Following up on my previous post about Tracking External links with Google Analytics. Here’s something you can use to track Facebook likes and shares.

We’ll track clicks using the Facebook Events. Note that this only works if you’re using FBML!
Here’s the things we’re going to be tracking:

• Somebody clicks the ‘Like’ button on your website to ‘Like’ your Facebook page
• Somebody clicks the ‘Like’ button on your website to share the current page on his ‘Wall’
• Somebody clicks the ‘Send’ button to share this page with some friends on Facebook

And it’s all in here:

FB.Event.subscribe("edge.create",function(response){
	if(response.indexOf("facebook.com") > 0){
                 //if the returned link contains 'facebook,com'. It's a 'Like' for your Facebook page
		_gaq.push(['_trackEvent','Facebook','Like',response]);
	}else{
                 //else, somebody is sharing the current page on their wall
		_gaq.push(['_trackEvent','Facebook','Share',response]);
	}
});
FB.Event.subscribe("message.send",function(response){
	_gaq.push(['_trackEvent','Facebook','Send',response]);
});

As you may have noticed, the Facebook event contains the liked/shared/sent link as response

Outgoing links on your websites cause 3 things:

• Take linkjuice away from your page
• Drive traffic away from your webiste
• They don’t allow you to measure the amount of clicks on that link

The first problem, you have to sort manually by adding the rel=”nofollow” attribute to all external links, as recommended by Google.

The second and third problem, can be easily fixed by using jQuery. I’ll show you how:

Opening external links in a new tab

By opening those links in a new tab, your page stays open, therefore not driving the user away from your page.
Normally, this is done by manually appending target=”_blank” to each link. Let’s let jQuery do that for us.

$(document).ready(function(){
    $("a[@href^='http']").attr('target','_blank');
});

(Do note that I chose to define links starting with ‘http’ as external links)

Tracking clicks on external Links

We can track links by using Google Analytics Event tracking:

$(document).ready(function(){
    $("a[@href^='http']").click(function(){
        _gaq.push(['_trackEvent', 'External Link','Click', $(this).attr("href")]);
    });
});

Putting it all together

$(document).ready(function(){
    $("a[@href^='http']")
        .attr('target','_blank')
        .click(function(){
            _gaq.push(['_trackEvent', 'External Link','Click', $(this).attr("href")]);
        });
});

Help! My internal links also start with ‘http’

No problem, you can do like me and borrow this trick from Karl Swedberg:

$('a').filter(function() { return this.hostname && this.hostname !== location.hostname; })
.attr('target','_blank')
.click(function(){
    _gaq.push(['_trackEvent', 'External Link','Click', $(this).attr("href")]);
});

Google provided a few translation bots recently.
Since I do a lot of Dutch -> French translation, I quicly whipped up my own and deployed it to Google AppEngine:

For translating I used the unofficial google-api-translate-java jar file.
Here’s what you need to do:

Place the jar in war\WEB-INF\lib

war\WEB-INF\web.xml

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
	<servlet>
		<servlet-name>Translate_Bot</servlet-name>
		<servlet-class>be.bartv.translatebot.Translate_BotServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>Translate_Bot</servlet-name>
		<url-pattern>/translate_bot</url-pattern>
	</servlet-mapping>
	<servlet>
		<servlet-name>xmppreceiver</servlet-name>
		<servlet-class>be.bartv.translatebot.XMPPReceiverServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>xmppreceiver</servlet-name>
		<url-pattern>/_ah/xmpp/message/chat/</url-pattern>
	</servlet-mapping>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
	</welcome-file-list>
</web-app>

war\WEB-INF\appengine-web.xml

<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
	<application>translate-bot</application>
	<version>1</version>
 
	<!-- Configure java.util.logging -->
	<system-properties>
		<property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/>
	</system-properties>
	<inbound-services>
    	<service>xmpp_message</service>
  	</inbound-services>
 
</appengine-web-app>

src\be.bartv.translatebot.XMPPReceiverServlet.java

package be.bartv.translatebot;
 
import java.io.IOException;
 
