WordPress Static Front Page

Themes are a great way to showcase user content. Themes can often times add a bit of functionality to a site and that’s great! The hardest one to grasp is the use of a front page template. Yep, that can of worms. One of the common things I’ve noticed is authors creating two or more files with the same code. It hurts. The more common pattern of course is:

get_header();
	if ( get_option( 'show_on_front' ) == 'posts' ) {
        // If they want to show "Latests Posts"
		get_template_part( 'index', 'homepage' ) ;
	} elseif ( get_option( 'show_on_front' ) == 'page' ) {
        // otherwise we show the front page
		get_template_part( 'index' ) ;
	}
		
get_footer();

Or at least something close to that. They check in particular what the setting is. It’s this:

if ( get_option( 'show_on_front' ) == 'posts' ) { // code here }

That checks in particular what the user setting is. It basically says, if the user selected to use the latests post we run the following code. Usually it would be comprised of the amount of posts the user has set. Some like to show 5 post while some like showing 10. That doesn’t include stickies but I won’t get into that. That’s another can of worms not really worth opening right now.

There are several tutorials and other posts that are out there which can help you understand. One of my favorites is Chip Bennett’s on home page, front page, and templates. Really in-depth and a great starting point. If you don’t understand it, read it again. It will make sense eventually.

One thing I do find super weird is the way it checks. Not jump from the template hierarchy but in the way the query is as well. The core markup ( as of 4.3 ) is:

// @return bool True, if front of site.
public function is_front_page() {
    // most likely case
    if ( 'posts' == get_option( 'show_on_front') && $this->is_home() )
        return true;
    elseif ( 'page' == get_option( 'show_on_front') && get_option( 'page_on_front' ) && $this->is_page( get_option( 'page_on_front' ) ) )
        return true;
    else
        return false;
}

// @return bool True if blog view homepage.
public function is_home() {
	return (bool) $this->is_home;
}

It does two checks to make sure we are on the front of the site. Yeah a little odd but it does the trick. So, with that slight insight we can get a better understanding of how WordPress front-page, home, and index sort of fall into place.

Now, what can we do about it? The best method is using a filter. Yes. A filter. They are the lifeblood of any and all great themes and plugins. Use them like they are going out of style. Okay, perhaps a little extreme but they are super useful. I know that some people will be hesitant at first but once you get the hang of them and what to look for it will be a game changer for how you code.

The filter we’ll use is the get_query_template filter. This function/filter is found in the wp-includes/template file. The function is simplistic in nature and is filterable to your choosing. The code is:

function get_query_template( $type, $templates = array() ) {
	$type = preg_replace( '|[^a-z0-9-]+|', '', $type );

	if ( empty( $templates ) )
		$templates = array("{$type}.php");

	$template = locate_template( $templates );

	return apply_filters( "{$type}_template", $template );
}

So, let us break it down a little. This function accepts two arguments. The first one is required to be passed because it needs to know what file to look for otherwise it will give an error. The second one is an optional array of templates to look for. From there it will use locate_template to look first in the child theme for the file and if it doesn’t find it there it will use the parent folder to locate the template. Finally, we have our filter!

This is the fun part. In order to use the filter, we first have to know what template we would like to override. In our case it is the front-page.php; though it does something a little odd, in that it removes the - so we need to use frontpage as the template name. So the filter hook would look like:

add_filter( 'frontpage_template', 'jc_frontpage_template' );

Super simple, right? Now to write out the logic, or our callback function. In that function all we have to return is a string of where our replacement file is. Let’s say that we have a landing page that we would like to use. Just don’t forget to document that otherwise people may get confused on the unexpected behavior. In order to do so we can use something like:

function jc_frontpage_template( $template ){
	if ( is_home() ){
		get_home_template();
	} else {
		return locate_template( 'templates/landing.php' );
	}
}

Pretty sweet, right? I think so. So, go, explore those filters, break things and learn from it.

Using active callbacks in the Customizer

One thing I haven’t seen many themes use is active callbacks to their advantage. What are they and how can they used? It’s actually quite simple and there are two methods that the customizer has available. The first one is when you first create the section, panel, or control.

