Category Archives: programming

Example Mongrel2 Handler in Ruby

Right before I went to Rubyconf I started looking at Mongrel2 so I had something to hack on while I was there. I grabbed the two Ruby handlers listed on the main site, Ruby Mongrel2 and Rack Mongrel2, to get started. I noticed right away that I couldn’t kill the handler process once it started using either one of these libraries. I started down the path of figuring out why they wouldn’t respond to SIGINT and eventually to writing my own handler in Ruby that demonstrates how to fix the issue

Continue reading

Using Modernizr – Simple Guide and Examples

Modernizr is a Javascript library that detects the presence of browser functionality. This makes life a lot easier when using more modern features on your website by encapsulating all the feature tests into a library you don’t have to worry about. You can use Modernizr either in your own Javascript or you can use the CSS classes it sets on the HTML element.

To get a full list of the browser functionality that is tested check out the Modernizr docs. If the feature you need a test for isn’t available it is fairly easy to add new tests as well.

I’ll start with an example that shows how to use the feature tests in Javascript. After Modernizr runs it populates the “Modernizr” structure with boolean values for each functionality test. This example waits for the page to load and then simply populates a DIV with text depending on your browsers support for web sockets:

[code language=”html”]
<!DOCTYPE html>
<html class="no-js">
<head>
<title>Modernizr – Javascript Example</title>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js" type="text/javascript"></script>
<script src="modernizr.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function()
{
if (Modernizr.websockets)
{
$("#result").html(‘Your browser has support for Web Sockets’);
}
else
{
$("#result").html(‘Your browser does not support Web Sockets’);
}
});
</script>
</head>
<body>

<p id="result"></p>

</body>
</html>
[/code]

See this code in action: Modernizr Javascript example.

You can try this example with an older version of Firefox and the text should indicate that there is no support for web sockets. Try again with a newer version of Google’s Chrome browser and the page will indicate that there is support for web sockets.

The next example shows how to use the Modernizr CSS support. The key here is to know that the library will inject classes into the HTML tag. Those classes correspond to the functionality tests and are listed in the documentation. I am again testing for web sockets support and Modernizr will set the HTML class to either no-websockets or websockets and display one of two DIVs:

[code language=”html”]
<!DOCTYPE html>
<html class="no-js">
<head>
<title>Modernizr – CSS Example</title>

<style type="text/css" media="screen">
div.wsno, div.wsyes { display: none }
.no-websockets div.wsno { display: block }
.websockets div.wsyes { display: block }
</style>

<script src="modernizr.js" type="text/javascript"></script>
</head>
<body>

<div class="wsno">
Your browser does not support WebSockets.
</div>

<div class="wsyes">
Your browser supports WebSockets.
</div>

</body>
</html>
[/code]

See this code in action: Modernizr CSS example.

For a much more detailed CSS example check out this A List Apart article.

If you need the information Modernizr assembles outside of the browser check out Modernizr on the server.

While I was putting together the two demo pages for this I discovered a new service much like the Google Javascript library CDN but with more Javascript libraries. It is called Cached Commons and it uses Github’s CDN.

Getting Started with JRuby Webapps using Rack and Sinatra

Going to JRubyConf, hosted by some of the latest online casinos leading the internet world, inspired me enough to expand my knowledge of JRuby. This is a quick guide for anyone looking to see what can be done with JRuby and Sinatra.

Of course the first step is to install the Java JDK. Download, install and then set it up in your path. I’m using JDK 6 update 21 on Linux for this post in case it matters.

There are a couple ways to install JRuby after you have Java installed. The hard way is to download JRuby and install it by hand. The easy way is to use Ruby Version Manager to install it. Using RVM will let you switch between Ruby versions as well as giving you a simple command to install JRuby:

[code language=”text”]
rvm install jruby
rvm use jruby
[/code]

Continue reading

Using a HTTP Proxy to Debug JAX-WS and SOAP Over HTTPS

Every once in a while I run into something I need to debug from the network up. Most of the time I can do this using Wireshark but there are a few instances where what I’m really looking for is a man in the middle proxy. I usually find an alternative way to debug what I’m working on but recently I decided to find a combination that worked so the next time I can use it.