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.google.api.GoogleAPI;
import com.google.api.translate.Language;
import com.google.api.translate.Translate;
import com.google.appengine.api.xmpp.JID;
import com.google.appengine.api.xmpp.Message;
import com.google.appengine.api.xmpp.MessageBuilder;
import com.google.appengine.api.xmpp.XMPPService;
import com.google.appengine.api.xmpp.XMPPServiceFactory;
 
public class XMPPReceiverServlet extends HttpServlet{
	private static final long serialVersionUID = 2212159648921332999L;
	public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException
	{
		XMPPService service = XMPPServiceFactory.getXMPPService();
		Message message = service.parseMessage(req);
		JID jid = message.getFromJid();
		String content 	= message.getBody();
 
		String reply = "Hmmz. I Should return a translation now";
		try {
			GoogleAPI.setHttpReferrer("http://notes.bartv.be/");
			reply = Translate.execute(content, Language.DUTCH, Language.FRENCH);
		} catch (Exception e) {
			reply = "Error occurred: "+e.getMessage();
			e.printStackTrace();
		}
		service.sendMessage(new MessageBuilder().withBody(reply).withRecipientJids(jid).build());
	}
}

Sometimes, I do get a error saying I violate Google’s Terms and conditions. No idea why tho …

Google sometimes shows breadcrumbs in their search results.
Instead of showing the URL of the page you’re going to visit (in the green bit), hey’ll show a path kind of like so:
Homepage › Category › Subcategory > Something something.
Many SEO experts have been trying to figure out just where they come from. So have I.
So recently, on one of my websites: promoties.be. I had the chance to figure it out.

All promotions are divided into categories and subcategories. The URL of these categories are always hierarchically mapped.
e.g. http://www.promoties.be/categorie/autos-motoren-27/aanhangwagens-1419 is a subcategory of http://www.promoties.be/categorie/autos-motoren-27 making the URL logically traversable.
However a specific offer or product under this category is not in this structure. Mainly because that would make the URL way too long.
An example is http://www.promoties.be/promotie-bw1-aanhangwagen-864809. As you can see, the categories do not appear in the URL.

However the breadcrumb for this offer is as follows: Home > Promoties > Auto’s & Motoren > Aanhangwagens > Bw1 aanhangwagen with all the nested categories intact.

Now the Google search result block for this specific offer was the following:

Google search result for "Bw1 aanhangwagen"

In this case we can conclude that Google took the breadcrumbs in the search results, from the breadcrumbs on the page.

More info on breadcrumbs:

http://www.google.com/support/webmasters/bin/answer.py?answer=185417

I recently stumbled upon an article on Six Revisions titled Are Current web design trends pushing us back to 1999?.

I found it to be a very interesting article. It mainly talks about how new trends in the web are barking up old problems, like the Flash splash page, or the shoutbox.

On thing I found very interesting was the part called Modern-Day Bloated, Cut-And-Paste Scripts.

Being involved with jQuery on a day-to-day basis, you start using some plugins, or even write some of your own.
But once you start stacking plugins, the browser has to load all of these plugins, generating more request. Which is generally a good idea.

Now whenever creating a new webproject, I use one JS file: lib.js. This JS file contains everything I need, it’s like a swiss pocket knife!
Structure is usually like following (depends on your project needs):

• jQuery
• jQuery UI
• Plugins
• $(document).ready(function(){ /**magic here **/});

You could argue by saying: but doesn’t the filesize increase by a lot, letting the user download a 250k file is quite a lot!
I agree, but play your cards right in server configuration with a little help from Google’s mod_pagespeed or simply by getting goot ETags or Expires headers, the load happens just once (!!). And the rest of your surfing experience stays snappy.

Recently I discovered Internet Explorer caches some AJAX calls.

I was using jQuery to make some AJAX calls in a web-admin interface I’m building. I noticed none of the data changed as I tried to refresh (using an AJAX call). conclusion:: IE caches AJAX calls… very annoying.

You could go around and alter every method in your Struts/Spring/… application to force no-cache. But that would take some time. Instead, I wrote a Filter.

Hold on though, you don’t want every page to get the no-cache headers, that would seriously decrease your site performance (all pages would be force-reloaded instead of browser-cached). So we’ll only filter out AJAX calls.