$wp_customize->add_section( 'meta-slider-section',
	array(
		'title' => __( 'Meta Slider Section', 'jc-domain' ),
		'description' => __( 'Input the ID of a slider and it will display on this section of the theme', 'jc-domain' ),
		'active_callback' => 'is_meta_active',
	)
);

Great! We have a section but how do make sure that it will only be seen when the plugin is active? The 'active_callback' function will be used. In that function we can setup our logic so that the section will only show if the meta slider plugin is active.

function is_meta_active(){
	// Check for the slider plugin class
	if( !class_exists( 'MetaSliderPlugin' ) ) {
	// If it doesn't exist it won't show the section/panel/control
		return false;
	} else {
	// If it does, we do show it
		return true;
	}
}

Fairly neat right? What’s really awesome is that you can do this with controls as well. Let’s say we want a control to only show with a specific page template. You can use the callback function to look something like:

function is_certain_page_template() {
	// Get the page's template
	$template = get_post_meta( get_the_ID(), '_wp_page_template', true );
	$is_template = preg_match( '%fullwidth.php%', $template );	if ( $is_template == 0 ) {
		return false;
	} else {
		return true;
	}
}

Now, I mentioned there are two methods of using active callbacks. The second method is by using an extending class. Let’s say we have a custom control class that we only want to show when an option is selected.

Now, I mentioned there are two methods of using active callbacks. The second method is by using an extending class. Let’s say we have a custom control class that we only want to show when an option is selected.

if ( class_exists( 'WP_Customize_Manager' ) ):
class JC_Manic_Control extends WP_Customize_Control {
	function active_callback(){
		// This is the function that will house the logic so our control
		// shows only when we need it to. This will override the
		// WP_Customize_Control's active_callback function.
		return false;
	}
	function render_content(){
		// other code goes here, keeping it simple for demonstration purposes.
	}
}
endif;

Pretty darn cool if you ask me. Now, with those two methods you can create a much better experience with your theme options and customizations. So, go on and explore and experiment with active callbacks. Add it to your repertoire of theme tools and WordPress knowledge!

Two or three column section

A while back I wrote a quick and dirty tutorial on how to display more than one page. This can be done in a number of different ways. You can read about them in other tutorials and guides because this time I’ll go over another method using the WP_Query method. The codex page some really great ways and examples of using it to your advantage, I highly recommend you give it a skim and return to this.

So, on to the code!

What I’ll be using is a switch statement, an active callback, and of course the customizer API.

First we will create the settings and controls:

$wp_customize->add_section( 'demo-front-sections',
				 array(
					 'title' => __( 'Front page sections', 'text-domain' ),
					 'description' => __( 'Choose what pages to show on the front page panels', 'text-domain' ),
					 'priority' => 1,
					 'active_callback' => 'is_front_page'
				 ) );
$wp_customize->add_setting( 'col-count',
				 array(
					'default' => 2,
					'sanitize_callback' => 'absint'
				 ) );
$wp_customize->add_control( 'panel-count',
				 array(
					'settings' => 'col-count',
					'label' => __( 'How many panels on this section', 'text-domain' ),
					'type' => 'radio',
					'choices' => array( '2' => 2, '3' => 3 ),
					'section' => 'demo-front-sections',

				 ) );

// Register the page settings to get the IDs
$wp_customize->add_setting( 'page-1',
				 array(
					'default' => 0,
					'sanitize_callback' => 'absint'
				 ) );
$wp_customize->add_setting( 'page-2',
				 array(
					'default' => 0,
					'sanitize_callback' => 'absint'
				 ) );
$wp_customize->add_setting( 'page-3',
				 array(
					'default' => 0,
					'sanitize_callback' => 'absint'
				 ) );

// Set the controls
$wp_customize->add_control( 'panel-1',
				 array(
					 'settings' => 'page-1',
					 'label' => __( 'Pick what page you would like to showcase', 'text-domain' ),
					 'type' => 'dropdown-pages',
					 'section' => 'demo-front-sections'
				 ) );
$wp_customize->add_control( 'panel-2',
				 array(
					 'settings' => 'page-2',
					 'label' => __( 'Pick what page you would like to showcase', 'text-domain' ),
					 'type' => 'dropdown-pages',
					 'section' => 'demo-front-sections'
				 ) );
$wp_customize->add_control( 'panel-3',
				 array(
					 'settings' => 'page-3',
					 'label' => __( 'Pick what page you would like to showcase', 'text-domain' ),
					 'type' => 'dropdown-pages',
					 'section' => 'demo-front-sections',
					 'active_callback' => 'panel_countcheck'
				 ) );

You’ll notice I used a basic active callback for the section so that the section will only show up on the front page. You may also notice that I’ve added a callback to the third control. We haven’t created that callback so let’s do it:

function panel_countcheck( $value ){
	if ( get_theme_mod( 'col-count' ) > 2 ){
		return true;
	}
	return false;
}

Great! Now what does it do? Let’s break it down a little. So, if the first value ( col-count ) is greater than 2, then let’s show this control, otherwise we won’t. Pretty self-explanatory, right?

