The Codr.Eu Podcast

Myself, Phil Sturgeon and Adam Griffiths will be doing a podcast within the next few weeks, just to push out some content. We’ll also be looking to interview people, our main focus will be coding with CodeIgniter though. The point of the Podcast is for people to submit questions and have us answer them also for ourselves to give you guys updates on what’s going on within the coding world, so you could say coding news too. Also little tips and tricks (I’m sure Phil will rant on about his REST implementations alot ) anyway, just thought I would let you all know that there will be a podcast soon, and possibly! A new design for Codr when I get around to it… It’ll probably be Blue and Black like my current layout, but more tutorial site based

To quote the PHP Manual “References in PHP are a means to access the same variable content by different names.” which I believe is a perfect explanation.  So, If you pass by reference instead of making a copy you are modifying the original variable. This is done by placing a single “&” (ampersand) in front of the variable you are assigning.

The concept sounds a little strange at first, but lets take a look at the example.

<?php
// Create a variable.
$original_variable = 1;

// Create a reference to $original_variable
$ref_variable =& $original_variable;

// Increment $ref_variable by 10
$ref_variable += 10;

// Output $original_variable
echo $original_variable; // Outputs "11"

// Decrement $original_variable by 5
$original_variable -= 5;

// Output $ref_variable
echo $ref_variable; // Outputs "6"

?>

I know what you are thinking… “what the hell?!” right? Ok, lets take that one a little slower.

// Create a variable.
$original_variable = 1;

Just making avariable.

// Create a reference to $original_variable
$ref_variable =& $original_variable;

$ref_variable is now a “clone” or reference of $original_variable. Any modifications made to either will reflect in both variables as they are essentially the same variable with different names. The one exception to this rule is deleting. If you delete $ref_variable, $original_variable will still exist.

// Increment $ref_variable by 10
$ref_variable += 10;

// Output $original_variable
echo $original_variable; // Outputs "11"

This line will add 10 to $ref_variable which of course means the value of $original_variable will go up by 10.

// Increment $original_variable by 10
$original_variable -= 5;

// Output $ref_variable
echo $ref_variable; // Outputs "6"

Finally we have a similar block of code. The purpose of this was to demonstrate that you can modify either variable to change them both. Changes to the $original_variable will reflect in $ref_variable as soon as they are made.

One thing to remember is that you can only create references to variables. That means any static strings, ints, floats, etc will throw an error.

<?php
// Try and create a new reference:
$ref_variable =& 10;
?>

That code will throw a syntax error like “Parse error: syntax error, unexpected T_LNUMBER, expecting T_NEW or T_STRING or T_VARIABLE or ‘$’”, to correct it the value should first be assigned to a variable and then a reference made to that variable.

There are plenty more uses for references, i’ll explain how to use them in foreach loops in the next post.

Expressions

Detect URL’s

 '|([a-z]{3,9}://[a-z0-9-_./?&+]*)|i' => '<a href="$0" target="_blank">$0</a>', 

Detect E-mail addresses

 '|[a-z0-9._%+-]+@[a-z0-9.-]+.[a-z]{2,6}|i' => '<a href="mailto:$0">$0</a>', 

Detect @usernames’s

 '|@([a-z0-9-_]+)|i' => '<a href="http://twitter.com/$1" target="_blank">$0</a>', 

Detect #tags

 '|#([a-z0-9-_]+)|i' => '<a href="http://twitter.com/search?q=#$1" target="_blank">$0</a>' 

Example

Lets put this together to create a very simple working example.

<?php
// Fetch the Tweets in JSON form and convert to a PHP object
$tweets = json_decode(file_get_contents('http://twitter.com/statuses/user_timeline/philsturgeon.json?count=10'));
// List all regular expression rules
$patterns = array(
			'|([a-z]{3,9}://[a-z0-9-_./?&+]*)|i'		=> '$0', // Detect URL's
			'|[a-z0-9._%+-]+@[a-z0-9.-]+.[a-z]{2,6}|i'	=> '$0', // Detect Email Addresses

			'|@([a-z0-9-_]+)|i'	=> '$0', 			// Detect Twitter @usernames
			'|#([a-z0-9-_]+)|i'	=> '$0'	// Detect Twitter #tags
			);

// Loop through tweets
foreach($tweets as $tweet)
{
	// Run all rules to replace syntax with HTML
	$tweet->text = preg_replace(array_keys($patterns), array_values($replace), $tweet->text); 

	// Display the tweet with syntax enabled
	echo '

'.date('d/m/Y', strtotime($tweet->created_at)) . ' ' . $tweet->text.'

