Simple and fast solution for turn the website off; use the Plugin WP Maintenance Mode, original for the activation of the maintenance mode; but its easy for this requirement. As useful; the plugin send an 503 Service Unavailable header.

Set the following settings in the plugin

Code for the field text, the video markup:

<iframe src="http://player.vimeo.com/video/31100268?byline=0&portrait=0" width="400" height="225" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>
<p><a href="http://vimeo.com/31100268">PROTECT IP / SOPA Breaks The Internet</a> from <a href="http://vimeo.com/fightforthefuture">Fight for the Future</a>.</p>

Here is the result for not signed in visitors:

All these solutions have their limitations, are inflexible and you go into a dependency that will be hard to get out and with each update of WordPress you have to check if the Plugin is still working or has any bugs with the new version. Therefore, I would suggest a solution that we use in our Inpsyde Team frequently for customers and maintained their strength in the flexibility, in extensibility and in its capacity to use the WordPress standard without changing the core or anything else. You can deactivate the Plugin at any time, you won't lose anything, your website remains the same.

Why multilanuage?

• 2/3, if not even more, of the worldwide population speak another language
• Globale Aufstellung von Unternehmen
• Better distribution of content
• Service for the client
• Search Engine Optimization

The solution

WordPress Multi-site provides the solution already.
This makes the management of different instances, with similarities and differences, with the help of an installation possible. The exchange of data is possible via core functions, which get united and simplified via Plugin.

Advantages

• WordPress Core Functions
• No dependency to Plugins
• Independent to WordPress development*
• Control Themes, Plugins at a central place, use them decentralized
• Low maintenance
• Seperating languages in Backend/Frontend (user dependent)
• Complete mirrored or in every content form seperated
• Subdomains or Subdirectories
• de.example.com, example.com/de
• Seperate Domains via Domainmapping
• example.de, example.com
• Free in development in design and usability
• Optimization not only on frontend, also lang-attributes, SEO

Plugin

With all these requirements and benefits, we use a base that is available as a Plugin in the official repository of WordPress: Multilingual Press . The plugin provides several convenient tools to use Multisite for the implementation of multilingualism.

This plugin simplifies the identification of different blogs in the network to a language and linking to other blogs, so that when you publish the content in blog A, it will create a post as draft in blog B. Thus, the articles are in relation, the system knows this and with the help of some functions, it may be used in the frontend and backend.
The Plugin provides in the article or page the ability to see a meta box with the content of the linked data, in the simplest case as a translation aid. Similarly, there is a widget that simplifies the frontend to change. In each blog you can be make ​​some adjustments, assigning a flag and language.

An outlook

We are in the midst of the development, which adds the extra help. For example a dashboard widget with the overview of article and all links, an extension of the mediathek to seperate global content across all blogs and independent content per blog. Similarly, there are helpers for updating existing installations. In addition there is the possibility to directly load the language in the backend, without the need of FTP/SSH and assign the languages accordingly​​. We will also add the function to copy existing blogs with all the content and options if you want to.

Summary

WordPress Multisite provides the basis and with some adjustments, a clean, controlled solution exists for the use of WordPress in a multilingual environment. Now it's up to you - use Multisite, Test the Plugin and give us a feedback, preferable on our repo on Github.

.

This was our last door of our Advent Calendar. We hope you enjoyed it!

We wish you a Merry Christmas and thanks a lot for reading our posts!

Why WordPress doesn't follow MVC pattern consistently?