Great now we just need to display this on a page template, or the front page ( in our case ). We use get_theme_mod to get the values and the code will look a little like:

// get setting for how many
$count = intval( get_theme_mod( 'col-count', 2 ) );
// create an array for the new query
$ids= array();
// get the pages
$ids[] = intval( get_theme_mod( 'page-1', 0 ) );
$ids[] = intval( get_theme_mod( 'page-2', 0 ) );
if ( $count > 2 ){
	$ids[] = intval( get_theme_mod( 'page-3', 0 ) );
}

$query = new WP_Query( array( 'post_type' => 'page', 'post__in' => $ids, 'orderby' => 'post__in' ) );

switch( $count ){
	case 2:
		while( $query->have_posts() ): $query->the_post();
			echo '<div class="col-2">';
				the_title( '<h2>', '</h2>'); the_content();
			echo '</div>';
		endwhile;
	wp_reset_postdata();
	break;
	case 3:
		while( $query->have_posts() ): $query->the_post();
			echo '<div class="col-3">';
				the_title( '<h2>', '</h2>'); the_content();
			echo '</div>';
		endwhile;
	wp_reset_postdata();
	break;
}

Yeah, it is a little messy but we will break it down and explain what does what.

The first setting we get is the column count. You’ll see that I am using intval because we want to make sure that we are setting an integer. The value being passed from the customizer setting is an ID number that corresponds to a page ID, so we make sure that it really is an integer.

$count = intval( get_theme_mod( 'col-count', 2 ) );

Next up, we get our pages and build up the array that we will pass our new WP_Query. As you can see, we first get the first two pages and conditionally add the third if the $count is greater than 2. Remember this is the setting that the user picks.

$ids[] = intval( get_theme_mod( 'page-1', 0 ) );
$ids[] = intval( get_theme_mod( 'page-2', 0 ) );
if ( $count > 2 ){
	$ids[] = intval( get_theme_mod( 'page-3', 0 ) );
}

From there, we build up the new query. Pretty simple. We make sure that the post type is a page, and the order is maintained by what we pass it.

$query = new WP_Query( array( 'post_type' => 'page', 'post__in' => $ids, 'orderby' => 'post__in' ) );

Now we get to the switch statement! This is where the fun sort of begins.

switch( $count ){
	case 2:
		while( $query->have_posts() ): $query->the_post();
			echo '<div class="col-2">';
				the_title( '<h2>', '</h2>'); the_content();
			echo '</div>';
		endwhile;
	wp_reset_postdata();
	break;
	case 3:
		while( $query->have_posts() ): $query->the_post();
			echo '<div class="col-3">';
				the_title( '<h2>', '</h2>'); the_content();
			echo '</div>';
		endwhile;
	wp_reset_postdata();
	break;
}

Okay. Let’s look over the lines a bit. As you can see we pass it the $count variable we first created, which houses the option of whether to show 2 pages or 3. We create a case for each one and as you can see the only real difference here is the class. For showing two pages it is 2-col and for the 3 it is 3-col. You can create a quick wrapper for that if you want so it can be extended by a child theme like:

function jc_classes(){
	$classes = array();
	$classes[] = 'span';
	$cols = get_theme_mod( 'col-count', 2 );
	switch( $cols ){
		case 2:
		$classes[] = 'col-2';
		break;
		case 3:
		$classes[] = 'col-2';
		break;
	}
	
	return 'class="' . esc_attr( implode( ' ', apply_filters( 'jc_custom_classes', $classes ) ) ) . '"';
}

From there we can lose the switch statement and use:

$query = new WP_Query( array( 'post_type' => 'page', 'post__in' => $ids, 'orderby' => 'post__in' ) );
while( $query->have_posts() ): $query->the_post();
	echo '<div ' . jc_classes() .'>';
		the_title( '<h2>', '</h2>'); the_content();
	echo '</div>';
endwhile;
wp_reset_postdata();

What’s really nice is you can use basic CSS to style it. A quick snippet:

.col-2 {
	float: left;
	width: 50%;
}

.col-3 {
	float: left;
	width: 33%;
}

So, go on, experiment, and fiddle around with the code a bit. Do remember I used basic things, so be sure to add the proper settings, text, and values for your needs.

