StreamDelegate stops to receive events after a amount of readings in swift - ios

Question

I have an iOS chat application that receives messages over a socket connection.
When user open the app after a long time and there are more than 50 unread messages, the server send over socket a message telling the number of unread messages, at this point the application show an alert with a progress bar and then the server send each one message.
So, the application get each one message on the StreamDelegate method stream(_ stream: Stream, handle eventCode: Stream.Event) and update the progress bar until the end of messages.
The problem is, when I have a large amount of unread messages (about 300+) at some point the StreamDelegate stops to receive the events with the messages, and none error messages is displayed.
I call the connect method on a global queue:
DispatchQueue.global().async {
self.connect(host, port: port)
}
This is my socket connect code:
fileprivate func connect(_ host: String, port: Int) {
postStatus(.connecting)
self.host = NSString(string: host)
self.port = UInt32(port)
self.log("connect to \(host):\(port)")
var readStream : Unmanaged<CFReadStream>?
var writeStream : Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(nil, self.host, self.port, &readStream, &writeStream)
self.inOk = false
self.outOk = false
self.inputStream = readStream!.takeRetainedValue()
self.outputStream = writeStream!.takeRetainedValue()
self.inputStream.delegate = self
self.outputStream.delegate = self
let mainThread = Thread.isMainThread;
let loop = mainThread ? RunLoop.main : RunLoop.current
self.inputStream.schedule(in: loop, forMode: RunLoopMode.defaultRunLoopMode)
self.outputStream.schedule(in: loop, forMode: RunLoopMode.defaultRunLoopMode)
self.inputStream.open()
self.outputStream.open()
self.timer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(connectionTimeout), userInfo: nil, repeats: false)
if(!mainThread) {
loop.run()
}
}
In the StreamDelegate method stream(_ stream: Stream, handle eventCode: Stream.Event) I get the message event and process it on the method read(String)
case Stream.Event.hasBytesAvailable:
if let timer = timer {
timer.invalidate()
self.timer = nil
}
let json = ChatLibSwift.readMessage(self.inputStream)
do {
if StringUtils.isNotEmpty(json) {
try self.read(json)
}
} catch let ex as NSError {
LogUtils.log("ERROR: \(ex.description)")
}
break
case Stream.Event.hasSpaceAvailable:
break
The method that read each one message:
static func readMessage(_ inputStream: InputStream) -> String {
do {
var lenBytes = [UInt8](repeating: 0, count: 4)
inputStream.read(&lenBytes, maxLength: 4)
// header
let i32: Int = Int(UInt32.init(lenBytes[3]) | UInt32.init(lenBytes[2]) << 8 | UInt32.init(lenBytes[1]) << 16 | UInt32.init(lenBytes[0]) << 24 )
var msg = [UInt8](repeating: 0, count: (MemoryLayout<UInt8>.size * Int(i32)))
let bytesRead = inputStream.read(&msg, maxLength: Int(i32))
if bytesRead == -1 {
print("<< ChatLib ERROR -1")
return ""
}
let s = NSString(bytes: msg, length: bytesRead, encoding: String.Encoding.utf8.rawValue) as String?
if let s = s {
if bytesRead == Int(i32) {
return s
}
else {
print("Error: readMessage \(s)")
}
return s
}
return ""
} catch {
return ""
}
}
Anyone has idea how to solve it?

Answer 1

The main idea is to force schedule the reading of the stream after a successful read operation:
let _preallocatedBufferSize = 64 * 1024
var _preallocatedBuffer = [UInt8](repeating: 0, count: MemoryLayout<UInt8>.size * Int(_preallocatedBufferSize))
var message : ....
func readMessage(_ inputStream: InputStream) {
if !inputStream.hasBytesAvailable || message.isCompleted {
return
}
var theBuffer : UnsafeMutablePointer<UInt8>?
var theLength : Int = 0
// try to get buffer from the stream otherwise use the preallocated buffer
if !inputStream.getBuffer(&theBuffer, length:&theLength) || nil == theBuffer
{
memset(&_preallocatedBuffer, 0, _preallocatedBufferSize)
let theReadCount = inputStream.read(&_preallocatedBuffer, maxLength:_preallocatedBufferSize)
if theReadCount > 0 {
theBuffer = _preallocatedBuffer;
theLength = theReadCount;
} else {
theBuffer = nil;
theLength = 0;
}
}
if nil != theBuffer && theLength > 0 {
_message.appendData(theBuffer, length:theLength)
self.perform(#selector(readMessage), with:inputStream, afterDelay:0.0, inModes:[RunLoopMode.defaultRunLoopMode])
}
}