Initial import

Pusher.java

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+
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.math.BigInteger;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.security.InvalidKeyException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.mortbay.log.Log;
+
+import com.google.appengine.api.urlfetch.HTTPHeader;
+import com.google.appengine.api.urlfetch.HTTPMethod;
+import com.google.appengine.api.urlfetch.HTTPRequest;
+import com.google.appengine.api.urlfetch.HTTPResponse;
+import com.google.appengine.api.urlfetch.URLFetchService;
+import com.google.appengine.api.urlfetch.URLFetchServiceFactory;
+
+/**
+ * Static class to send messages to Pusher's REST API.
+ * 
+ * Please set pusherApplicationId, pusherApplicationKey, pusherApplicationSecret accordingly
+ * before sending any request. 
+ * 
+ * @author Stephan Scheuermann
+ * Copyright 2010. Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
+ */
+public class Pusher {
+
+	/**
+	 *  Pusher Host name
+	 */
+	private final static String pusherHost = "api.pusherapp.com";
+	
+	/**
+	 * Pusher Application Identifier
+	 */
+	private final static String pusherApplicationId = "";
+	
+	/**
+	 * Pusher Application Key
+	 */
+	private final static String pusherApplicationKey = "";
+	
+	/**
+	 * Pusher Secret
+	 */
+	private final static String pusherApplicationSecret = "";
+	
+	/**
+	 * Converts a byte array to a string representation
+	 * @param data
+	 * @return
+	 */
+	private static String byteArrayToString(byte[] data){
+    	BigInteger bigInteger = new BigInteger(1,data);
+    	String hash = bigInteger.toString(16);
+    	// Zero pad it
+    	while(hash.length() < 32 ){
+    	  hash = "0" + hash;
+    	}
+    	return hash;
+	}
+	
+	/**
+	 * Returns a md5 representation of the given string
+	 * @param data
+	 * @return
+	 */
+	private static String md5Representation(String data) {
+        try {
+        	//Get MD5 MessageDigest
+        	MessageDigest messageDigest = MessageDigest.getInstance("MD5");
+        	byte[] digest = messageDigest.digest(data.getBytes("US-ASCII"));
+        	return byteArrayToString(digest);
+        } catch (NoSuchAlgorithmException nsae) {
+            //We should never come here, because GAE has a MD5 algorithm
+        	throw new RuntimeException("No MD5 algorithm");
+        } catch (UnsupportedEncodingException e) {
+            //We should never come here, because UTF-8 should be available
+        	throw new RuntimeException("No UTF-8");
+		}	
+	}
+	
+	/**
+	 * Returns a HMAC/SHA256 representation of the given string
+	 * @param data
+	 * @return
+	 */
+    private static String hmacsha256Representation(String data) {
+        try {
+            // Create the HMAC/SHA256 key from application secret
+            final SecretKeySpec signingKey = new SecretKeySpec( pusherApplicationSecret.getBytes(), "HmacSHA256");
+
+            // Create the message authentication code (MAC)
+            final Mac mac = Mac.getInstance("HmacSHA256");
+            mac.init(signingKey);
+            
+            //Process and return data
+            byte[] digest = mac.doFinal(data.getBytes("UTF-8"));
+            digest = mac.doFinal(data.getBytes());
+            return byteArrayToString(digest);            
+        } catch (NoSuchAlgorithmException nsae) {
+            //We should never come here, because GAE has HMac SHA256
+        	throw new RuntimeException("No HMac SHA256 algorithm");
+        } catch (UnsupportedEncodingException e) {
+            //We should never come here, because UTF-8 should be available
+        	throw new RuntimeException("No UTF-8");
+		} catch (InvalidKeyException e) {
+			throw new RuntimeException("Invalid key exception while converting to HMac SHA256");
+		} 
+    }	
+
+    /**
+     * Build query string that will be appended to the URI and HMAC/SHA256 encoded
+     * @param eventName
+     * @param jsonData
+     * @return
+     */
+    private static String buildQuery(String eventName, String jsonData, String socketID){
+    	StringBuffer buffer = new StringBuffer();