Customizer: dropdown category selection

This is just a quick code snippet that may help at least one person. I know it will. Earlier today I was looking over a theme and it was driving me crazy to see them re-inventing the wheel. A simple dropdown that core uses in order to display the categories. The way core uses choices is an associative array. The array key is the $value and the array value is used for the label. What does this mean?

It means that often times you have to flip things around because core can get certain values in a different manner. A great example is the get_page_templates function. The following is one way of creating this array.

// we get all the available templates
$templates = array_flip( get_page_templates() );

// new array is
$templates = 
	array (
	'templates/home.php' => 'home',
	'templates/featured.php' => 'featured posts',
	'templates/widgetized.php' => 'Widgetized Page'
	)

Do keep in mind that is just for that particular function. There are several other functions that return either arrays or objects, so it is in your best interest to learn how and what each function returns data. I say this because the above code uses a basic PHP function in order to re-create the array. The function itself returns things the other way around. The codex page does a good job of explaining it.

In this post we will go over the get_categories function. It returns an array but not the way we want in order to use in the customizer. In order to do so we have to get a little creative in building the array.

// create an empty array
$cats = array();

// we loop over the categories and set the names and
// labels we need
foreach ( get_categories() as $categories => $category ){
	$cats[$category->term_id] = $category->name;
}

// we register our new setting
$wp_customize->add_setting( 'cats_elect', array(
	'default' => 1,
	'sanitize_callback' => 'absint'
) );

// we create our control for the setting
$wp_customize->add_control( 'cat_contlr', array(
	'settings' => 'cats_elect',
	'type' => 'select',
	'choices' => $cats,
	'section' => 'my_section',  // depending on where you want it to be
) );

This will return an integer for the category. Hence the absint sanitation callback. From there all we would have to do to get our setting is use:

$cat_id = intval( get_theme_mod( 'cats_elect', 1 ) );

You’ll notice I’ve used intval around the get_theme_mod function, that is so we make sure that we are getting an integer from our saved setting just in case. You can never be too careful, right?

So, there you have it! Just a few lines of code and we have a dropdown of our categories.

Working with the WordPress Customizer

Recently the Theme Review Team chose to make the customizer as the format of creating theme options. I love it! Yes, I was in favor of it. I have my reasons. I know there are some people that still don’t fully grasp the customizer and most likely won’t. All good! Some take a little more time than others; I know I do sometimes with certain things.

How it works

Okay. This little post will deal with customizer settings, controls, sections and panels. Yes. At the time of this writing the WordPress version is 4.2.1 with 4.3 just beginning. In the following I will make an attempt at giving you ( the reader ) a little more insight into how the WordPress customizer works and what is available within the customizer.

In order to understand the customizer a little more I dove into the core code. I asked myself a simple question, “when and where is it being created?”

Funnily enough it is done in one simple function. _wp_customize_include. It is a callback function that is hooked to plugins_loaded. Yes, I went ahead and looked up a lot of the code for you. What’s pretty cool is that in order for the customizer to work it needs five files. Yes, five. To a degree 7 but the other two are the customize.php and class-wp-customize-widgets.php files. For the purpose of this post I’ll only really dive into the five customizer ones.

Let’s look at the function:

function _wp_customize_include() {
	if ( ! ( ( isset( $_REQUEST['wp_customize'] ) && 'on' == $_REQUEST['wp_customize'] )
		|| ( is_admin() && 'customize.php' == basename( $_SERVER['PHP_SELF'] ) )
	) )
		return;

	require( ABSPATH . WPINC . '/class-wp-customize-manager.php' );
	// Init Customize class
	$GLOBALS['wp_customize'] = new WP_Customize_Manager;
}

The key thing to remember is when you are creating your options, you are passing an object. The $wp_customize global object to be a little more specific. As you can tell from the function above, you are creating an instance of the WP_Customize_Manager and setting that as the $wp_customize global variable that can be accessed by using:

global $wp_customize;

Looking at the __construct method, it loads the needed files and adds a few filters and hooks in order for the magic to happen. Totally awesomesauce!

Boom! We have our customizer! Great! But how do we add stuff?

