Get contents of inputStream to a string

1

When I connect to a server (TCP) I want to store received message in a string. I tried with read() but it reads one character and returns ASCII values

job = CoroutineScope(IO).launch {
    socket = Socket("192.168.0.11", 4000);
    while(socket.isConnected){
        socket.outputStream.write("Hello from the client!".toByteArray());
        var text : String = socket.inputStream.read().toString()
        Log.d("debug ", " result $text")
        delay(2000)
     }
}

It would be helpful if I could at least know when the server stops sending characters, equaling with null didn’t work. I also tried using reader with readText method instead, but it doesn’t return and just keeps reading/blocking (at least I don’t know how it can return a string value, it only returns when closing the connection).

val text = socket.inputStream.reader().use { reader ->  
    reader.readText()
}

For now I just want to receive a string from the server and log it to the console. The server returns a message after I send a request.

2

This looks like a design question rather than a coding one.

The problem is: how do you know ‘when the server stops sending characters’, if it keeps the connection open?

You could wait until no characters have been sent for a fixed amount of time. But that would introduce unnecessary latency, and risk premature return when the network is slow.

Better to have some in-band signal: either a delimiter, such as a newline character or zero byte, or precede the message with a character count (which must itself have a fixed size).

Once you decide what sort of signalling to use, you can look at how to implement it.

3

Once I send a request the server returns a string, but there are no special characters and I don’t know how long the string will be, I didn’t design the server

4

If you don’t have controll over the server there should be some sort of documentation of the API you use that should explain how strings are ended. There is really no 1 standard way of doing this.
@gidds named the most common options but there is really no way to know this about a random API. The best you can do is look through the API documentation or ask the people who designed the server.

5

So there’s no way to know when the server sent last byte of a message. I guess it makes sense, but this is my first program that deals with asynchronous communication so there’s a lot to learn. I have short documentation, but the only thing that I see is, that the message always starts with either K or O.