+    	//Auth_Key
+    	buffer.append("auth_key=");
+    	buffer.append(pusherApplicationKey);
+    	//Timestamp
+    	buffer.append("&auth_timestamp=");
+    	buffer.append(System.currentTimeMillis() / 1000);
+    	//Auth_version
+    	buffer.append("&auth_version=1.0");
+    	//MD5 body
+    	buffer.append("&body_md5=");
+    	buffer.append(md5Representation(jsonData));
+    	//Event Name
+    	buffer.append("&name=");
+    	buffer.append(eventName);
+		//Append socket id if set
+		if (!socketID.isEmpty()) {
+			buffer.append("&socket_id=");
+			buffer.append(socketID);
+		}
+		//Return content of buffer
+		return buffer.toString();
+    }
+    
+    /**
+     * Build path of the URI that is also required for Authentication
+     * @return
+     */
+    private static String buildURIPath(String channelName){
+    	StringBuffer buffer = new StringBuffer();
+    	//Application ID
+    	buffer.append("/apps/");
+    	buffer.append(pusherApplicationId);
+    	//Channel name
+    	buffer.append("/channels/");
+    	buffer.append(channelName);
+    	//Event
+    	buffer.append("/events");    	
+		//Return content of buffer
+		return buffer.toString();    	
+    }
+    
+    /**
+     * Build authentication signature to assure that our event is recognized by Pusher
+     * @param uriPath
+     * @param query
+     * @return
+     */
+    private static String buildAuthenticationSignature(String uriPath, String query){
+    	StringBuffer buffer = new StringBuffer();
+    	//request method
+    	buffer.append("POST\n");
+    	//URI Path
+    	buffer.append(uriPath);
+    	buffer.append("\n");
+    	//Query string
+    	buffer.append(query);
+    	//Encode data
+    	String h = buffer.toString();
+    	return hmacsha256Representation(h);    	
+    }
+    
+    /**
+     * Build URI where request is send to
+     * @param uriPath
+     * @param query
+     * @param signature
+     * @return
+     */
+    private static URL buildURI(String uriPath, String query, String signature){
+    	StringBuffer buffer = new StringBuffer();
+    	//Protocol
+    	buffer.append("http://");
+    	//Host
+    	buffer.append(pusherHost);
+    	//URI Path
+    	buffer.append(uriPath);
+    	//Query string
+    	buffer.append("?");
+    	buffer.append(query);
+    	//Authentication signature
+    	buffer.append("&auth_signature=");
+    	buffer.append(signature);
+    	//Build URI
+    	try {
+			return new URL(buffer.toString());
+		} catch (MalformedURLException e) {
+			throw new RuntimeException("Malformed URI");
+		}
+    }
+    
+    /**
+     * Delivers a message to the Pusher API without providing a socket_id
+     * @param channel
+     * @param event
+     * @param jsonData
+     * @return
+     */
+    public static HTTPResponse triggerPush(String channel, String event, String jsonData){
+    	return triggerPush(channel, event, jsonData, "");
+    }
+    
+    /**
+     * Delivers a message to the Pusher API
+     * @param channel
+     * @param event
+     * @param jsonData
+     * @param socketId
+     * @return
+     */
+    public static HTTPResponse triggerPush(String channel, String event, String jsonData, String socketId){
+    	//Build URI path
+    	String uriPath = buildURIPath(channel);
+    	//Build query
+    	String query = buildQuery(event, jsonData, socketId);
+    	//Generate signature
+    	String signature = buildAuthenticationSignature(uriPath, query);
+    	//Build URI
+    	URL url = buildURI(uriPath, query, signature);
+    	
+    	//Create Google APP Engine Fetch URL service and request
+		URLFetchService urlFetchService = URLFetchServiceFactory.getURLFetchService();
+		HTTPRequest request = new HTTPRequest(url, HTTPMethod.POST);
+		request.addHeader(new HTTPHeader("Content-Type", "application/json"));
+		request.setPayload(jsonData.getBytes());
+		
+		//Start request
+		try {
+			return urlFetchService.fetch(request);
+		} catch (IOException e) {
+			//Log warning
+			Log.warn("Pusher request could not be send to the following URI " + url.toString());
+			return null;
+		}    	
+    }
+
+}

