Wayne May

Adding a hook to the PHP output headers

Wayne May — Mon, 05 Mar 2012 12:13:57 PST

With PHP 5.4 you can now easily add a callback function, using header_register_callback, to be called just before the headers are sent to the browser.

For example:

  header('Content-Type: text/plain');
  header('X-Test: test-header');
 
  header_register_callback( 'remove_XPoweredBy_header' );
 
  echo 'Testing';

This allows you to set a callback function, in this case, remove_XPoweredBy_header.

An example of something to do in this callback function:

  function remove_XPoweredBy_header()
  {
    header_remove('X-Test');
  }

This will prevent “X-Test” from showing up in the headers.

Getting and Setting HTTP Response codes in PHP 5.4

Wayne May — Mon, 05 Mar 2012 11:56:56 PST

A new function were added to PHP 5.4 that make getting and setting HTTP response code easy.

To get the current HTTP code, all you have to do is call the http_response_code function

1	echo http_response_code() //If all is ok, this should echo 200

To set the HTTP response code, add a parameter to the http_response_code function

1 2	http_response_code(404) echo http_response_code() //This should echo 404 and return 404 in the header

Class Member Access on Instantiation with PHP 5.4

Wayne May — Mon, 05 Mar 2012 11:00:59 PST

Class members can now be accessed on instantiation in PHP 5.4. This is a very handy addition.
Before PHP 5.4 you had to create an object into a variable, and then access the class member/function:

1
2
3

  //The old way
  $object = new SomeClass();
  $object->someFunction();

With PHP 5.4 you can access the class member directly on instantiation:

1 2	//The new way (new SomeClass)->someFunction();

Function Array Dereferencing in PHP 5.4

Wayne May — Mon, 05 Mar 2012 10:30:09 PST

PHP now supports array dereferencing directly from a function call. Before PHP 5.4 you had to store the returning value from a function into a variable, and then use the variable.
Eg:

1 2	$cars = $explode(",", "ferrari,lamborghini,maserati,bugatti"); echo $cars[3]; //bugatti

Now with PHP 5.4 you can do it like this:

1	echo $explode(",", "ferrari,lamborghini,maserati,bugatti")[3]; //bugatti

Another example with your own function:

  function get_cars()
  {
    return ["ferrari","lamborghini","maserati","bugatti"];
  }
  echo get_cars()[3];  //bugatti

The Shorter Array Syntax in PHP 5.4

Wayne May — Mon, 05 Mar 2012 10:00:28 PST

PHP 5.4 introduced a new shorter array syntax, similar to the syntax used in JavaScript.

The old, longer syntax:

1 2	//The old way $cars = array("ferrari", "lamborghini", "maserati", "bugatti");

The new syntax is an alternative to the old syntax.

1 2	//The short way $cars = ["ferrari", "lamborghini", "maserati", "bugatti"];

Check if PHP is using HTTPS (SSL)

Wayne May — Fri, 09 Dec 2011 13:00:03 PST

I had to come up with a way to check if PHP is running in SSL mode today. This will work on both Apache, Nginx and IIS

function is_ssl()
{
    $secure_connection = false;
 
    if (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off'
        || $_SERVER['SERVER_PORT'] == 443) 
    {
        $secure_connection = true;
    }
 
    return $secure_connection;
}

I found this little nifty function on StackOverflow

Detecting a Multi-Dimensional Array in PHP

Wayne May — Fri, 09 Dec 2011 08:00:21 PST

I recently had to find a quick way to check if an array is a multi-dimensional array, only to find that there are no PHP built-in function to do this. Here is a quick and easy way to do it:

function is_multi_array( array $arr )
{
    return is_array($arr[key($arr)]);
}

This can easily be used in the following context:

$a = array("dimension1" => array("dimension2" => "I like it") );
if( is_multi_array( $a ) )
{
    echo $a['dimension1']['dimension2'];
}

Making a Radio Group Tab-able Using jQuery

Wayne May — Thu, 08 Dec 2011 13:00:08 PST

Recently I had to come up with a solution to make radio boxes tab-able. Mozilla Firefox allows you to tab over each radio box in a group, however, all other browsers do not. The solution is actually quite simple. First, in your HTML make sure to name your radio boxes with the same name, but also add a .1, .2, .3, and so on, to separate them. You will also need a hidden element. This is the one you want to do validation against. For example:

    <input type="hidden" name="group1" value="" />
    <input type="radio" name="group1.1" value="1" tabindex="10" /> Radio 1
    <input type="radio" name="group1.2" value="2" tabindex="11" /> Radio 2
    <input type="radio" name="group1.3" value="3" tabindex="12" /> Radio 3

Now add a little bit of code that will parse once the DOM is ready:

    <script type="text/javascript">
        $(document).ready( function() {
            rt = new RadioTabs();
            rt.init( "group1", ["group1.1", "group1.2", "group1.3"], ["click"] );
        });
    script>

All this does is tell the RadioTabs class (coming next) which tabs will be in the group. Finally, add this somewhere on you page. Preferably on a separate page.

	/* Create Tabable Radio Boxes */
	function RadioTabs() {
		/* Declare Private Members and Methods */
		var hidden = '';
		var group = [];
		var events = [];
 
		/* void Bind Events to each individual Radio Box */
		var bindEvents = function () {
			//Loop through Events
			for( var e = 0; e < events.length; e++ ) {
				//Loop through Radio Buttons
				for( var g = 0; g < group.length; g++ ) {
					//Add a Rel value to each group box - to be used in the bind
					$('input:radio[name="' + group[g] + '"]').attr('rel', g);
					//Bind actual events to each radio box
					$('input:radio[name="' + group[g] + '"]').bind(events[e], function( event ) {
						var n = $(this).attr('rel');
						$('[name="' + hidden + '"]').val( $('[name=' + group[n] + ']').val() );
						//Step through radio group and set to false
						for( var i = 0; i < group.length; i++ ) {
							if( group[i] != group[n] ) {
								$('input:radio[name="' + group[i] + '"]:checked').attr( 'checked', false );
							}
						};
					});
				}
			}
		};
 
		/* Declare Public Members and Methods */
		return {
			/* string Set the Hidden Input Element */
			setHidden    : function ( value ) {
				hidden = value;
			},
			/* array Set the Radio Group Elements */
			setGroup    : function ( values ) {
				group = values;
			},
			/* array Set the Events to bind to */
			setEvents    : function ( values ) {
				events = values;
			},
			/* void Init the script */
			init            : function ( hid, grp, evt ) {
				this.setHidden( hid );
				this.setGroup( grp );
				this.setEvents( evt );
				bindEvents();
			}
		};
	};

All the above piece of code does is it will allow you to tab through the radio boxes, and then set the hidden elements value to that of the selected radio box. You might have to tweak a little bit with CSS in IE7 and 8 (I don’t support 6 anymore) to make it show that the box is selected. This should do the trick

    input[type=radio]:focus {
        outline:#000 dotted thin;
    }

PHP Safe Redirect Function

Wayne May — Thu, 08 Dec 2011 08:00:02 PST

I see PHP code every day making use of the header function. Its the standard way to make redirects in PHP, but will fail if ANY output was sent to the browser before its called. There is a safer way to do this, which use JavaScript and meta redirects as a fail safe:

    /**
     * Do a Safe Redirect
     *
     * This function will first try to do a server-side redirect, if it is not possible, if will fall back to a
     * Javascript redirect, if that fails, it will try a HTML redirect.
     * @param $url
     */
    function safe_redirect($url, $method = 'PHP')
    {
        try
        {
            if (!headers_sent())
            {
                //If headers are not sent yet... then do a php redirect
                @header('Location: '.$url);
                exit;
            } else throw new Exception();
        }
        catch( Exception $ex )
        {
            //If headers are sent... do a JavaScript redirect...
            //if javascript disabled, do html redirect.
            echo '';
            echo '';
            exit;
        }
    }

Basically, this will check to see if headers were sent, if not, it will allow for a PHP header redirect, If output were set, it will make use of JavaScript, and, as a backup if JavaScript is not installed, it will cause a meta redirect.

PHP use Backticks as Execution Operators

Wayne May — Wed, 07 Dec 2011 13:00:50 PST

PHP use backticks as execution operators, which will return the output of to be assigned to a variable. Any code between backticks will be executed as a shell command – the backtick operator is identical to shell_exec()

One example where I found this useful was to get the fully qualified domain name of a server. I could do something like:

1	$fqdn = shell_exec('hostname --fqdn');

or using backticks, I can so something like:

1	$fqdn = `hostname --fqdn`;

Notice that I am using backticks (`) and not single quotes (‘)