';
}
?>

This is not following perfect coding practices, it will not cache data and might not be the most optimal implementation but I was trying to keep the amount of code low to show the simplicity of how it can be achieved.

Instead of showing a users timeline you can use the same code to show search results with the url:

http://search.twitter.com/search.json?q=pyrocms

Now, go forth and tweet!

The Video

Part One

Part Two

The Code / Explaination

index.php – The Code

<html>
	<head>
		<title>jQueryness</title>

		
		


	

jQueryness

			
			
				box1 |
				box2 |
				box3
			
			

				Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent vel massa massa, sit amet laoreet elit. Praesent porttitor pharetra dui,
				quis fringilla justo luctus ac. Duis convallis, dui non facilisis mollis, ipsum diam sodales nisl, vel tincidunt ipsum augue vel lacus.
				Fusce a urna eu lectus mattis placerat. Vestibulum eget urna quis sem rhoncus blandit in vel massa. Nullam in tortor eget sem rhoncus
				consequat vel nec metus. Maecenas vehicula, diam vitae dictum blandit, ante mauris faucibus orci, id ornare erat ligula ac arcu. Nulla
				facilisi. Suspendisse imperdiet feugiat eros, porta lacinia nibh consectetur at. Lorem ipsum dolor sit amet, consectetur adipiscing elit.
				Suspendisse et felis lorem. Praesent vitae nulla risus, eu rhoncus quam.
			

				Praesent eget nisl sed sem cursus semper. Donec ut elit a orci feugiat vulputate. Integer posuere sagittis lobortis. Integer pulvinar dictum libero.
				Integer ac velit quam, id dapibus felis. Vestibulum tempor aliquet ligula euismod accumsan. Etiam dapibus ultricies orci, vitae consequat purus venenatis
				vel. Curabitur vestibulum massa ac nisl venenatis posuere. Curabitur dictum metus eget velit congue fermentum. Duis quis quam in urna sollicitudin egestas
				ut vel urna. Suspendisse bibendum sodales pulvinar. Sed a quam nisl, non lacinia erat. Duis pellentesque tincidunt scelerisque. In sed felis at arcu tristique
				semper nec et purus. Ut suscipit semper accumsan. Curabitur tempor sem nec sapien suscipit porta. Donec eget urna nunc, ac bibendum nunc. Quisque congue pellentesque
				arcu nec aliquet. Morbi in mi eget ipsum egestas sagittis.
			

				Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent vel massa massa, sit amet laoreet elit. Praesent porttitor pharetra dui,
				quis fringilla justo luctus ac. Duis convallis, dui non facilisis mollis, ipsum diam sodales nisl, vel tincidunt ipsum augue vel lacus.
				Fusce a urna eu lectus mattis placerat.
			


	</body>
</html>

index.php – The Explaination

Okay lets get down to the explaination of index. First we declared the DOCTYPE of

< !DOCTYPE HTML>

we do this so that W3C can validate your page and so that it knows automatically what version of HTML you’re rusing. This doctype is mainly for HTML5. After that we then opened up our html, head and title tags and inserted the title of jQueryness we then referenced the jquery-1.3.2.min.js from Google Code and our function.js file with

We then closed off our head then opened our body and inserted a new div with the id of wrapper, this is the element which stands out with its CSS3 Specification Drop Shadow

...

after opening the wrapper we decided to put in a heading with our main title in then opened a code tag so that we can link our content boxes with:

box1 |
box2 |
box3

then finally we created our content boxes with the classes of box1, box2, box3 with the following:

...


...