If we have a close look on WordPress, we can detect an MVC pattern. By separating the Themes (view) from the core (model) it gives the impression WordPress pursues an MVC pattern. But this patternn is found only in the frontend. Let's take a closer look and we see that there is no such logic for the admin area. So, the view for the admin area has to be anchored somewhere in the core. We can also notice that in the core itself are lose SQL queries within PHP. Well, a general separation of view and logic is not equal MVC. An MVC-Pattern is principally composed of a sort of object-oriented programming paradigm, in WordPress, these can also be found occasionally, but we find much more procedural than object-oriented programming paradigms. Conclusion WordPress itself does not pursue a MVC pattern, but it is quite possible MVC principles, as we used in the following.

function get_some_foo() {
	$my_foo = 'This is Foo!';
	return $my_foo;
}

function some_foo() {
	$foo = get_some_foo();
	echo $foo;
}

Why is this useful? We want the function some_foo() returns a predefined output. In another template we want to change the default behavior of the function some_foo(). In order to effectively reflect both requirements, two functions are defined. The first function consists only the elementary logic and is only returned as return values​​, it is always preceded by a get_.... The second function includes predefined information, which in turn can be HTML, test logic, loops, or a hook.

function get_some_foo() {
	$foo_bar_array = array( 'Foo', 'Bar', 'FooBar', 'BarFoo' );
	$foo_bar_array = apply_filters( 'some_foo_array', $foo_bar_array );

	return $foo_bar_array ;
}

function some_foo() {
    $foo_list = '<ul>'; 

    foreach( get_some_foo() as $foo_key => $foo_value ){
		$foo_list .= '<li>' . $foo_value . '</li>';
    }

    $foo_list .= '</ul>';

    echo apply_filters( 'some_foo', $foo_list );
}

In the previous example in each of the two functions with the function apply_filters() the possibility will be created, to change returned values later as you desired. A manipulation can take place via the so-defined hooks some_foo_array or some_foo. Here is an example of how a possible manipulation can look with the two defined hooks.

In the next code example, we change an array $foo_bar_array and the HTML output. This involves the two hooks some_foo_array and some_foo, which were set with apply_filters('some_foo' .... With the function add_filter() filter functions for further processing in the global variable $wp_filter will be registered.

function get_my_some_foo( $foo_bar_array ) {
	$foo_bar_array[ count( $foo_bar_array ) + 1 ] = 'FuuBoo';

	return $foo_bar_array ;
}

function my_some_foo( $foo_list ) {
    $foo_list = str_replace( 'ul', 'ol', $foo_list ); 

    return $foo_list;
}

add_filter( 'some_foo_array', 'get_my_some_foo');
add_filter( 'some_foo', 'my_some_foo');

// do not forget, call some_foo()
some_foo();

Let's look briefly what's happening. What outputs some_foo() has without manipulation we see in the following example.

function get_some_foo() {
	$foo_bar_array = array( 'Foo', 'Bar', 'FooBar', 'BarFoo' );
	$foo_bar_array = apply_filters( 'some_foo_array', $foo_bar_array );

	return $foo_bar_array ;
}

function some_foo() {
    $foo_list = '<ul>'; 

    foreach(get_some_foo() as $foo_key => $foo_value){
		$foo_list .= '<li>' . $foo_value . '</li>';
    }

    $foo_list .= '</ul>';

    echo apply_filters( 'some_foo', $foo_list );
}
?> 

// output
<ul>
	<li>Foo</li>
	<li>Bar</li>
	<li>FooBar</li>
	<li>BarFoo</li>
</ul>

In the next example we use the functions defined in the hooks some_foo_array and some_foo to add the array another element to make the unordered list, an ordered list.

function get_my_some_foo( $foo_bar_array ) {
	$foo_bar_array[ count( $foo_bar_array ) + 1 ] = 'FuuBoo';

	return $foo_bar_array ;
}

function my_some_foo( $foo_list ) {
    $foo_list = str_replace( 'ul', 'ol', $foo_list ); 

    return $foo_list;
}

// register Hooks in the stack ($wp_filter)
add_filter( 'some_foo_array', 'get_my_some_foo');
add_filter( 'some_foo', 'my_some_foo');
?>

//output
<ol>
	<li>Foo</li>
	<li>Bar</li>
	<li>FooBar</li>
	<li>BarFoo</li>
	<li>FuuBoo</li>
</ol>

How does add_filter and apply_filters work in the program flow?
Each hook which should be executed is registered with add_filter or add_action in the global variable $wp_filter. If the function apply_filters() is called, an appropriate filter function based on the transmitted variables will be searched in the $wp_filter, if this is registered with add_filter, the appropriate function will execute. Now values will be manipulated now and then passed back to apply_filters.