Adding things

In order to add our theme options we have to hook to the right place. The codex has a great explanation on this, though currently it is missing a section on how to add panels. Yes, you can add panels in order to make your theme option logic make some sense for a user.

So, in order to add things we need to know how, right? Right! What’s pretty neat is that the customizer does this with built in methods. Yes, it is very object oriented. One of the other reasons I like it. There are four methods that will help in creating a great customizer experience.

$wp_customize->add_setting();
$wp_customize->add_control();
$wp_customize->add_section();
$wp_customize->add_panel();

I say customizer experience because as a developer you will have to think about the logic of your theme options. That’s great and all but what actually starts it all? The part that we hook to in order to start our theme options is the customize_register hook. This is done from within your theme by using:

add_action( 'customize_register', 'my_theme_customize_regiter' );
function my_theme_customize_register( $wp_customize ){
	// Theme settings/options code goes here
}
// or if using a class
add_action( 'customize_register', array( 'My_Class_customize_register', 'register' ) );
class My_Class_customize_register {
	public function register(){
		// Theme settings/options code goes here
	}
}

Got it? Cool! Let’s keep moving! Let’s break down each method a little more.

The methods

What’s super cool is that the customizer makes it super easy to create a theme option experience. It does this with four different methods. Let’s take a look at each one and what each one has to offer.

add_setting

The first one we will look at is the settings. In order to create a theme option in the customizer we use the $wp_customize->add_setting method. It takes two arguments. The first one is the ID of the setting and the second is an associative array. It looks a little like:

$wp_customize->add_setting( 'theme_option', array(
	'default' => '', // The default setting
	'type' => '', // can use 'theme_mod' or 'option'
	'capability' => '', // generally 'edit_theme_options'
	'transport' => '', // can use 'refresh' or 'postMessage'
	'theme_supports' => '', // internally used in customizer
	'sanitize_callback', // the callback before setting is saved to database
	'sanitize_js_callback' => '' // used for the JS value
	) );

You don’t have to use all of them. The ones that matter most are the default, option, transport, and sanitize_callback arguments. The reason option is one that matters is in the way it will save the options into the database. The sanitize_callback matters because it runs before the setting is saved to the database so you have to make sure to sanitize it. The transport value can be important if you want the page to do a full refresh or if it will be AJAXified.

add_control

The next one to look at is the $wp_customize->add_control. This is what the user will see. Much like the add_setting it, too, we have to pass two arguments. The first one being a unique ID, and the second being an associative array.

$wp_customize->add_control( 'option_control', array(
	'label => '', // label for the control
	'description' => '', // description of the control
	'settings' => '' // the setting 
	'section' => '', // core ones are: 'title_tagline', 'colors', 'header_image', 'background_image', 'nav', 'static_front_page'
	'type' => '', // core ones include: 'checkbox', 'radio', 'select', 'textarea', 'dropdown-pages', 'text'
	'choices' => array(), // associative array of 'value' => 'option user sees'
	'priority' => '', // the higher the number the lower it will appear from the top
	'input_attrs' => array(), // associative array of 'attr' => 'value'
	'active_callback' ='' // based on preview context
	) );

So, we have a few options with the controls. Cool, right? What’s even cooler is that there are few others to use. You can also use WP_Customize_Image_Control, WP_Customize_Upload_Control, WP_Customize_Color_Control, and WP_Customize_Media_Control. They just require a little extra code.

$wp_customize->add_control( new WP_Customize_Media_Control( $wp_customize, 'media_control', array(
	'label' => 'Image selection',
	'description' => 'Choose an image',
	'settings' => 'default_value',
	'section' => 'random_slider'
) ) );

add_section

Great! Now that we know how to create a setting and a control, we can look at how to create a section to hold those settings. You’ll notice I’m using settings and options a little interchangeably. As stated earlier you can choose how to save things to the database. The theme_mods or option. How you do it is up to you. Now, let’s look at how to create a section, shall we? This too, like the previous two takes two arguments. A unique ID and an associative array.

