Here is a small code snippet that will give you intersecting dates between 2 date ranges. Say, for example, you have 2 date ranges, 1-Jan-2011 to 31-Mar-2011 and 23-Feb-2011 to 4-May-2011.  This function will give you 23-Feb-2011 to 31-Mar-2011 as result.

Here is the code:

$a1  = "2011-01-01";
$a2  = "2011-03-31";
$b1  = "2011-02-23";
$b2  = "2011-05-04";

$intersection = getIntersection($a1,$a2,$b1,$b2);
if($intersection === false)
{
	echo 'No intersecting dates found';
}
else
{
	echo 'From '.date('d-M-Y', $intersection['start']).' till '.date('d-M-Y', $intersection['end']);
}

function getIntersection($a1,$a2,$b1,$b2)
{
	$a1 = strtotime($a1);
	$a2 = strtotime($a2);
	$b1 = strtotime($b1);
	$b2 = strtotime($b2);
	if($b1 > $a2 || $a1 > $b2 || $a2 < $a1 || $b2 < $b1)
	{
		return false;
	}
	$start = $a1 < $b1 ? $b1 : $a1;
	$end = $a2 < $b2 ? $a2 : $b2;

	return array('start' => $start, 'end' => $end);
}

Above will show the following on browser :

From 23-Feb-2011 till 31-Mar-2011

If the 2 date ranges have any intersecting dates, an array will be returned which will have start and end elements that represent the beginning and end of intersecting range.  Set of dates given below will return false as there are no intersecting dates.

$a1  = "2011-01-01";
$a2  = "2011-03-31";
$b1  = "2011-04-23";
$b2  = "2011-05-04";

$intersection = getIntersection($a1,$a2,$b1,$b2);

This will show

No intersecting dates found

The code is self-explanatory. As you can see, first we have used php function strtotime to convert all dates to timestamps. Then we can compare them easily. This way you can use whatever(allowed) date format you wish.

I have combined the 2 previous posts for expanding and shortening goo.gl URLs and have created a small class for it. Below is the download link for the class.

Expanding a URL

<?php
include('GAPIClass.php');

$objAPI = new GAPIClass('your_api_key_here');
$result = $objAPI->expand('http://goo.gl/WlFX');
if(FALSE === $result)
{
	echo $objAPI->error;
}
else
{
	echo 'Long URL:'.$result;
}
?>

Shorten A URL

<?php
include('GAPIClass.php');

$objAPI = new GAPIClass('your_api_key_here');
$result = $objAPI->shorten('https://www.packtpub.com/php-jquery-cookbook-to-create-interactive-web-applications/book');

if(FALSE === $result)
{
	echo $objAPI->error;
}
else
{
	echo 'Short URL:'.$result;
}
?>

As I have mentioned earlier that Google recommends an API key. The class has a flag variable called keyWarning. By default it is true and it will show the following warning message if you do not pass an API key while instantiating the class:

Currently you are not using an API key. It is recommended that you use one. Click here to learn more about the API key

To turn this notification off, just use this line:

$objAPI->keyWarning = false;

If you are getting an internal server error 500 after installing wordpress while accessing admin, here is the fix.

Most likely it is caused by low memory limit on your server. To fix it, create a new file named php.ini in you wp-admin directory and put the following line in it.

memory_limit = 64M

Save the file, then reload the admin page and it will work fine.

In past 2 posts you saw how short URLs can be expanded using the Google URL shortener API. This post shows how URLs can be shortened using this API.

API key is not mandatory for test purpose. Use this link to get an API key.

For shortening URLs, 2 points must be noted. First, a HTTP POST is required and the post data should be in JSON format. Here is the code:

//This is the URL you want to shorten
$longUrl = 'https://www.packtpub.com/php-jquery-cookbook-to-create-interactive-web-applications/book';
$apiKey = 'your_api_key_here';
//Get API key from : http://code.google.com/apis/console/

$postData = array('longUrl' => $longUrl, 'key' => $apiKey);
$jsonData = json_encode($postData);

$curlObj = curl_init();

curl_setopt($curlObj, CURLOPT_URL, 'https://www.googleapis.com/urlshortener/v1/url');
curl_setopt($curlObj, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curlObj, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($curlObj, CURLOPT_HEADER, 0);
curl_setopt($curlObj, CURLOPT_HTTPHEADER, array('Content-type:application/json'));
curl_setopt($curlObj, CURLOPT_POST, 1);
curl_setopt($curlObj, CURLOPT_POSTFIELDS, $jsonData);

$response = curl_exec($curlObj);

//change the response json string to object
$json = json_decode($response);

curl_close($curlObj);

echo 'Shortened URL is: '.$json->id;

Here is the JSON response from Google:

{
 "kind": "urlshortener#url",
 "id": "http://goo.gl/lBfOH",
 "longUrl": "https://www.packtpub.com/php-jquery-cookbook-to-create-interactive-web-applications/book"
}

You can also read these:

• PHP class for expanding and shortening URLs using Google URL shortener API
• Expanding URLs using cURL
• Expand URLs using file_get_contents

Yesterday I wrote this post explaining how short goo.gl URLs can be expanded using the newly launched goo.gl API. In that code we used php function get_file_contents to get the response from API.

