Added basic WebSocket functionality (no decoding yet)

code/src/Fitbot/app/src/main/java/com/example/fitbot/processing/MotionProcessor.java

@@ -1,4 +0,0 @@
-package com.example.fitbot.processing;
-
-public class MotionProcessor {
-}

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java

@@ -1,4 +1,4 @@
-package com.example.fitbot.processing;
+package com.example.fitbot.util.processing;
 
 public class MotionData {
 

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java

@@ -1,4 +1,6 @@
-package com.example.fitbot.processing;
+package com.example.fitbot.util.processing;
+
+import com.example.fitbot.util.server.WebSocket;
 
 import java.io.InputStream;
 
@@ -17,9 +19,14 @@ public class MotionInputStream extends InputStream {
      */
     public static MotionInputStream startListening()
     {
-        // Create server
-
+        // Create socket server
+        WebSocket socket = WebSocket.createServer(80);
 
+        // Check if the socket
+        if ( socket != null )
+        {
+            socket.startListening();
+        }
         return null;
     }
 

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java

@@ -0,0 +1,4 @@
+package com.example.fitbot.util.processing;
+
+public class MotionProcessor {
+}

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java

@@ -0,0 +1,15 @@
+package com.example.fitbot.util.server;
+
+import java.net.Socket;
+
+/**
+ * Interface for handling WebSocket events.
+ */
+public interface IWebSocketHandler {
+
+    // Function for handling the connection of the WebSocket.
+    default void onConnected(Socket socket) {}
+    default void onDisconnected(Socket socket) {}
+    default void onMessageReceived(String message) {}
+    default void onError(Socket socket, String error) {}
+}

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java

@@ -0,0 +1,66 @@
+package com.example.fitbot.util.server;
+
+import android.support.annotation.Nullable;
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public class WebSocket {
+
+    private ServerSocket serverSocket;
+    private WebSocketConnectionHandler connectionHandler;
+    private final Set<Socket> clients = Collections.synchronizedSet(new HashSet<>());
+    protected IWebSocketHandler eventHandler = new IWebSocketHandler() {}; // NO-OP event handler.
+
+    /**
+     * Constructor for creating a new WebSocket server.
+     */
+    private WebSocket() {}
+
+    /**
+     * Function for creating a new WebSocket server given the provided port.
+     * @param port The port to configure the server to.
+     * @return A WebSocket connection, or null if something went wrong.
+     */
+    public static @Nullable WebSocket createServer(int port) {
+        try {
+            WebSocket socket = new WebSocket();
+            socket.serverSocket = new ServerSocket(port);
+            return socket;
+        } catch (IOException error)
+        {
+            String cause = error.getMessage() == null ? "Unknown reason" : error.getMessage();
+            Log.e("WebSocket -- Creating new WebSocket server", cause);
+            return null;
+        }
+    }
+
+    /**
+     * Method for listening for incoming connections.
+     */
+    public void startListening() {
+        this.connectionHandler = new WebSocketConnectionHandler(this);
+        this.connectionHandler.listen();
+    }
+
+    /**
+     * Method for getting the ServerSocket connection
+     * @return The ServerSocket connection.
+     */
+    public ServerSocket getSocket() {
+        return this.serverSocket;
+    }
+
+    /**
+     * Method for checking whether this WebSocket connection is connected.
+     * @return The connection status of the WebSocket.
+     */
+    public boolean isConnected() {
+        return !this.serverSocket.isClosed();
+    }
+}

code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java

@@ -0,0 +1,88 @@
+package com.example.fitbot.util.server;
+
+import android.os.Build;
+import android.support.annotation.RequiresApi;
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Base64;
+import java.util.Scanner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class WebSocketConnectionHandler implements Runnable {
+
+    private final WebSocket theSocket;
+    private Thread thread;
+
+    /**
+     * Constructor for WebSocketConnectionHandler.
+     * This class handles all new incoming Socket connections.
+     * @param webSocket The socket to check for new connections.
+     */
+    protected WebSocketConnectionHandler(WebSocket webSocket) {
+        this.theSocket = webSocket;
+    }
+
+    @RequiresApi(api = Build.VERSION_CODES.O)
+    @Override
+    public void run() {
+        while (theSocket.isConnected()) {
+            try {
+                Socket newSocket = this.theSocket.getSocket().accept();
+                this.theSocket.eventHandler.onConnected(newSocket);
+
+                Scanner scanner = new Scanner(newSocket.getInputStream(), "UTF-8");
+                String data = scanner.useDelimiter("\\r\\n\\r\\n").next();
+                Matcher header = Pattern.compile("^GET").matcher(data);
+
+                // Check if the header contains the GET keyword
+                // If this is the case, upgrade the HTTP connection to WebSocket.
+                if (header.find()) {
+                    Matcher match = Pattern.compile("Sec-WebSocket-Key: (.*)").matcher(data);
+                    match.find();
+
+                    String SECAccept = Base64.getEncoder().encodeToString(
+                            MessageDigest.getInstance("SHA-1").digest((match.group(1) + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes(StandardCharsets.UTF_8)));
+
+                    byte[] response = (
+                            "HTTP/1.1 101 Switching Protocols\r\n" +
+                            "Connection: Upgrade\r\n" +
+                            "Upgrade: websocket\r\n" +
+                            "Sec-WebSocket-Accept: " +
+                            SECAccept + "\r\n\r\n").getBytes(StandardCharsets.UTF_8);
+                    newSocket.getOutputStream().write(response, 0, response.length);
+
+                    // TODO: Read data from socket and provide in onMessageReceived.
+
+                }
+
+            } catch (IOException | NoSuchAlgorithmException error) {
+                String reason = error.getMessage() == null ? "Unknown reason" : error.getMessage();
+                Log.e("WebSocketConnectionHandler", "Error listening to Socket connections: " + reason);
+                break;
+            }
+        }
+    }
+
+    /**
+     * Method for checking whether the connection handler is actively listening.
+     * @return Whether or not it's listening.
+     */
+    public boolean isActive() {
+        return this.thread.isAlive();
+    }
+
+    /**
+     * Method for listening to all new incoming socket connections.
+     */
+    public void listen() {
+        this.thread = new Thread(this);
+        this.thread.start();
+        Log.i("WebSocketConnectionHandler", "Listening started.");
+    }
+}