Most of the time what I’m working on when I need a proxy has something to do with SOAP and there is actually a MITM proxy in SoapUI but it doesn’t have support for HTTPS. If you are working with SOAP and can use HTTP then SoapUI is a great tool. If that doesn’t fit the bill then Paros proxy does a good job.

Continue reading

Faceted Search With Sphinx

I decided to use the Sphinx search engine for the GeeQe iPhone app I build last year because it was fast and had a very small memory footprint. Recently I wanted to experiment with a search interface that had facets and wondered if I would need to move away from Sphinx to something like Solr. As it turns out Sphinx can do faceted search almost as well as Solr can. The first half of what follows contains instructions on how to get Sphinx ready for faceted searches. If you are familiar with setting up Sphinx and already have data indexed by Sphinx you may find it better to skip to the second half after reading the intro to faceted search.

You have almost certainly seen faceted searching or faceted browsing already. A lot of online retailers now use facets in their online stores. Here are a few examples:

Continue reading

iPad Streaming Video and More

I’ve updated the configuration examples in the open source segmenter project to reflect Apple’s recommended stream bitrates for iPad video streaming, added a few fixes and a few new features. If you are interested in streaming video on the iPad, iPhone or iPod Touch and haven’t done so yet you it may help to start with my post on windowed streaming on for the iPhone, then read about iPhone HTTP streaming with FFMpeg and the open source segmenter and finally check out the iPad, iPhone, and iPod Touch live video streaming project page.

Here is a demo of the iPad streaming video created with the segmenter (I tried to show the progressive upgrade happening but it happens very quickly since the iPad is on WIFI, I also show that you can scrub without any issues and if you look in the background you can see the server log displaying entries as the segments are downloaded):

If you want to view the demo yourself I’ve created a demo for the iPad, iPhone, and iPod Touch. Note that those are two links, one for the iPad version and one for the iPhone/iPod Touch version. The main difference is the size of the video.

I used the open source video Big Buck Bunny (the 1920×1080 ogg version) for the above demos.

If you are interested in more details on what changed read on or skip to the bottom if you want to see what I’ll be working towards in future versions of the segmenter.

Continue reading

Using Cursors with PHP MySQLi and Multiple Prepared Statements

After my post on using PHP MySQLi and multiple prepared statements at the same time someone commented that using cursors could do the same thing. With that comment I dug some more and found that modifying the cursor type that is used under the covers will indeed let you execute multiple prepared statements concurrently on the same connection.

First off you may ask yourself why you would want to use this. The best answer I have for that is that the solution in the other post loads the entire result set into memory from the very start while with this solution you can control just how many rows you load. To get started you will want to take a look at the MySQLi statement set attribute call. This call is will let you modify the underlying cursor type that is used with the prepared statement in two ways that are useful for this issue.

Continue reading

Using Daemon-Kit and RobustThread to Build Ruby Daemons

On a number of occasions I have found myself needing to assemble a daemon process for some type or processing done using Ruby. Each time I roll things a little different and I finally started to wonder if someone had already put together tools for doing the daemon parts. After some quick digging I ran into Daemon-Kit and after adding it together with a couple other tools it seems like what I’ve needed. I’ve put together a few recipes here to help guide others who might be looking for something similar.

Continue reading

Building HipHop PHP for Fedora 12 on 64 bit and 32 bit Systems

Now that Facebook has finally released the source for HipHop PHP it is time to give it a spin. Of course it is still a little rough around the edges so I figured I would toss together a quick howto on getting it to build.

The first thing to note is that they are only supporting 64 bit systems officially. Having said that it isn’t too hard to modify the code to make it work on a 32 bit system although it may turn out that such early modifications are missing some fundamental bits on why they were only support 64 bit systems. I’m going to assume at first that you are using a 64 bit system and then end with what you need if you are still using a 32 bit system.

Continue reading