Let's take our example from above, it looks like this.

<?php
// the default function
function get_some_foo() {
	$foo_bar_array = array( 'Foo', 'Bar', 'FooBar', 'BarFoo' );
	$foo_bar_array = apply_filters( 'some_foo_array', $foo_bar_array );

	return $foo_bar_array ;
}

// the filter function
function get_my_some_foo( $foo_bar_array ) {
	$foo_bar_array[ count( $foo_bar_array ) + 1 ] = 'FuuBoo';

	return $foo_bar_array ;
}

// register function in $wp_filter
add_filter( 'some_foo_array', 'get_my_some_foo' );
?>

Without hook functionality the whole thing would look like the following. Although we have much less code, but this is not reusable.

<?php
//Das ist unsere default Funktion
function get_some_foo() {
	$foo_bar_array = array( 'Foo', 'Bar', 'FooBar', 'BarFoo' );
	$foo_bar_array[ count( $foo_bar_array ) + 1 ] = 'FuuBoo';

	return $foo_bar_array ;
}
?>

The function to store the entries is fb_save_custom_user_profile_fields() and here it is important to check the rights of each active user, only if the rights are available, in this case for editing users (edit_user), then data may be stored.
The actual saving of data takes place via update_usermeta().

It can pass all kinds of fields of course, the input field is just an example. It is advisable to outsource the functions in a Plugin, an alternative is also the functions.php of the Theme, but is certainly not the best way.

Each function of the small sample was referred to two hooks. Because WordPress differentiate between editing of user profiles and update personal data. This is done using the constant IS_PROFILE_PAGE. On default this constant is on TRUE and so would the hooks show_user_profile and personal_options_update be enough to bring in new fields and save them. But this can vary depending on the installation and this way the admin cannot maintain these new fields. In particular, two more hooks are needed. Otherwise there might be many cases, where the admin has to maintain data which the user doesn't even see in his profile.

function fb_add_custom_user_profile_fields( $user ) {
?>
	<h3><?php _e('Extra Profile Information', 'your_textdomain'); ?></h3>

	<table class="form-table">
		<tr>
			<th>
				<label for="address"><?php _e('Address', 'your_textdomain'); ?>
			</label></th>
			<td>
				<input type="text" name="address" id="address" value="<?php echo esc_attr( get_the_author_meta( 'address', $user->ID ) ); ?>" class="regular-text" /><br />
				<span class="description"><?php _e('Please enter your address.', 'your_textdomain'); ?></span>
			</td>
		</tr>
	</table>
<?php }

function fb_save_custom_user_profile_fields( $user_id ) {

	if ( !current_user_can( 'edit_user', $user_id ) )
		return FALSE;

	update_usermeta( $user_id, 'address', $_POST['address'] );
}

add_action( 'show_user_profile', 'fb_add_custom_user_profile_fields' );
add_action( 'edit_user_profile', 'fb_add_custom_user_profile_fields' );

add_action( 'personal_options_update', 'fb_save_custom_user_profile_fields' );
add_action( 'edit_user_profile_update', 'fb_save_custom_user_profile_fields' );

Much is the same, but not all, and in this small article I would like to briefly explain how you set settings in the database when you activate a Plugin.

The best case for this is a Function of WordPress, which is triggered when activating a plugin register_activation_hook(). This Function will be called in init or constructor of the Plugin. In the called Function are the functions to store the settings of WordPress in the table options - add_option(). In Multisite there is also a function for it - add_site_option().

