CODEWITHSUNDEEP
javaperformancechrome-native-messaging
Aegis
Aegis

Reputation: 131

Optimize Native Message Host in Java for larger Strings

I am using Chrome's Native Messaging API to pass data to my host in Java. The data is a 512 KB long String encoded in Base64. The problem is that the Host is taking too long to read the data from the standard input. I read the following post: Very Slow to pass "large" amount of data from Chrome Extension to Host (written in C#) and I understand that the problem is how I read the bytes but I was’nt able to adapt that code to java so far.

The code of my host is:

try {

    // hilo principal de la aplicacion
    while(true){

        int length = 0;
        String input = "";
        String output = "";
        String outputType = "";

        // cargamos la logitud de caracteres en bytes
        byte[] bytes = new byte[4];
        System.in.read(bytes, 0, 4);
        length = getInt(bytes);

        // cargamos los datos enviados
        byte[] data = new byte[length];
        System.in.read(data, 0, length);

        if (length == 0){
            // si no recibimos datos ponemos un sleep para no comer todos los recursos del equipo
            Thread.sleep(50);
            break;
        }else{
            // Loop getchar to pull in the message until we reach the total length provided.
            for (int i=0; i < length; i++){

                input += (char) data[i];
            }

            // leemos el texto enviado del dato en JSON
            JSONObject obj = new JSONObject(input);
            String texto = obj.getString("text");

            System.err.write(("TEXT: " + texto).getBytes());

            // creamos el mensaje de respuesta y lo enviamos
            String respuesta = "{\"type\":\"TEST\", \"text\":\"" + texto + "\"}";

            System.out.write(getBytes(respuesta.length()));
            System.out.write(respuesta.getBytes(Charset.forName("UTF-8")));
        }

    }

} catch (Exception e) {
    e.printStackTrace();
}

I need help to adapt the code of my host in java to read the message quickly.

Upvotes: 0

Views: 378

Answers (1)

user207421
user207421

Reputation: 310957

  • You can do most of that, and without the bugs, with DataInputStream.readInt() and .readFully(). If you're on an Intel you will need to rearrange the int for native byte order, as this reads network byte order.
  • Put a BufferedInputStream between that and System.in: that will solve the major performance problem.
  • Solve the other performance problem via new String(data,...) instead of the appending loop.
  • It's hard to see why they would send you a zero length, but if they do, sleeping isn't going to accomplish anything except wasting time. Remove that.

Upvotes: 1

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