...

style.css – The Code & Explaination (in comments)

/*
 * Define the MAIN background colour, default margin, fonts
 * text colour etcetera.
 */
body {
	background-color: #efefef;
	margin: 40px auto;
	font: 10pt "Lucida Grande", "Trebuchet MS", sans-serif;
	color: #777777;
}

/*
 * Make the wrapper look pretty, center it on the page, make sure
 * that it's no thicker than 500 pixels with some padding, let it have
 * a nice subtle solid dark gray border with a drop shadow
 * 3 pixels from the right, 3 pixels from the bottom and 1 pixel in weight
 * with another subtle gray.
 */
#wrapper {
	margin: 0 auto;
	background-color: #ffffff;
	border: 1px solid #bababa;
	width: 500px;
	padding: 0 15px 10px 15px;
	-moz-box-shadow: 3px 3px 1px #dadada;
	-webkit-box-shadow: 3px 3px 1px #dadada;
}

/*
 * Set a the main font to be a fixed width font such as Monaco
 * with the background of off white, border of dark gray, and font
 * colour of black. Set the margins 14 pixels from the top and bottom
 * Provide a little bit of padding as well so the content looks nice.
 */
code {
	font: 12px Monaco, "Lucida Console", small-fonts;
	background-color: #f9f9f9;
	border: 1px solid #D0D0D0;
	color: #000000;
	display: block;
	margin: 14px 0 14px 0;
	padding: 12px 10px 12px 10px;
}

/*
 * Set the main content boxes display
 * to none so that they're hidden on
 * page load.
 */
.box1, .box2, .box3 {
	display: none;
}

function.js – The Code & Explaination (in comments)

/*
 * When the document is ready then hide box2 and 3 but show box1.
 */
$(document).ready(function() {
	$("div .box1").show();
	$("div .box2").hide();
	$("div .box3").hide();

/*
 * If the link with the id of navItem is clicked then make
 * relevent box slide down in the duration of 0.6 seconds.
 * Also ensure that the other boxes are hidden.
 */
	$("#navItem1").click(function() {
		$("div .box1").slideDown(600);
		$("div .box2").hide();
		$("div .box3").hide();
	});

	$("#navItem2").click(function() {
		$("div .box2").slideDown(600);
		$("div .box1").hide();
		$("div .box3").hide();
	});

	$("#navItem3").click(function() {
		$("div .box3").slideDown(600);
		$("div .box2").hide();
		$("div .box1").hide();
	});

});

The Download

jQueryness.zip

Final Words

Thank you for reading this tutorial and I hope that you find it quite useful, if you have any questions please don’t hesitate to leave a comment below when the comments get enabled, If they still aren’t enabled then please email webmaster [ at ] paulchater.co.uk

To get this working I took a little code from PyroCMS and modded a previous article “How to: Support multiple production environments in CodeIgniter” and found a relatively simple solution.

Setting the base URL

The first step of getting CodeIgniter working anywhere automatically is curing it of it’s most pointless configuration setting. It seems CodeIgniter would like to be told where it is, which really doesn’t need to happen. We could solve this in many ways, but instead of extending or replacing any core code, I would preffer to put a little snippet of code into the main application/config/config.php. Enter this code into the file and it will automatically support pretty much any kind of URL.

/*
|--------------------------------------------------------------------------
| Base Site URL
|--------------------------------------------------------------------------
|
| URL to your CodeIgniter root. Typically this will be your base URL,
| WITH a trailing slash:
|
| http://www.your-site.com/
|
*/

if(isset($_SERVER['HTTP_HOST']))
{
$config['base_url'] = isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on' ? 'https' : 'http';
$config['base_url'] .= '://'. $_SERVER['HTTP_HOST'];
$config['base_url'] .= str_replace(basename($_SERVER['SCRIPT_NAME']), '', $_SERVER['SCRIPT_NAME']);
}

else
{
$config['base_url'] = 'http://localhost/';
}

Setting a SITE constant

So the website URL is now set and links are fully working around the site. Next we need a way to work out throughout our code which site is currently being used. Amongst other things, this will help us with selecting the right database settings later.

/*
|--------------------------------------------------------------------------
| Site
| Set a constant for whichever site you happen to be running, if its not here
| it will fatal error.
|--------------------------------------------------------------------------
*/
switch($_SERVER['HTTP_HOST'])
{
case 'example.com':
case 'www.example.com':
define('SITE', 'example');
break;

case 'example2.com':
case 'www.example2.com':
define('SITE', 'example2');
break;

default:
define('SITE', 'default');
break;
}

Domain based database settings

Now that CodeIgniter has its links working and it knows what site it is trying to run, it needs to know the database configuration for this domain. To do that, we can break down our config into domain specific “Database groups”.