Now you have to separate, if the Plugin is activated within the Network, in the management of Multisite installation, or if it is only used in one of the blogs in the network or a single installation. There are currently no functions, but a value that is passed. The following example illustrates it:

register_activation_hook( __FILE__, 'fb_add_config' );
function fb_add_config() {

	$data = array(
		'active' => 0,
		'radio'  => 0,
		'link'   => 1,
		'theme'  => 1,
		'role'   => 'administrator',
		'unit'   => 1,
	);
	// if is active in network of multisite
	if ( is_multisite() && isset($_GET['networkwide']) && 1 == $_GET['networkwide'] ) {
		add_site_option( 'my_settings_id', $data );
	} else {
		add_option( 'my_settings_id', $data );
	}
}

The query of the value in the global GET can be integrated in the long time ago mentioned solution for Multisite and settings.

To solve other queries in a Multisite environment and to remove the setup or integrate menus in the admin area, the function is_plugin_active_for_network() is useful.

if ( is_multisite() && is_plugin_active_for_network( plugin_basename( __FILE__ ) ) )
	$values = get_site_option( 'my_settings_id' );
else
	$values = get_option( 'my_settings_id' );

Fortunately WordPress defines two constants which can help you to simplify things nonetheless: WP_PLUGIN_DIR and WP_PLUGIN_URL. These constants point to the plugin directory of the respective WordPress installation. They are defined since WordPress 2.6 and supporting older versions is most likely unnecessary
.
To make your plugins accessible to all your installed WordPress versions you simply move them to a central directory and define the constants accordingly:

define( 'WP_PLUGIN_DIR', '/var/www/plugins' ); // or with XAMPP C:/xampp/htdocs/plugins
define( 'WP_PLUGIN_URL', 'http://localhost/plugins' );

In this example the plugins reside in the directory 'plugins' in the root directory of the webserver. If you now define the above constants in every WordPress installation you have easy access to them to test your code with every version.

(Thanks to John Blackbourn on the wp-hackers list for having the idea.)

Hint for Multisite-Users

Also usable for WordPress Multisite

define( 'WPMU_PLUGIN_DIR', '/var/www/multisite-plugins' );
define( 'WPMU_PLUGIN_URL', 'http://localhost/multisite-plugins' );

The following small Plugin may extend to different roles or authorization objects, so that you can upload, depending on the role, different types of files in the system - current_user_can().

Anyone interested in the currently allowed types, you can return the array of the first function or look into the function get_allowed_mime_types() in wp-includes/functions.php.

<?php
/**
 * Plugin Name: Restrict mime types
 * Plugin URI:  http://wpengineer.com/?p=2369
 * Description: Restrict list of allowed mime types and file extensions.
 * Version:     1.0.0
 * License:     GPLv3
 * Author:      Frank Bültge
 * Author URI:  http://bueltge.de/
 */

 // This file is not called from WordPress. We don't like that.
! defined( 'ABSPATH' ) and exit;

// If the function exists this file is called as upload_mimes.
// We don't do anything then.
if ( ! function_exists( 'fb_restrict_mime_types' ) ) {

	add_filter( 'upload_mimes', 'fb_restrict_mime_types' );
	/**
	 * Retrun allowed mime types
	 *
	 * @see     function get_allowed_mime_types in wp-includes/functions.php
	 * @param   array Array of mime types
	 * @return  array Array of mime types keyed by the file extension regex corresponding to those types.
	 */
	function fb_restrict_mime_types( $mime_types ) {

		$mime_types = array(
			'pdf' => 'application/pdf',
			'doc|docx' => 'application/msword',
		);

		return $mime_types;
	}
}

// If the function exists this file is called as post-upload-ui.
// We don't do anything then.
if ( ! function_exists( 'fb_restrict_mime_types_hint' ) ) {
	// add to wp
	add_action( 'post-upload-ui', 'fb_restrict_mime_types_hint' );
	/**
	 * Get an Hint about the allowed mime types
	 *
	 * @return  void
	 */
	function fb_restrict_mime_types_hint() {

		echo '<br />';
		_e( 'Accepted MIME types: PDF, DOC/DOCX' );
	}
}

The following code belongs in the functions.php of the Theme, or better, in a Plugin. It adds the current favicon before the blog title. And to fit the image into the overall picture of the admin bar, we darkened it and and gave it a round shape.