PusherRequest.java

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+
+
+import com.google.appengine.api.urlfetch.HTTPResponse;
+
+/**
+ * An instance of this class can be used to prepopulate properties (event or channel name) with default values
+ * 
+ * @author Stephan Scheuermann
+ * Copyright 2010. Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
+ */
+public class PusherRequest {
+
+	/**
+	 * Name of the event
+	 */
+	private String eventName;
+	
+	/**
+	 * Channel identifier
+	 */
+	private String channelName;	
+	
+	/**
+	 * Create an instance and assign a channelName that is used for each request
+	 * @param channelName
+	 */
+	public PusherRequest(String channelName) {
+		super();
+		this.channelName = channelName;
+	}
+	
+	/**
+	 * Create an instance and assign both channelName and eventName that are used for each request
+	 * @param eventName
+	 * @param channelName
+	 */
+	public PusherRequest(String channelName, String eventName) {
+		super();
+		this.channelName = channelName;
+		this.eventName = eventName;
+	}
+	
+	/**
+	 * Triggers a new push with default channelName, eventName properties
+	 * @param jsonData
+	 * @return
+	 */
+	public HTTPResponse triggerPush(String jsonData){
+		return Pusher.triggerPush(channelName, eventName, jsonData);
+	}	
+
+	/**
+	 * Triggers a new push with default channelName property
+	 * @param jsonData
+	 * @param eventName
+	 * @return
+	 */
+	public HTTPResponse triggerPush(String jsonData, String eventName){	
+		return Pusher.triggerPush(channelName, eventName, jsonData);
+	}
+	
+	/**
+	 * Triggers a new push with default channelName property
+	 * @param jsonData
+	 * @param eventName
+	 * @param socketId
+	 * @return
+	 */
+	public HTTPResponse triggerPush(String jsonData, String eventName, String socketId){	
+		return Pusher.triggerPush(channelName, eventName, jsonData, socketId);
+	}
+
+	public void setEventName(String eventName) {
+		this.eventName = eventName;
+	}
+
+	public String getEventName() {
+		return eventName;
+	}
+
+	public void setChannelName(String channelName) {
+		this.channelName = channelName;
+	}
+
+	public String getChannelName() {
+		return channelName;
+	}
+	
+}

README.md

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+Pusher Java classes for Google App Engine
+=========================================
+
+This Java classes can be used to communicate very easily with the Pusher REST API (http://www.pusherapp.com) from any Google App engine Web application.
+
+Get Started
+-----------
+Simply replace the Pusher specific constants in Pusher.java:
+
+	private final static String pusherApplicationId = "";
+	
+	private final static String pusherApplicationKey = "";
+	
+	private final static String pusherApplicationSecret = "";
+	
+Call one of the two available static methods called "triggerPush" and pass channel name, event name and the message body (JSON encoded data) as parameters:
+	
+	Pusher.triggerPush("test_channel", "my_event", jsonData);
+	
+The second "triggerPush" method provides an additional parameter for the socket_id:
+
+	Pusher.triggerPush("test_channel", "my_event", jsonData, socketId);
+	
+That's it.
+
+Default values
+--------------
+Sometimes it can be very convenient to prepulate a PusherRequest instance with default channel and/or event name:
+
+	PusherRequest p = new PusherRequest("test_channel","my_event");
+	
+To send a request to the Pusher API just call "triggerPush" on this instance:
+
+	p.triggerPush(jsondata);
+	
+License
+-------
+Copyright 2010, Stephan Scheuermann. Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php