Martin Barker Martin Barker - 1 month ago 7
HTTP Question

readLine() loop not exiting until remote client closes connection

I'm having a problem with a Java SocketServer, i'm building a very basic Java handled Web Server.

So i'm creating a socket server, this is the code from the run method as i have made the server threaded.
The problem i'm having is that the server code seems to freeze as

while((line = reader.readLine()) != null)
until the remote client closes the connection. I'm using the chrome plugin ARC (Advanced REST Client) to do the testing with.

public void start() throws ServerException{
this.running = true;

try{
this.server = new ServerSocket(this.port);
}catch(IOException ex){
System.err.println("Failed to create Server Port is inuse!");
throw new ServerException("Unable to bind to port '" + this.port + "'", ex);
}

while(!isStopped()){
Socket client = null;
try{
client = this.server.accept();
}catch(IOException ex){
if(isStopped()) {
return;
}
throw new ServerException("Error accepting client connection", ex);
}
new Thread(
new ServerWorker(client, this)
).start();
}
}


This is the ServerWorker

public void run(){
try {
InputStream input = clientSocket.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
OutputStream output = clientSocket.getOutputStream();
long time = System.currentTimeMillis();
ArrayList<String> lines = new ArrayList<String>();
String line;

while((line = reader.readLine()) != null){
lines.add(line);
}
String[] msg = new String[lines.size()];
msg = lines.toArray(msg);

output.write("HTTP/1.1 200\r\n".getBytes());
output.write("\r\n".getBytes());

new HandleConnection(msg).begin(output);

reader.close();
output.close();
System.out.println("Request processed: " + time);
} catch (IOException e) {
}
}


and finally this is the handler:

public void begin(OutputStream output){
for(int i = 0; i < lines.length; i++){
System.out.println(lines[i]);
}
try{
output.write("{\"Response\":\"Ok\"}\r\n".getBytes());
}catch(IOException e){}
}

EJP EJP
Answer

The problem i'm having is that the server code seems to freeze as while((line = reader.readLine()) != null) until the remote client closes the connection.

That's not a problem: it is the correct, specified behaviour.

The problem is that you aren't implementing HTTP correctly. You need a good knowledge of RFC 2616 and its successors, particularly the parts about content length add transfer encoding. This code doesn't exhibit any knowledge of it whatsoever.

And why for example are you sending HTTP 200 before processing the request? How do you know the request processor won't want to return a different code?

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