<?php
/**
 * Plugin Name: Icon for Admin Bar Site Link
 * Plugin URI:  http://wpengineer.com/?p=2366
 * Description: Add Icon to Site Link in the WordPress Admin Bar
 * Version:	1.0.0
 * Author:      Sergej Müller
 * Author URI:  http://ebiene.de
 * License:     GPLv3
 */

// This file is not called from WordPress. We don't like that.
! defined( 'ABSPATH' ) and exit;
// If the function exists this file is called as comments template.
// We don't do anything then.
if ( ! function_exists( 'sm_add_adminbar_site_icon' ) ) {

	// add to admin area, inside head
	add_action( 'admin_head', 'sm_add_adminbar_site_icon' );
	// add to frontend, inside head
	add_action( 'wp_head', 'sm_add_adminbar_site_icon' );

	function sm_add_adminbar_site_icon() {

		if ( ! is_admin_bar_showing() ) {
			return;
		}

		echo '<style>
			#wp-admin-bar-site-name > a.ab-item:before {
				float: left;
				width: 16px;
				height: 16px;
				margin: 5px 5px 0 -1px;
				display: block;
				content: "";
				opacity: 0.4;
				background: #000 url("http://www.google.com/s2/u/0/favicons?domain=' . parse_url( home_url(), PHP_URL_HOST ). '");
				border-radius: 16px;
			}
			#wp-admin-bar-site-name:hover > a.ab-item:before {
				opacity: 1;
			}
		</style>';
	}

}

Also including comment-reply.js can be optimized. In the Theme TwentyEleven we can find it in header.php (Line 58):

if ( is_singular() && get_option( 'thread_comments' ) )
	wp_enqueue_script( 'comment-reply' );

That means, if "Enable threaded (nested) comments" in the Discussion Settings is activated and if it's on a single page, then load the script comments-reply.js.
But we also don't need the script on pages where there is no comment form and not on the homepage if it's a page. Neither do we need the script if comments are closed or not allowed.
Or easier to say: We only need it, if "Enable threaded comments" is activated and a comment form is displayed.

Using the example of TwentyEleven I show now how to do it better. First, we delete from the header.php the lines

if ( is_singular() && get_option( 'thread_comments' ) )
	wp_enqueue_script( 'comment-reply' );

In the functions.php we implement the enqueue function of the script

function xtreme_enqueue_comments_reply() {
	if( get_option( 'thread_comments' ) )  {
		wp_enqueue_script( 'comment-reply' );
	}
}

Now we get to the important part. We add to the function twentyeleven_setup() this line:

add_action( 'comment_form_before', 'xtreme_enqueue_comments_reply' );

The Hook comment_form_before is only there when the comment form is loaded and we are adding the enqueue function for the script. A positive side effect, the script is now loaded at the end of the document and does not hinder the loading of the site.
At best, you create a Child Theme, so the changes are protected against overwriting when you update WordPress the next time. Maybe the WordPress Dev team will use this approach in a future version of their default Theme TwentyEleven.

To help some people who are seeking help, here are some solutions you can work with. Some are to be used only in conjunction with WordPress, because the function comes from the core. But there are similar things, of course, even without WP.

The first solution can be found directly in the comments for the function of PHP.net.

$object = preg_replace( '!s:(\d+):"(.*?)";!e', "'s:'.strlen('$2').':\"$2\";'", $object );

Similar this approach:

$object = preg_replace( '/;n;/', ';N;', $object );

Alternative others prefer to use trim()

$object = trim( $object );

But even with these solutions you can't always get what you want, you need a queries which gives you the answer whether it is serialized data or not. Usually unserialize() takes care of it, but as I said, this does not always help. WordPress provides its own functions for this.

• is_serialized( $data )
• is_serialized_string( $data )

With these two functions it can be queried in a clean way.
But also there you can use a simple snippet. Not the best practice maybe, therefore, I prefer to use the functions or outside of WP, a separate function, see Gist 1415653.

$is_serialized = preg_match( "/^(O:|a:)/", $object );

It may help one or the other, otherwise I use it as a memory aid.