< ?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
/*
| -------------------------------------------------------------------
| DATABASE CONNECTIVITY SETTINGS
| -------------------------------------------------------------------
| This file will contain the settings needed to access your database.
|
| For complete instructions please consult the "Database Connection"
| page of the User Guide.
|
| -------------------------------------------------------------------
| EXPLANATION OF VARIABLES
| -------------------------------------------------------------------
|
| ['hostname'] The hostname of your database server.
| ['username'] The username used to connect to the database
| ['password'] The password used to connect to the database
| ['database'] The name of the database you want to connect to
| ['dbdriver'] The database type. ie: mysql.  Currently supported:
     mysql, mysqli, postgre, odbc, mssql
| ['dbprefix'] You can add an optional prefix, which will be added
|     to the table name when using the  Active Record class
| ['pconnect'] TRUE/FALSE - Whether to use a persistent connection
| ['db_debug'] TRUE/FALSE - Whether database errors should be displayed.
| ['active_r'] TRUE/FALSE - Whether to load the active record class
| ['cache_on'] TRUE/FALSE - Enables/disables query caching
| ['cachedir'] The path to the folder where cache files should be stored
|
| The $active_group variable lets you choose which connection group to
| make active.  By default there is only one group (the "default" group).
|
*/

$active_record = TRUE;

$db['default']['hostname'] = "localhost";
$db['default']['username'] = "";
$db['default']['password'] = "";
$db['default']['database'] = "";
$db['default']['dbdriver'] = "mysql";
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";
$db['default']['dbcollat'] = "utf8_general_ci";

// example
$db['example']['hostname'] = "localhost";
$db['example']['username'] = "root";
$db['example']['password'] = "";
$db['example']['database'] = "example";
$db['example']['dbdriver'] = "mysql";
$db['example']['dbprefix'] = "";
$db['example']['active_r'] = TRUE;
$db['example']['pconnect'] = TRUE;
$db['example']['db_debug'] = TRUE;
$db['example']['cache_on'] = FALSE;
$db['example']['cachedir'] = "";
$db['example']['char_set'] = "utf8";
$db['example']['dbcollat'] = "utf8_general_ci";

// Example 2
$db['example2']['hostname'] = "localhost";
$db['example2']['username'] = "root";
$db['example2']['password'] = "root";
$db['example2']['database'] = "testfoo";
$db['example2']['dbdriver'] = "mysql";
$db['example2']['dbprefix'] = "";
$db['example2']['active_r'] = TRUE;
$db['example2']['pconnect'] = TRUE;
$db['example2']['db_debug'] = TRUE;
$db['example2']['cache_on'] = FALSE;
$db['example2']['cachedir'] = "";
$db['example2']['char_set'] = "utf8";
$db['example2']['dbcollat'] = "utf8_general_ci";

// Check the configuration group in use exists, if not use the default
$active_group = (defined('SITE') && array_key_exists(SITE, $db)) ? SITE : 'default';

?>

The little snippet of code at the bottom will check to see if the SITE constant you have set matches up with a database group. If it doesn’t, it will use the default configuration group.

Your CodeIgniter set-up should now work with any domain you happen to point to it. You even run simple little

 if(SITE == 'example2')

checks anywhere within your code to do special code for a certian site, although I would not reccomend you doing this too heavily.

I’ve compiled a nice, long list of CodeIgniter’s hidden secrets full of little helpful snippets, concealed functions and long-unused classes to help you get the most out of the framework.

The Database Forge

CodeIgniter’s database class goes much further than the simple ActiveRecord system. It’s an extremely powerful tool, and includes the database forge class. This is rarely used – many seem to skip over this documentation section and onto the more promising ActiveRecord class, but this can be really helpful – especially if you need to create, edit and delete actual databases.

You can load the database forge class using a variant of the standard CodeIgniter loading convention.

$this->load->dbforge();

And then call options on it by using the “dbforge” variable.

//Create a database called 'users'
$this->dbforge->create_database('users');

You can find out more about the database forge class at the user guide page, found here.

auto_typography();

One of the most useful functions, and yet often unheard of inside CodeIgniter is auto_typography(), residing in the seldom used typography helper. This helpful function converts double-line breaks to paragraphs, single line breaks to
tags, quote tags to typographically correct curly quotes and apostrophes, double dashes to em dashes and a few other things to make your text semantically and typographically correct.