Luckily, jQuery passes a header argument: X-Requested-With: XmlHttpRequest

X-Requested-With

The Code!

import java.io.IOException;
 
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class AjaxCacheFilter implements Filter{
 
	@Override
	public void destroy() {
	}
 
	@Override
	public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {
		if ("XMLHttpRequest".equals(((HttpServletRequest) request).getHeader("x-requested-with"))) {
			((HttpServletResponse)response).setDateHeader("Expires", 0);
			((HttpServletResponse)response).addHeader("Cache-Control", "no-cache");
			((HttpServletResponse)response).addHeader("Pragma", "No-Cache");
 
		}
		chain.doFilter(request, response);
	}
 
	@Override
	public void init(FilterConfig arg0) throws ServletException {
	}
}

And add it as the last filter in your web.xml

<filter>
	<filter-name>ajaxCache</filter-name>
	<filter-class>
		com.yoursite.web.filters.AjaxCacheFilter
	</filter-class>
</filter>
<filter-mapping>
	<filter-name>ajaxCache</filter-name>
	<url-pattern>/*</url-pattern>
 	<dispatcher>FORWARD</dispatcher>
		<dispatcher>REQUEST</dispatcher>
</filter-mapping>

Hope it helps somebody! If you used it, let me know in comments. I’d love to know!

Whats the problem?

Maybe you’ve made a deal with a partner website, or you’re just loading a page from another server. The point is: You’ve got an IFrame on your page coming from another domain.
All is well (except for Google, they don’t like iframes) untill you want some client-side interaction coming from that page.

But now you’ve reached the point where you want some client-side interaction from that IFrame. “Great!” you say. I’ll just put JS in the IFrame, and I’ll be fine. But hold your horses cowboy, there’s 2 things stopping you as a great developer from doing so:

• Don’t have you JS scattered, have it nice and organised, centralized
• You’re visually constrained to the IFrame

So how do we execute JS on the parent frame?

Directly from the IFrame? You can’t! Sandbox specifications say you can’t call functions defined in pages coming from another domain (kind of like loading JSON/Ajax from another domain).

But in that problem also lies the solution: just load a Proxy page from the other server!
Let me make myself a bit more clear through some Graphs:

Normally, you’de have 2 pages, page A contains an Iframe to page B:

Now we’re introducting a Proxy page, on the same server as page A. Page B contains a IFrame to the proxy page:

All Done! Now you can execute JS, like so:

The Code!

So how do we do it? Here you go!
index.html (on your server)

<html>
	<head>
		<script type="text/javascript">
			function alertme(str)
			{
				alert("String: " + str);
			}
		</script>
	</head>
	<body>
		<iframe src="http://yourpartner.com/iframe.htm"></iframe>
	</body>
</html>

proxy.html (on your server)

<html>
	<head>
		<script type="text/javascript">
			function gup( name )
			{
			  name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
			  var regexS = "[\\?&]"+name+"=([^&#]*)";
			  var regex = new RegExp( regexS );
			  var results = regex.exec( window.location.href );
			  if( results == null )
			    return "";
			  else
			    return results[1];
			}
			eval("top."+gup("execute"));
		</script>
	</head>
</html>

And finally!
iframe.html (on any other server)

<html>
        <head>
        </head>
        <body>
        Hi There!
        <iframe src="http://yourserver.com/proxy.html?execute=alertme(123);"></iframe>
        </body>
</html>

What you did there, I don’t quite see it

In the page on the other server, I pass a function call as an argument to my proxy.
My proxy then gets this function out of the parameter, and executes it through eval()!

Warning

Handle with care, allowing anyone to simply execute JS on/from your server through a parameter just opens up a whole new spectrum of XSS attacks.
That sandbox was created for a reason!

Google recently released a specific Apache mod: mod_pagespeed.
Here are my findings:

Introduction: goal

Often, when developing websites/webapplications, you find yourself telling yourself: I’ll quickly write that piece of CSS inline or Fudge it, I’ll leave compressing that piece of JavaScript for when I get out of development phase and maybe even never mind resizing that image, I’ll just use ‘width’ and ‘height’ to get the dimensions right.
And oh how you promise yourself you’ll fix those issues later. But let’s be honest: deadlines are cruel.

So a lot of websites go live without a lot of speed omtimizations. They get a bad score in YSlow or PageSpeed.
And the word on the street is, google prefers website that load faster!

Optimizing your CSS/JS/Images takes time. Compressing your content, combining CSS/JS also makes it difficult to adjust any of these later. You’ll have to dig through compacted code. Nobody likes that.

The solution

The new mod_pagespeed is an Apache Output Filter. This means your website renders your website (in PHP, Java, Ruby, …) and just before Apache serves your HTML page to the browser, this thing comes into action.