$wp_customize->add_section( 'my_section', array(
	'title' => '', // the title of the section
	'description' => '', // description of the section
	'priority' => '', // the higher the number the lower in the customizer from the top
	'capability' => '', // default setting is 'edit_theme_options'
	'panel' => '', // if none it will show on main panel
	'active_callback' => '' // based on preview context
	) );

Simple and fairly straight-forward, right? What’s pretty cool too is that you can use the active_callback to your advantage. For example if you wanted to show a certain section only a widgetized area was being used. You could use a callback like:

// in the customizer
'active_callback' => 'widgetized_cb'
// later on in the code
function widgetized_cb(){
	return is_active_sidebar( 'primary' );
}

add_panel

Pretty awesome right? See where some of that logic can come into play? Great! Now you know how to add settings, controls, and sections. We can finally take a look at the final one: panels!

What’s super awesome is that this, too, uses two arguments. A unique ID and an associative array. Notice a pattern here? Let’s look at the available ones:

$wp_customize->add_panel( 'my_panel', array(
	'title' => '', // the title for the panel
	'description' => '', // short description of the panel
	'priority' = '', // the higher number, the lower from the top
	'active_callback' => '' // based on preview context
	) );

As you can see not a lot for the panels – yet. The customizer is constantly being worked on in core. There are a lot of things you can do to make it better if you want to help out.

Previewing

Okay, this is the part where things really come together because it deals with JavaScript. You remember in the add_setting there was an option for transport? If you want to create live previews without the entire page being refreshed, you set it to postMessage. In order for it to take place you will have to include a little JavaScript. I would highly recommend using a dedicated file for this. All you have to do is hook to the right place and enqueue it.

add_action( 'customize_preview_init', 'my_theme_preview' );
function my_theme_preview(){
	wp_enqueue_script( 'my-theme-js-preview-file', get_template_directory_uri() . '/js/my.customize.preview.js', array( 'customize-preview' ), '', true );
}

From there your JavaScript file would include something like:

wp.customize( 'setting_id', function( value ) {
	value.bind( function( newvalue ) {
		// do things
	} );
} );

Final thoughts

So there you have a slight crash course on how the customizer works and what options are available to create a good theme option user experience. There are a few little tricks and things you can also do, so go ahead and explore the core code and find out! You’ll be amazed at what you will find.

Fun with template tags: comment_form

This time I’ll focus on the comment_form(). Neat, fun and with plenty of hooks and filters.

The code

Like usual we will look at the core code of the comment_form. There are approximately 230 lines of code that make up this template tag. Does sound like a lot, right? Yes, but when you look a little closer it is the inline documentation that makes up the brunt of it all.

Yes, documentation. I love it and is what I am doing to an extent with these posts. I am documenting their use with examples in hopes that somebody finds it useful. I know at least one person will.

Anyway, back to the point. The hooks and filters.

The filters

One of the first filters is comment_form_default_fields. Pretty neat one because you can add, remove, and even edit form fields. Let’s make a quick edit and remove the website field from the default, shall we?

add_filter( 'comment_form_default_fields', 'my_new_fields' );
function my_new_fields( $fields ){
	$fields['author'] = '<p class="author input"><label for="name"><span class="required">Your name:</span></label><input name="name" type="text" /></p>';
	
	unset( $fields['url'] );
	return $fields;
}

Pretty neat, right? The next one that we come across is the comment_form_defaults. This one is a little more fun in that it has the previous one included with it. I know you may be thinking what do I mean by that, so let’s look at the code:

$defaults = array(
	'fields' => $fields,
	'comment_field' => '<p class="comment-form-comment"><label for="comment">' . _x( 'Comment', 'noun' ) . '</label> <textarea id="comment" name="comment" cols="45" rows="8" aria-describedby="form-allowed-tags" aria-required="true" required="required"></textarea></p>'

That $fields variable is from the previous filter. It is the line before the $defaults array is set. So much like the previous filter we can edit and remove from the default comment_form.

add_filter( 'comment_form_defaults', 'my_custom_form' );
function my_custom_form( $array ){
	$array['class_submit'] ='submit blue input';
	$array['title_reply'] = __( 'Drop us a line', 'text-domain' );
	$array['title_reply_to'] = __( 'Argue with %s', 'text-domain' );
	$array['cancel_reply_link'] = __( 'nevermind!', 'text-domain' );
	
	return $array;
}

From the above example you can see we change the submit class to include blue and input. A few other things were changed and the best part is that you can use a child theme to remove that or even add your own. That’s cool if you wanted to make a lot of additions or deletions but what if you wanted to do it to just one? That’s where

echo apply_filters( "comment_form_field_{$name}", $field ) . "\n";

comes into play. Where $name is the input you wanted to edit. For example:

add_filter( 'comment_form_field_author', 'my_new_author_field' );
function my_new_author_field(){
	return '<label for="author">' . __( 'What is your name, yo?', 'text-domain' ) . '<span class="required">*</span></label><input id="author" name="author" type="text" size="30" />';
}

Pretty cool if you have to change a few thing in order to properly style your form elements.

