iOS Data Stream example

[jasperaelvoet]

Hi, I am trying to create two data streams between two iOS devices. However, I have unable to get it to work, and there seems to be no clear example in the documentation.

Here is how I create the Stream objects (this runs when a connection has been successfully established):

var inputStream: InputStream?
var outputStream: OutputStream?

Stream
  .getBoundStreams(
    withBufferSize: 1024,
    inputStream: &inputStream,
    outputStream: &outputStream)

guard let inputStream = inputStream, let outputStream = outputStream
else
{
  print("Failed to create input/output streams")
  return
}

nearbyConnectionManager
  .startStream(
    inputStream,
    to: [endpointID])

self.connectedPeers[connectedIndex].audioStream = outputStream
self.connectedPeers[connectedIndex].audioStream!.schedule(in: .main, forMode: .default)
self.connectedPeers[connectedIndex].audioStream!.open()

And then the receiving of the streams:

public func connectionManager(
  _ connectionManager: ConnectionManager, didReceive stream: InputStream,
  withID payloadID: PayloadID, from endpointID: EndpointID,
  cancellationToken token: CancellationToken)
{
  print("Received stream from \(endpointID)")

  stream.open()
  stream.delegate = self
  stream.schedule(in: .current, forMode: .default)
}

For testing purposes, I send 10 bytes 4x per second.

On the receiving end, I get this error:

Received stream from ZCUF
TRANSFER UPDATE: progress(<NSProgress: 0x303c06400> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 10 of -1  )
E0000 00:00:1734809808.195350 3542100 payload_manager.cc:1424] ProcessDataPacket: [data: error] endpoint_id=ZCUF; payload_id=3260928757190108707
I0000 00:00:1734809808.195654 3542213 client_proxy.cc:1061] ClientProxy [reporting onPayloadProgress]: client=11369573624546782; endpoint_id=ZCUF; payload_id=3260928757190108707, payload_status=Failure
TRANSFER UPDATE: failure

I tried modifying feature flags to see if that would resolve the issue, but was unsuccessful.

Would be great if someone could share a working example!

Thanks in advance

[jasperaelvoet]

So, not sure what I changed but receiving a stream seems to be working now.

 public func connectionManager(
    _ connectionManager: ConnectionManager, didReceive stream: InputStream,
    withID payloadID: PayloadID, from endpointID: EndpointID,
    cancellationToken token: CancellationToken)
  {
    print("Received stream from \(endpointID)")

    self.stream = stream

    let delegate = MPStreamDelegates()
    streamDelegate = delegate

    stream.delegate = delegate

    if stream.delegate === delegate
    {
      print("Delegate assigned successfully.")
    }
    else
    {
      print("Delegate assignment failed.")
    }

    stream.schedule(in: .main, forMode: .default)
    stream.open()
}

class MPStreamDelegates: NSObject, StreamDelegate {
  public func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
    print("Stream event: \(eventCode)")

    switch eventCode {
    case .endEncountered:
      print("endEncountered")
    case .hasBytesAvailable:
      if let inputStream = aStream as? InputStream {
        let bufferSize = 512
        var buffer = [UInt8](repeating: 0, count: bufferSize)
        let bytesRead = inputStream.read(&buffer, maxLength: bufferSize)

        if bytesRead > 0 {
          print("read \(bytesRead)")
        } else {
          print("No new data available or end of stream.")
          break
        }
      }
    case .endEncountered:
      print("Stream ended")
      aStream.close()
      aStream.remove(from: .current, forMode: .default)
    case .errorOccurred:
      print("Stream error: \(aStream.streamError?.localizedDescription ?? "Unknown error")")
    case .openCompleted:
      print("Stream opened")
    case .hasSpaceAvailable:
      print("Stream has space available")
    default:
      print("Other stream event")
    }
  }
}

logs:

Received stream from UCIG
Delegate assigned successfully.
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 2 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 4 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 6 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 8 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 10 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 12 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 14 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 16 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 18 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 20 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 22 of -1  )
TRANSFER UPDATE: progress(<NSProgress: 0x300436f80> : Parent: 0x0 (portion: 0) / Fraction completed: 0.0000 / Completed: 24 of -1  )

However, I have been unsuccessful actually reading the stream. Not sure what's going on here, on the Multipeer Connectivity framework this stream delegate worked fine.

[jasperaelvoet]

So, I was able to fix it. Instead of scheduling the stream when receiving it just open it. and then when receiving a progress update of the stream, manually read it.

[jasperaelvoet]

So, turns it isn't fixed, it is now just reading all the data in the beginning of the stream each time. Instead of actually advancing, through the stream. I also see the memory usage continuously increasing over time.

[jasperaelvoet]

Okay, so I fixed the repeating data part, but there is still the issue where the memory continues to increase. This is probably related to #2147