You can configure it to do a lot of things. I listed the ones I find most important below. But you can get the full feature list here

• Compress CSS and JS (less traffic)
• Move inline CSS/JS to an external file (so they can get cached)
• Combine external CSS/JS to one file (less requests)
• Caching (of HTML,CSS,JS,images)
• Automatically resize images based on the ‘width’ and ‘height’ attributes of an img-tag (less traffic)
• Add ‘width’ and ‘height’ attributes if you forgot any (usability)
• Base64 encode images and include them in HTML when small (less requests)

Bottomline: it’s genius

My Configuration

I played around with mod_pagespeed today. Here’s the configuration I came up with (I added comments)
(your configuration resides in /etc/apache2/mods-enabled/pagespeed.conf)

<IfModule pagespeed_module>
	ModPagespeed on
	AddOutputFilterByType MOD_PAGESPEED_OUTPUT_FILTER text/html
 
	ModPagespeedFileCachePath            "/var/mod_pagespeed/cache/"
	ModPagespeedGeneratedFilePrefix      "/var/mod_pagespeed/files/"
 
	ModPagespeedRewriteLevel CoreFilters
 
 
	ModPagespeedFileCachePath            "/var/mod_pagespeed/cache/"
	ModPagespeedGeneratedFilePrefix      "/var/mod_pagespeed/files/"
	#Add head section to HTML (if not already there)
	ModPagespeedEnableFilters add_head
	#Move CSS and JS to outline (external file)
	ModPagespeedEnableFilters outline_css,outline_javascript
	#If inline CSS is used, move this to head section
	ModPagespeedEnableFilters move_css_to_head
	#Combine external CSS files to 1 fil
	ModPagespeedEnableFilters combine_css
	#Compress CSS and JS by removing whitespace/comments
	ModPagespeedEnableFilters rewrite_css,rewrite_javascript
	#Cache/compress images. Couold also move the image to  HTML code (base64 encoded) if image size is small enough
	ModPagespeedEnableFilters rewrite_images
	#Add longer expires headers
	ModPagespeedEnableFilters extend_cache
	#Insert "width" and "height" attributes if not used
	ModPagespeedEnableFilters insert_img_dimensions
	#Remove HTML comments
	ModPagespeedEnableFilters remove_comments
	# Removes quotes around HTML attributes that are not lexically required
	ModPagespeedEnableFilters remove_quotes
 
	#pagespeed enabled domain 1
	ModPagespeedDomain tv.bartv.be
	#Pagespeed enabled domain 2
	ModPagespeedDomain cloudcast.bartv.be
	#pagespeed enabled domain 3
	ModPagespeedDomain notes.bartv.be
 
	#Maximum filesize cache
	ModPagespeedFileCacheSizeKb          10240
	#Interval to which cache is refreshed
	ModPagespeedFileCacheCleanIntervalMs 3600000
	ModPagespeedLRUCacheKbPerProcess     1024
	ModPagespeedLRUCacheByteLimit        16384
	#Minimum allowed bytes in CSS before exporting to external CSS
	ModPagespeedCssOutlineMinBytes       1000
	#Minimum allowed bytes in JS before exporting to external JS
	ModPagespeedJsOutlineMinBytes        3000
        #Maximum allowed filesize for embedding images inline (base64)
        ModPagespeedImgInlineMaxBytes        2048
 
</IfModule>

Carefull with writing permissions

On my webserver, I run every website under a different user account (e.g. mycoolwebsite.bartv.be is run by user ‘coolwebsite’ or something). They all belong to the group ‘www-data’.
Now one consequence of this is that the cache being written by mod_pagespeed gets written by the user running the website. So be carefull with writing permissions in /var/mod_pagespeed/

Footnote

Even though this article might suggest it. I’m in no way promoting quick and dirty development.
You could think: to hell with it, I’ll just write whatever I want, mod_pagespeed will solve it for me. Don’t

mod_pagespeed is great, but in my eyes, it helps you find errors you might have missed. And it lets you use your development CSS/JS files without compressing them first.
But don’t use it to clean up your mess!

Recently, I came to the conclusion that the beautifull service of Mixcloud was missing a really cool feature: podcasting.

They have som really cool artists posting music on there, and I enjoy listening to mixcloud sets every day at work. But there’s just no possibility for me to take these with me in my car (as in: on my iPod).

To fix this, I developed a small service called CloudCast. It was simple, just enter the username of your favorite artist on Mixcloud and you would be redirected to a page that gave an overview of this artist’s recent mixes, and gave you an RSS/Podcast link for your favorite music player.
All was good, … for about 17 hours.

