From ac7428607406922c78b7bdb2c85c46881382ccf6 Mon Sep 17 00:00:00 2001
From: Justin Mclean <justin@classsoftware.com>
Date: Wed, 19 Oct 2011 09:40:56 +1100
Subject: [PATCH] Added USB example. Currently not working correctly with
 serproxy.

---
 WebSocketsServerUSB.pde | 205 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)
 create mode 100644 WebSocketsServerUSB.pde

diff --git a/WebSocketsServerUSB.pde b/WebSocketsServerUSB.pde
new file mode 100644
index 0000000..4e2a5d8
--- /dev/null
+++ b/WebSocketsServerUSB.pde
@@ -0,0 +1,205 @@
+#include <sha1.h>
+#include <Base64.h>
+
+const char hex[] ="0123456789abcdef";
+
+boolean websocket = false;
+boolean handshakeDone = false;
+String key;
+
+void setup()
+{
+  pinMode(3,OUTPUT);
+  pinMode(5,OUTPUT);
+  pinMode(6,OUTPUT);
+  Serial.begin(57600);
+}
+
+// Read a line at a time
+String readLine()
+{
+  String data;
+  boolean lineEnd = false;
+
+  while (!lineEnd) 
+  {
+    if (Serial.available()) {
+      char c = Serial.read();
+      digitalWrite(6, HIGH);
+      delay(100);
+      digitalWrite(6  , LOW);
+      
+      if (c != '\n' && c != '\r') {
+        data.concat(c);
+      }
+      if (c == '\n') {
+        digitalWrite(3, HIGH);
+        delay(100);
+        digitalWrite(3, LOW);
+        lineEnd = true;
+      }
+    }
+  }
+  
+   return data;
+}
+
+// Return true is line is "blank"
+boolean blankLine(String line) {
+  return (line.length() == 0);
+}
+
+// Send a standard http response header
+void httpOK() {
+  Serial.println("HTTP/1.1 200 OK");
+  Serial.println("Content-Type: text/html");
+  Serial.println();
+}
+
+// Send a header to switch to the web sockets protocol
+void webSocketOK(String key) {
+  Serial.println("HTTP/1.1 101 Switching Protocols");
+  Serial.println("Upgrade: websocket");
+  Serial.println("Connection: Upgrade");
+  Serial.print("Sec-WebSocket-Accept: ");
+  Serial.println(key);
+  Serial.println();
+}
+
+// Convert a SHA1 hash to a string
+char* hashToString(uint8_t* hash) {
+  char hashStr[40];
+
+  for (int i=0; i < 20; i++) {
+    hashStr[2*i] = hex[hash[i] >> 4];
+    hashStr[2*i+1] = hex[hash[i] & 0xf];     
+  }
+  hashStr[40] = '\0';
+
+  return hashStr;
+}
+
+// read a HTTP header a line at a time and decode
+void readHeader() {
+  String line = readLine(); 
+  int colon = line.indexOf(":");
+
+  if (colon) {
+    String name = line.substring(0, colon).trim();
+    String value = line.substring(colon + 1).trim();
+    
+    if (name == "Upgrade" && value == "websocket") {
+      websocket = true;
+    }
+    if (name == "Sec-WebSocket-Key") {
+      key = value;
+    }
+  }
+
+  if (blankLine(line)) { 
+    if (websocket) { 
+      key = key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+      Sha1.init();
+      Sha1.print(key);
+      char* hash = (char*)Sha1.result();
+      char encode[29];
+      base64_encode(encode, hash, 20);
+      webSocketOK(encode);
+      handshakeDone = true;
+      digitalWrite(5, HIGH);
+      delay(100);
+      digitalWrite(5, LOW);
+    }
+    else {
+      httpOK();
+    }
+  }
+}
+
+// read and decode a web socket message
+String readMessage()
+{
+  String data;
+  unsigned char opcode;
+  unsigned char length;
+  boolean useMask;
+  unsigned char mask[4];
+
+  opcode = Serial.read();
+  //TODO check opcode
+  length = Serial.read();
+  useMask = ((length & 0x80) == 0x80);
+  length = length & 0x7F;
+  if (useMask) {
+    mask[0] = Serial.read();
+    mask[1] = Serial.read();
+    mask[2] = Serial.read();
+    mask[3] = Serial.read();
+  }
+
+  int noRead = 0;  
+  while (noRead < length) 
+  {
+    unsigned char masked = Serial.read();
+
+    if (useMask) {
+      unsigned char unmasked = masked ^ mask[noRead % 4];
+      data.concat(unmasked);
+    }
+    else {
+      data.concat(masked);
+    }
+
+    noRead++;
+  }
+
+  return data;
+}
+
+// encode and send a web socket message
+void sendMessage(String message) {
+  unsigned char mask[4];
+  int length = message.length();
+  
+  mask[0] = random(256);
+  mask[1] = random(256);
+  mask[2] = random(256);
+  mask[3] = random(256);
+  
+  Serial.write(0x81); // text message
+  Serial.write(length | 0x80); // length and mask
+  Serial.write(mask[0]);
+  Serial.write(mask[1]);
+  Serial.write(mask[2]);
+  Serial.write(mask[3]);
+  
+  int noWrite = 0;
+  while (noWrite < length) {
+    unsigned char masked = message.charAt(noWrite) ^ mask[noWrite % 4];
+    Serial.write(masked);
+    noWrite++;
+  }
+}
+
+// Run a command when a message is received
+void runCommand(String command) {
+  // Change to do what you want here
+  sendMessage(command); // simple echo
+}
+
+void loop()
+{
+    while (Serial.available())
+    {
+      if (!handshakeDone) {
+        readHeader();
+      }
+      else {
+        String message = readMessage();
+        runCommand(message);
+      }
+    }
+
+    handshakeDone = false;
+}
+