Add node.js version of Rendezvous server.

Add node.js version of Rendezvous server. This version uses memcache
for storing rendezvous data. It logs information from phones to a
CouchDB Database.

Change-Id: I2b76750681e20b8aea56c507a7727c33ca3c2987

appinventor/misc/rendezvous/README.md

+node.js version of MIT App Inventor Rendezvous Server
+===
+
+This codebase provides the basic functions of the Rendezvous
+Server. It also logs to a CouchDB instance the POST's received from
+the phone. This database can then be mined for statistics.
+
+### To Run:
+
+Prerequisites:
+
+     * Node.js (tested with version v0.8.21)
+     * CouchDB -- for stats
+     * npm install memcache
+     * npm install nano
+
+Setup a user named "appinv" (should be a system account, but doesn't have to be).
+The "appinv" userid's home directory should be in /home/appinv
+
+  - Put rendezvous.js in /home/appinv.
+  - Put rendezvous.conf in /etc/init for upstart (Ubuntu 12.04LTS).
+  - Put the database URI in /home/appinv/uri.
\ No newline at end of file

appinventor/misc/rendezvous/rendezvous.conf

+description "Rendezvous node.js server"
+author  "jis"
+
+start on (local-filesystems and net-device-up IFACE=eth0)
+stop on shutdown
+
+respawn
+
+script
+   touch /home/appinv/rendezvous.log
+   chown appinv /home/appinv/rendezvous.log
+   su -s /bin/sh -c 'exec "$0" "$@"' appinv -- /usr/local/bin/node /home/appinv/rendezvous.js >> /home/appinv/rendezvous.log 2>&1
+end script

appinventor/misc/rendezvous/rendezvous.js

+var http = require('http');
+var requestHandler = http.IncomingMessage.prototype;
+var memcache = require('memcache');
+var mc = new memcache.Client();
+mc.connect();
+var querystring = require('querystring');
+var fs = require('fs')
+
+/*
+ *  Database Handler
+ *
+ */
+
+var db = { 'connection' : null,
+	   'insert' : function(key, ua, ip) {
+	       var entry;
+	       try {
+		   var data = { 'key' : key, 'ip' : ip, 'ua' : ua,
+				'ts' : (new Date()).toISOString()};
+		   this.queue.push(data);
+		   if (!this.connection) {
+		       console.log('Opening a new connection.');
+		       if (!this.uri) {
+			   console.log("Do not have URI yet, queuing.");
+		       } else {
+			   var nano = require('nano')(this.uri);
+			   this.connection = nano.use('companion');
+		       }
+		   }
+		   while (entry = this.queue.pop())
+		       this.connection.insert(data);
+	       } catch (err) {
+		   console.log(err);
+		   console.log(err.stack);
+		   this.connection = null; // Force reconnect next time
+	       }
+	   },
+	   'queue' : []
+	 }
+
+fs.readFile('/home/appinv/uri', function(err, data) {
+    if (err)
+	throw err;
+    db.uri = data.toString();
+});
+
+/**
+ * Add a uniform interface for remote address in Node.js
+ *
+ * From: https://gist.github.com/3rd-Eden/1740741
+ * @api private
+ */
+
+requestHandler.__defineGetter__('remote', function remote () {
+  var connection = this.connection
+    , headers = this.headers
+    , socket = connection.socket;
+
+  // return early if we are behind a reverse proxy
+  if (headers['x-forwarded-for']) {
+    return {
+        ip: headers['x-forwarded-for']
+      , port: headers['x-forwarded-port']
+    }
+  }
+
+  // regular HTTP servers
+  if (connection.remoteAddress) {
+    return {
+        ip: connection.remoteAddress
+      , port: connection.remotePort
+    };
+  }
+
+  // in node 0.4 the remote address for https servers was in a different
+  // location
+  if (socket.remoteAddress) {
+    return {
+        ip: socket.remoteAddress
+      , port: socket.remotePort
+    };
+  }
+
+  // last possible location..
+  return {
+      ip: this.socket.remoteAddress || '0.0.0.0'
+    , port: this.socket.remotePort || 0
+  }
+});
+
+var server = function(request, response) {
+    var data = "";
+    if (request.method == 'POST') { // A phone checking in
+	request.on('data', function(chunk) {
+	    data += chunk.toString();
+	});
+	request.on('end', function() {
+	    data = querystring.parse(data);
+	    var key = data['key'];
+	    if (key) {
+		var json = JSON.stringify(data);
+		mc.set('rr-' + key, json, 120); // Save for two minutes.
+	    }
+	    db.insert(key, request.headers['user-agent'], request.remote.ip);
+	    response.writeHead(200, "OK", { "Content-Type" : "text/plain",
+					    "Access-Control-Allow-Origin" : "*",
+					    "Access-Control-Allow-Headers" : "origin, content-type"});
+	    response.end("OK\n");
+	});
+    } else if (request.method == 'OPTIONS') {
+	response.writeHead(200, "OK", { "Content-Type" : "text/html",
+					"Access-Control-Allow-Origin" : "*",
+					"Access-Control-Allow-Headers" : "origin, content-type"});
+	response.end("");
+    } else {
+	var url = request.url.split('/');
+	var key = url[url.length-1];
+	if (key) {
+	    mc.get('rr-' + key, function(err, result) {
+		response.writeHead(200, "OK", { "Content-Type" : "application/json",
+						"Access-Control-Allow-Origin" : "*",
+						"Access-Control-Allow-Headers" : "origin, content-type"});
+//		console.log(request.remote);
+		response.end(result);
+	    });
+	} else {		// Not found
+	    response.writeHead(200, "OK", { "Content-Type" : "application/json",
+					    "Access-Control-Allow-Origin" : "*",
+					    "Access-Control-Allow-Headers" : "origin, content-type"});
+	    response.end("");
+	}
+    }
+}
+
+http.createServer(server).listen(3000);