How about implementing the same functionality using cURL now? If you have libcurl support installed with PHP, you are ready to use the cURL functions of PHP.

Here is the code. API key is not mandatory but Google recommends that you use one. It will increase your per day usage limits too. Follow this link to get an API key.

$shortUrl = 'http://goo.gl/WlFX';
$apiKey = 'your_api_key_here';

$curlObj = curl_init();

curl_setopt($curlObj, CURLOPT_URL, 'https://www.googleapis.com/urlshortener/v1/url?shortUrl='.$shortUrl.'&key='.$apiKey);
curl_setopt($curlObj, CURLOPT_HEADER, 0);
curl_setopt($curlObj, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curlObj, CURLOPT_SSL_VERIFYPEER, 0);

$response = curl_exec($curlObj);

curl_close($curlObj);
$json = json_decode($response);

if($json->status === "OK")
{
	echo $json->longUrl;
}
else
{
	echo 'Bad luck.';
}

And here is the full JSON response:

{
 "kind": "urlshortener#url",
 "id": "http://goo.gl/WlFX",
 "longUrl": "https://www.packtpub.com/php-jquery-cookbook-to-create-interactive-web-applications/book",
 "status": "OK"
}

Am important point to note. Since the API is on https, set the value for CURLOPT_SSL_VERIFYPEER to false. This will stop cURL from verifying the SSL certificate.

Yesterday. google launched an API for its URL shortening service http://goo.gl. Using this API developers will be able to expand/shorten URLs and get a user’s analytics and history programmaticaly.

Below is a small snippet of PHP code that expands a short URL. The response comes in JSON format, so we will use the json_decode function to convert it to object.

$shortUrl = 'http://goo.gl/WlFX';
$response = file_get_contents('https://www.googleapis.com/urlshortener/v1/url?shortUrl='.$shortUrl);
$json = json_decode($response);

if($json->status === "OK")
{
	echo $json->longUrl;
}
else
{
	echo 'Bad luck.';
}

Here is the full successfull response in JSON format.

{
 "kind": "urlshortener#url",
 "id": "http://goo.gl/WlFX",
 "longUrl": "https://www.packtpub.com/php-jquery-cookbook-to-create-interactive-web-applications/book",
 "status": "OK"
}

Finally, note that Google recommends the use of an API key. You can visit this link to read more about key and get a key from this link.

After using the key, your URL will look like the following:

$shortUrl = 'http://goo.gl/WlFX';
$apiKey = 'your_key_here';
$response = file_get_contents('https://www.googleapis.com/urlshortener/v1/url?shortUrl='.$shortUrl.'&key='.$apiKey);

Every web application requires configuration files which contain values that are used throughout the application. In this post we will look at some of the methods developers use to define configuration settings and also what should be avoided.

The ugly way

I have seen many many developers do this and am myself guilty of doing it during my initial coding days. Consider the following code.

//development
	define("HOST", "localhost");
	define("DATABASE_USER", "root");
	define("DATABASE_PASSWORD", "something");
	define("DATABASE_NAME", "UJNEEA");
	define('FILE_UPLOAD_PATH', 'C:/wamp/www/project/uploads/');

/*
	//production
	define("HOST", "localhost");
	define("DATABASE_USER", "username");
	define("DATABASE_PASSWORD", "password");
	define("DATABASE_NAME", "liveDB");
	define('FILE_UPLOAD_PATH', '/home/project/public_html/uploads/');
*/

Developers define 2 sets of same variables for each environment. First set is for development environment while second is for production. To switch the configuration developer must comment all other sets and uncomment the desired one. This is untidy and error prone. Never ever use this in your applications.

