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Archive for Programming

Dealing with CSS unit conversions in jQuery (px to em to percentages)

I spent some time working on a plugin to convert px to em and percentages for the upcoming Wordspot site.

The problem lies in the fact that measurements are based on the element they are attached to. Thus, to convert any CSS property (i.e. “5em” or “20%”) to pixels, one must determine what the relative height of a single line of text is in pixels.

This tool creates an invisible child element, measures a single line of text, and uses that for measurements.

Thus, to convert 90% (or any measurement, for that matter) to pixels, you could do the following:

?View Code JAVASCRIPT
   var borderRadiusPixels = $.UnitConverter.px( $('#mydiv').css('border-top-left-radius') );

Here’s the source.

For more advanced operations, you can do things like this:

?View Code JAVASCRIPT
   // create a new unit conversion
   var measurement = new $.UnitConverter( $('#mydiv') );
 
   // load a value to be examined
   measurement.load( $('#mydiv').css('border-left-width') );
 
   // add 10% to the height
   measurement.add( '10%' );
 
   // convert the measurement to various output types
   var pxs = measurement.px();
   var ems = measurement.convert( 'em' );
   var pct = measurement.convert( '%' );
 
   // determine what the measurement would be in another element (i.e. with a different line height)
   var clonePxs = measurement.clone( $('#nudderElement') ).px();

Hopefully this will give you a good head start on conquering similar issues, without having to invent any wheels!

Regular expressions tester for your regex fiddling

I was teaching a good friend a bit about regular expressions and wrote up a regular expression tester. It was a blast to write and simple to implement. It’s all in one HTML page so you can download it and fiddle away. Hope it helps someone else as well:

http://www.zenovations.com/blog/misc/regex.html

creating response headers

PHPWeby has a great article on how to create response headers for various means, such as 503, file download dialog, apache authentication, and so on.

http://phpweby.com/tutorials/php/35

 

 

Great JavaScript Regular Expressions reference

Covers all sorts of great JavaScript regular expressions details, like look ahead/behind assertions and ?: operator (for grouping without storing match).

http://www.javascriptkit.com/javatutors/redev2.shtml

XmlSchema best practices

Very nice article on best practices for structuring XmlSchema files:  http://www.xfront.com/ZeroOneOrManyNamespaces.html

Best support request subject evarr

Okay, it manages to still be searchable, informative, and yet is this funny:

So eclipse and xdebug walk into a bar, and then my apache server dies

Advanced Bash Scripting Guide

This guide really is a complete resource for understanding bash syntax; very easy to get around and understand.

http://tldp.org/LDP/abs/html/index.html

remote debugging PHP for a single virtualhost with PhpStorm and xdebug

I struggled for several days to set up remote debugging. I wanted to be able to remotely debug a single virtualhost on my CentOS server using my local IDE (PhpStorm) and xdebug.

Since this took me quite a while to figure out, I thought I’d include the steps here for others.

Installing Xdebug

Over SSH, I ran the following:

$ pecl install xdebug

Configuring Xdebug in php.ini

;;;;;;;;;;;;;;;;;;;
; Module Settings ;
;;;;;;;;;;;;;;;;;;;
zend_extension=/usr/lib/php/modules/xdebug.so
 
[xdebug]
xdebug.remote_enable=1
xdebug.remote_port=9000
xdebug.idekey=PHPSTORM-XDEBUG
xdebug.remote_connect_back=1
 
[Date]

Note the use of zend_extension; as of PHP 5.3, this is the only one that works (extension=…) will appear to function, but never connect!

Also, I used xdebug.remote_connect_back=1 – this allows connections from anywhere. But since I’ve configured my server to load a separate php.ini for each site (sorry, this is outside the scope of this discussion), and the entire site is under development and protected by .htaccess, I didn’t have to worry about other people debugging remotely.

An alternative to using remote_connect_back is to specify the remote_host to your local ip address:

xdebug.remote_host=0.0.0.0 ;your ip address
;xdebug.remote_connect_back=0

 Alternative: Loading via .htaccess instead of php.ini

Alternately, I could have dropped a .htaccess file into my root directory for the virtualhost, if the php.ini for each site were too much trouble:

php_value  zend_extension=/usr/lib/php/modules/xdebug.so
php_flag   xdebug.remote_enable on
php_value  xdebug.remote_port 9000
php_value  xdebug.idekey PHPSTORM-XDEBUG
php_flag   xdebug.remote_connect_back on

Configuring PhpStorm

I followed these instructions to the letter. Make sure you set up the “PHP Remote Debug” and not the “PHP Server” option if you’re using my list here as a guide (both work, I just chose the remote)

Remember to get those IDEKEY values to match up in the editor and on the server!

Configure Firewalls

On CentOS, I use apf, so I configured my firewall by adding port 9000 into the following settings: IG_TCP_PORTS, EG_TCP_PORTS

Then I restarted apf:

$ /etc/init.d/apf restart

At home, I opened a connection in my firewall by adding a redirect for port 9000 to my personal PC.

Starting it Up

Remember to reload Apache’s config!

$ /etc/init.d/httpd reload

Make sure PhpStorm is set to break on first line, or you won’t know if it worked! (you need the debugger to get involved):

 

Start the PhpStorm Remote Debug:

 

Make sure to click the “listen for connections” icon!

A quick note on semantics here: It is not technically necessary to have the debug server running and “listen for connections” clicked. Listen for connections will, in fact, start the debugger when an incoming connection is received. However, for initial testing, having the debugger actually ON was very helpful in being sure PhpStorm wasn’t failing to start incoming connections.

 

Connect to your IP address from the web server to make sure it can talk to your IDE:

$ telnet 0.0.0.0 9000

 

Add XDEBUG_SESSION_START=PHPSTORM-XDEBUG in the URL of the site to initiate a connection:

 

Witness debugging in all its glory!

 

Browser Plugins

There are browser plugins for Chrome and Firefox that make remote connections a breeze; you no longer have to type the parms into the URL. I’ve used both of these with success and highly recommend this simplification.

Flash cards for jQuery certification

I’ve been studying up for a jQuery certification.  I created a set of almost a thousand flash cards to prepare. I’ll be adding more for the jQuery UI in the near future.

This is a great site as once registered, you can check any number of the flash cards sets, then say “study 50″ or “study 100″ and it will give you a random cross section of the sets to study for the day. It tracks correct/incorrect and provides charting, as well as some other nice tools (keyboard navigation–yay!)

making Freeow work with jQuery 1.2.6

Hi,

I was able to make this lib work with jQuery 1.2.6 by making only this one-liner change:

?View Code JAVASCRIPT
    //this.element.hover(this.options.onHover); 
    this.element.hover(this.options.onHover, this.options.onHover);
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