I got contacted by @matclayton on Twitter the asking me to contact him.

We had some email communication. But in the end it boiled down to this:
Mixcloud has to pay artists royalties for every time a user listens to a mix. This is also why a mix is divided into tracks, so the respective artist is paid the respective amount. Whenever you download a track to your computer, there are 2 problems:

• they don’t know how many times you play it
• just having the file on your computer violates copyrights

So I had to close the website (which kind of sucks, it drove a lot of traffic to my site!)
Mixcloud are soon to change the way their API works, so API-sniffing people like me can’t make cloudcast services that allow a user to download the MP3′s.
So the problem should be solved soon anyway.

However, knowledge is free. So I’m here to share what I’ve learn’t from their API.

Step 1: getting the user’s mixes

The URL you’re going to want to use is

http://api.mixcloud.com/[username]/cloudcasts/

This gives you a JSON result. For every ‘Cast’ they give you, they give you a slug. You’re going to use this slug.

Tip: You can use the parameter ‘limit’ to define how many results you want. (e.g. ?limit=50)

Step 2: getting Cast information

This one uses a different API I guess:

http://www.mixcloud.com/api/1/cloudcast/[username]/[slug].json

Also returns JSON

This gives you, somewhere in the API a variable called ‘mp3_urls’ ‘audio_formats’.
Jackpot! I hear you think. And you’d be right. However Mixcloud gives you 4 url’s. They don’t always seem to work all 4. So keep in mind you want to check those URL’s for 404′s

Step 3

Enjoy API hacking

Update: I am now thinking of developing an Android application for the same purpose. This ‘kind of’ downloads the mixes to your Android device aswell. But if the kind people of Mixcloud could provide me with an API functionality so a developer could say: “I’m now listening to Mix A from artist XYZ”. That would solve all problems… I guess

About SOLR

SOLR is a great search server, written under the Apache license.
This means 2 things: it’s free and supported by a great community of experts!

It’s important to know that SOLR consists of 2 parts:

• The solr server: a standalone Java application that handles data management and searching
• The solr web applicaton: provides web services and handles requests. Deploy this to Tomcat, or use the integrated Jetty

Also, solr provides a Java interface called SOLRj.
SOLRj provides 2 ways of connecting to your SOLR server:

• EmbeddedSolrServer connects directly to your SOLR server core and omits the web application
• CommonsHttpSolrServer connects to the SOLR web app

Now I hear you thinking: why would I go via the Web App when I can connect directly to the core?
The answer is simple: distributed servers. Imagine your web application is divided among multiple servers in order to balance the load, you can’t connect to the SOLRCore, unless you use multiple solr instances (which I don’t at the moment).

The Problem

So we’re using the SOLR web app on 1 server, and we use it’s webservices.
However, we don’t really want to leave it nice and open so any scriptkiddie can just connect to http://yourprettysolrserver.com/solr/admin/. So we use Basic HTTP authentication (I know, still not very secure. But the communication will only happen between the 2 virtual servers, so no chance of a Man in the Middle attack).
On notes how to secure your SOLR via basic auth, visit the SolrSecurity Wiki page.

The Solution

SolrJ uses Apache’s
So doing it in Java should go in a jiffy(as described here).

My solution was a bit quick, and maybe a bit dirty, but it works!
I made a subclass of HttpClient:

public class BasicAuthHttpClient extends HttpClient {
	public BasicAuthHttpClient()
	{
		super();
	}
	public BasicAuthHttpClient(String username, String pass)
	{
		super();
		Credentials creds = new UsernamePasswordCredentials(username,pass);
		this.getState().setCredentials(AuthScope.ANY, creds);
		this.getParams().setAuthenticationPreemptive(true);
	}
}

There’s a constructor that simply takes a username and password as argument.
In my ApplicationContext, I defined the following:

<bean id="solrHttpClient" class="com.example.system.utility.BasicAuthHttpClient">
	<constructor-arg value="${solrserver_user}" />
	<constructor-arg value="${solrserver_pass}" />
</bean>
<bean id="httpSolrServer" class="org.apache.solr.client.solrj.impl.CommonsHttpSolrServer">
	<constructor-arg value="${solrserver_path}" />
	<constructor-arg ref="solrHttpClient" />
</bean>

Works like a charm here! And should be thread safe.
Hope it helps somebody