Using a flag

Above method can be significantly improved by using a variable as a flag. The example is given below.

define ('DEVELOPMENT', true);

if(DEVELOPMENT)
{
	define("HOST", "localhost");
	define("DATABASE_USER", "root");
	define("DATABASE_PASSWORD", "something");
	define("DATABASE_NAME", "myDB");
	define('FILE_UPLOAD_PATH', 'C:/wamp/www/project/uploads/');
}
else
{
	define("HOST", "localhost");
	define("DATABASE_USER", "username");
	define("DATABASE_PASSWORD", "password");
	define("DATABASE_NAME", "liveDB");
	define('FILE_UPLOAD_PATH', '/home/project/public_html/uploads/');
}

Define a variable which will tell whether it is a development environment or a production one. Now when you have to switch environments, you do not have to do that comment/uncomment stuff. Just set the flag to true or false and PHP will pick the values accordingly.

Using multi-dimensional arrays

If you have used CodeIgniter, you must be familiar with this concept. Just use multi-dimensional arrays. Here is the explanation from CodeIgniter documentation itself.

“The reason we use a multi-dimensional array rather than a more simple one is to permit you to optionally store multiple sets of connection values. If, for example, you run multiple environments (development, production, test, etc.) under a single installation, you can set up a connection group for each, then switch between groups as needed.”

$active_group = "test";

$db['default']['hostname'] = "localhost";
$db['default']['username'] = "root";
$db['default']['password'] = "pass";
$db['default']['database'] = "someDB";
$db['default']['file_upload_path'] = "C:/wamp/www/project/uploads/'";

$db['test']['hostname'] = "otherHost";
$db['test']['username'] = "root";
$db['test']['password'] = "password";
$db['test']['database'] = "hci";
$db['test']['file_upload_path'] = "C:/wamp/www/project/uploads/'";

$db['staging']['hostname'] = "evenAnotherHost";
$db['staging']['username'] = "root";
$db['staging']['password'] = "password";
$db['staging']['database'] = "dbname";
$db['staging']['file_upload_path'] = "E:/public_html/project/uploads/'";

In this method, you only have to set the value of variable $active_group to whatever environment you wish to point to. This is much cleaner and configuration for more then 2 environments can be defined.

Other methods

There are many more ways you can define your configuration files. Some of them include:

• ini files
• XML
• YAML

I will explain parsing the ini file using parse_ini_file function in an upcoming article.

Thanks for reading.

Here is one more sample chapter from my book. It explains reading, writing and editing XML files with PHP and jQuery. Below are the chapter contents.

• Loading XML from files and strings using SimpleXML
• Accessing elements and attributes using SimpleXML
• Searching elements using XPath
• Reading an XML using DOM extension
• Creating an XML using DOM extension
• Modifying an XML using DOM extension
• Parsing XML with jQuery

To read the full chapter follow this link - https://www.packtpub.com/article/working-with-xml-documents

You can also read the chapter on using JSON with PHP and jQuery.

I mentioned in a previous post that I was writing a book on PHP and jQuery. Well, after a labor of around 7 months the book is out now. It is available on Packt website as well as Amazon.

Meanwhile, to help you make a decision, a sample chapter from the book is available on Packt website. The chapter is Working with JSON in PHP and jQuery and it contains 4 articles that explain creating, reading and writing JSON in PHP as well as jQuery.

Below are the topics that this chapter covers:

• Creating JSON in PHP
• Reading JSON in PHP
• Catching JSON parsing errors
• Accessing data from a JSON in jQuery

To read the full chapter, just follow this link http://www.packtpub.com/article/working-json-php-jquery

Yes that’s right and it is called PHP jQuery Cookbook.  As the name suggests, it’s about creating rich internet applications using 2 of my favorite technologies – PHP and jQuery.

I love coding web apps and helping others find solutions. Perhaps that is the reason I agreed to write when the wonderful people at Packt Publishing contacted me. (Also, a book on resume isn’t that bad either )

Another reason is I love Open source. It is a lovely philosophy and I am a strong believer in it. Having learnt so much from the Open source community since I started coding, I have always wanted to return something back. Nothing could have been better then this. And did I mention, Packt pays direct royalty to a project if they sell a book written on the same.

Long story short, the book is cookbook with around 65 recipes covering PHP, jQuery, MySql and some API’s (Flickr, Youtube).

Structure wise, it has 10 chapters in all.

• Handling Events
• Combining PHP and jQuery
• Working with XML documents
• Working with JSON
• Working with Forms
• Adding Visual effects to forms
• Creating cool Navigation Menus
• Data binding with PHP and jQuery
• Enhancing your site with PHP and jQuery
• Appendix – FireBug

The book is available now will be available by 14th December Christmas this year or January next year. You can have a look in detail about what it is all about on Packt Website. Order a copy in case you find it interesting