It’s usage is simple:

//Load the typography helper
$this->load->helper('typography');

//Convert some text
$converted_text = auto_typography($original_text);

It takes two parameters, the string to convert and a boolean value stating if to shorten more than two line breaks down to two. This defaults to FALSE. This is a great function, but can be pretty processor intensive, especially when you are parsing large quantities of text, so it’s a good idea to cache your pages.

CodeIgniter Page Caching

Which brings me perfectly onto my next point, page caching! A post made last year by one of my CodeIgniter all-star brethren (term coined by Michael Wales, circa 2008.), Elliot Haughin benchmarks different caching mechanisms and proves that CodeIgniter’s basic caching solution deserves much more credit then it gets.

CodeIgniter’s caching solution is primitive at heart, but works extremely well and is very easy to set up and use. It’s often unused because people go for other alternatives such as Memcache or APC, both great caching systems, but CodeIgniter’s is fine when all you need is simple page caching.

The caching system is built into the output class, which is automatically instantiated by the system, so you don’t need to load it. There is only one function required to set the cache – and the system handles the rest. You can place it anywhere in the controller function you want to cache – the order is irrelevant. You simply pass the function the number of minutes you want to cache the function for.

$this->output->cache(60); // 60 mins = 1 hour

Combine CodeIgniter’s solution with a caching system such as Memcache, APC or EAccelerator, and you can greatly improve your web application’s speed. Read more about CodeIgniter’s caching system, yet again on the user guide.

url_title();

Favourite of blogging engines CodeIgniter-wide, url_title(), a wee function hiding in the depths of the URL helper takes a string and converts it into a URL friendly string. This is commonly used when creating a slug for a page – it will turn the string “CodeIgniter is Awesome” into “codeigniter-is-awesome”, “Woo! Mama! Hot-diggedy Damn!” into “woo-mama-hot-diggedy-damn” and so forth.

send_email(); & CodeIgniter’s Email Class

If you want to send an email, using basic settings via PHP’s mail() function, you can use this sweet little function. Simply pass it the recipient, the subject and the message and it will send the email. This is great if you want to send a quick log message for instance, but if you need more flexibility and power you should check out the Email library.

I looked into a few options and decided on Mosso to be my cloud server providers. This comes down to many reason: they are cheap, they are a Rackspace company so they are running very reliable hardware and they recently absorbed Slicehost, so you know their control panels are good.

With my hosting providers found, I had to pick my software. I decided to use Virtualmin as there is a free alternative that does basically everything you need from a VPS GUI and saves me the cost of paying for cPanel/WHM.

This decision restricted my choice of Operating System a little, as sadly the newest version of Ubuntu that Virtualmin supports is 8.04 LTS. Thats good enough for me, and LTS means more applications will worry about supporting it.

Anyhow, enough of that. Time to see my slightly drunken screencast in action.

Part 1

Part 2

To access your CodeIgniter helpers from Smarty, all you need to do is make a new file in your “plugins/” directory called “helper.modifier.php” and paste in the following code:

<?php
/*
* Smarty plugin
* -------------------------------------------------------------
* File:     modifier.helper.php
* Type:     modifier
* Name:     helper
* Purpose:  Call CodeIgniter helpers from within Smarty.
* -------------------------------------------------------------
*/
function smarty_modifier_helper($string, $helper_file, $helper_func)
{
if (!function_exists("get_instance")) {
return "Can't get CI instance";
}

if (!function_exists($helper_func)) {
$CI =& get_instance();
$CI->load->helper($helper_file);
}

// Get all the params passed in as there might be a few
$params = func_get_args();

// String provided should be the first param and we dont want helper file or helper func being passed
$params[0] = $string;
unset($params[1]);

// Call the function with the params provided
return call_user_func_array($helper_func, array_values($params));
}
?>

Save that and try it out in one of your Smarty controlled view files. For example:

<p>Check out this amazing item</p> {$item.url|helper:'url':'anchor':$item.title:'class="more params"'}

With Smarty modifiers, the item you are modifying is the first param. The modifier is called after a pipe character “|” and then more parameters are separated by “:”. With this specific modifier, you list the helper, then the helper function, then as many params afterwards as you like.