delegate: self, delegateQueue: DispatchQueue.main)
do {
try receiveSocket.bind(toPort: statePort)
} catch {
print("Bind Problem")
}
do {
try receiveSocket.beginReceiving()
} catch {
print("Receiving Problem")
}
Run the app. Assuming you have manually connected to the Tello (like you would if you were controlling it with the Tello app), you should begin getting information back from the Tello.
To send more commands to it, such as "takeoff" or "cw 360", you can do something such as:
func sendCommand(command: String) {
let message = command.data(using: String.Encoding.utf8)
socket.send(message!, toHost: sendHost, port: sendPort, withTimeout: 2, tag: 0)
}
Pass in the command as a string, and this will send it to the Tello.
In my app I use Moya and Alamofire (And also Moya/RxSwift and Moya-ObjectMapper) libraries for all network requests and responses.
I would like to handle the response of all types of requests in one handler, but also uniquely handle every request.
For example for any request I can get the response "Not valid Version", I would like to avoid to check in every response if this error arrived.
Is there an elegant way to handle this use case with Moya?
Apparently that is very simple, You just should create your own plugin. And add it to your Provider instance (You can add it in the init function)
For example:
struct NetworkErrorsPlugin: PluginType {
/// Called immediately before a request is sent over the network (or stubbed).
func willSendRequest(request: RequestType, target: TargetType) { }
/// Called after a response has been received, but before the MoyaProvider has invoked its completion handler.
func didReceiveResponse(result: Result<Moya.Response, Moya.Error>, target: TargetType) {
let responseJSON: AnyObject
if let response = result.value {
do {
responseJSON = try response.mapJSON()
if let response = Mapper<GeneralServerResponse>().map(responseJSON) {
switch response.status {
case .Failure(let cause):
if cause == "Not valid Version" {
print("Version Error")
}
default:
break
}
}
} catch {
print("Falure to prase json response")
}
} else {
print("Network Error = \(result.error)")
}
}
}
I suggest to use generic parametrized method.
class DefaultNetworkPerformer {
private var provider: RxMoyaProvider<GitHubApi> = RxMoyaProvider<GitHubApi>()
func performRequest<T:Mappable>(_ request: GitHubApi) -> Observable<T> {
return provider.request(request).mapObject(T.self)
}
}
DefaultNetworkPerformer will handle all requests from you Moya TargetType. In my case it was GitHubApi. Example usage of this implementation is:
var networkPerformer = DefaultNetworkPerformer()
let observable: Observable<User> = networkPerformer.performRequest(GitHubApi.user(username: "testUser"))
here you 'inform' network performer that response will contain User object.
observable.subscribe {
event in
switch event {
case .next(let user):
//if mapping will succeed here you'll get an Mapped Object. In my case it was User that conforms to Mappable protocol
break
case .error(let error):
//here you'll get MoyaError if something went wrong
break
case .completed:
break
}
}