如何在swift中显式读取NSInputStream中的数据？

Question

我在我的应用程序中使用套接字连接。

这是我的SocketConnection.swift

    init(host: String, port:UInt32){
        self.host = host
        self.port = port
        self.status = false
        output = ""
        super.init()
    }

    func stream(aStream: NSStream, handleEvent aStreamEvent: NSStreamEvent) {
        switch aStreamEvent {

        case NSStreamEvent.OpenCompleted:
            break

        case NSStreamEvent.HasBytesAvailable:

            break

        case NSStreamEvent.HasSpaceAvailable:
            break

        case NSStreamEvent.EndEncountered:

//            aStream.close()
            aStream.removeFromRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
            break

        case NSStreamEvent.None:

            break

        case NSStreamEvent.ErrorOccurred:

            break

        default:
            println("# something weird happend")
            break
        }
    }

    func connect() {
        println("# connecting to \(host):\(port)")
        var cfReadStream : Unmanaged<CFReadStream>?
        var cfWriteStream : Unmanaged<CFWriteStream>?

        CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host, port, &cfReadStream, &cfWriteStream)
        inputStream = cfReadStream!.takeRetainedValue()
        outputStream = cfWriteStream!.takeRetainedValue()

        inputStream!.delegate = self
        outputStream!.delegate = self

        inputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
        outputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

        inputStream!.open()
        outputStream!.open()
    }


    func read(){  
        var buffer = [UInt8](count: bufferSize, repeatedValue: 0)
        output = ""
        while (self.inputStream!.hasBytesAvailable){
            var bytesRead: Int = inputStream!.read(&buffer, maxLength: buffer.count)
            if bytesRead >= 0 {
                output += NSString(bytes: UnsafePointer(buffer), length: bytesRead, encoding: encoding)! as String
            } else {
                println("# error")
            }
            println("> \(output)")
        }
    }

    func send(message:String){        
            let data:NSData = message.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
            let bytesWritten = self.outputStream!.write(UnsafePointer(data.bytes), maxLength: data.length)
            println("< send to \(host)")

    }

在我的ViewController.swift中，我像这样连接到服务器

var socketConnection = SocketConnection(host: _ip, port: _port) 
socketConnection.connect() 
socketConnection.send(urlString) 
socketConnection.read()

现在我可以通过套接字发送url字符串，但是当我显式读取时，如果我从打印服务器响应的NSStreamEvent.HasBytesAvailable实例中调用相同的读取函数，则无法从服务器获取数据。但是如何触发事件队列呢？

我想显式地调用这个socketConnection.read() ..我该怎么做呢？

连接2秒后，它会关闭连接通道，我想让连接保持活动状态，直到关闭。

帮我解决这个问题。

谢谢

Answer 1

如下所示更改您的read()，然后在case NSStreamEvent.HasBytesAvailable中调用read()函数：

private func read(stream: InputStream) {
    let maxReadLength = 1024
    let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: maxReadLength)
    while stream.hasBytesAvailable {
        let numberOfBytesRead = inputStream?.read(buffer, maxLength: maxReadLength)

        if numberOfBytesRead! < 0 {
            if let _ = inputStream?.streamError {
                break
            }
        }

        if let message = processedMessageString(buffer: buffer, length: numberOfBytesRead!) {
            delegate?.receivedMessage(message: message)
        }
    }
}

Answer 2

您不需要显式调用读取功能。如下所示更改您的读取函数，并在case case中调用Stream.Event.hasBytesAvailable：。

func read(stream: InputStream) {
let maxReadLength = 1024
var buffer = [uint8](repeating: 0, count: maxReadLength)
while stream.hasBytesAvailable {
    let numberOfBytesRead : Int = stream.read(&buffer, maxLength: maxReadLength)
    if numberOfBytesRead < 0 {
        if let _ = stream.streamError {
            break
        }
    }

    if let message = processedMessageString(buffer: buffer, length: numberOfBytesRead) {
        delegate?.receivedMessage(message: message)
    }
}}

如果您想显式调用read()，则需要将流作为参数传递，并在ViewController类中调用read函数。

socketConnection.read(stream)