The hooks

Cool! Those were some of the filters but we cannot just leave without a few action hooks, right? I mean why wouldn’t you like action hooks? Those are so cool because you can add things conditionally.

Let’s look at some of them shall we? There are nine in total. Yes, 9. Not nine thousand. Just nine. That’s quite a few that we can hook to. Good! Plenty of things to mess and tweak with. Some of the neater ones I like are:

do_action( 'comment_form_before' );
do_action( 'comment_form_top' );
do_action( 'comment_form_before_fields' );
do_action( 'comment_form_after_fields' );
do_action( 'comment_form', $post_id );
do_action( 'comment_form_after' );

The reason I like the fifth one is because it is a dynamic one. You can add to the form depending on the post’s ID. Let’s say you wanted to add a note to all posts published before a certain date. You could potentially go through every single one but that could be time consuming. What’s nice is that WordPress uses an incremental ID meaning that when a new post is added it uses the next highest number for the ID. You could use something like:

add_action( 'comment_form', 'my_form_notice' );
function my_form_notice( $id ){
	if ( $id < 1155 ){
		printf( '<span class="notice">%s</span>', __( 'This post may be outdated', 'text-domain' ) );
	}
}

Do keep in mind that some of the above mentioned methods could be used for both plugins as well as themes so use them wisely.

Fun with template tags: comments_template

On my last post I talked about dynamic_sidebar and some uses. It was a fun little experiment I wanted to do and share. Yes, I said experiment. That is how I learn. I read, do and then share. I know I’m not the only one that does that.

This time I dabbled with comments_template(). Yes, another one of the more common template tags. I wanted to dissect the function and see what really makes it unique. Okay, not really, I more or less wanted to look at the code and see how it gets the template file.

Core code

The code itself is about 90 lines. That is including the inline documentation. Without the inline documentation it is about 60 lines. Good to know. It means we don’t have to guess what is going on a lot. So let’s dive in shall we?

Okay, let’s break the function down, shall we?

The arguments

The first argument that is passed is the $file location. The second is whether or not to separate the comments. Simple. But what does that mean and how can we change this?

One way, of course is by passing some arguments ourselves. Let’s say we wanted to separate the comments, we would use:

<?php comments_template( '', true ); ?>

Or if we had our comment template in another location we would use:

<?php comments_tempate( '/inc/comments.php' );

That’s great if your comment template resided in the inc folder and was named comments.php. But what happens if you don’t have a comments.php file anywhere in your theme’s folder? Well, the nice part is that WordPress does account for that. The downside is that it creates a deprecated_file call. Yes, an error. If you read the following doc-block you can see why.

/**
 * @package WordPress
 * @subpackage Theme_Compat
 * @deprecated 3.0
 *
 * This file is here for Backwards compatibility with old themes and will be removed in a future version
 *
 */

I’m going to emphasize the part that really matters most:

and will be removed in a future version

Backwards compatibility is one thing that WordPress does really well; though this is one time I wish it would do it faster. At least for these files. There are a few other files but I’ll focus on this for now.

But why does it load that file if there is no comments.php file? Let’s look a little closer at what the function actually does. At least the parts that really make it load the needed file.

if ( empty($file) )
	$file = '/comments.php';

$theme_template = STYLESHEETPATH . $file;

$include = apply_filters( 'comments_template', $theme_template );
if ( file_exists( $include ) )
	require( $include );
elseif ( file_exists( TEMPLATEPATH . $file ) )
	require( TEMPLATEPATH . $file );
else // Backward compat code will be removed in a future release
	require( ABSPATH . WPINC . '/theme-compat/comments.php');

Not really much code, right? First it checks if the passed argument $file is empty and if it is it creates a simple string of '/comments.php'. Then, it creates a variable $theme_template with the constant TEMPLATEPATH and $file appended to it. Next we see a fairly familiar function apply_filters(). The filter name is comments_template.

We can then use a filter hook to change the location of our comments template. Granted we can do the same without even using the filter by simply passing it the location string to the function itself as we saw above, right?

It matters

Why am I bringing this up? I am bringing this up because the comments template file should be the place to be using wp_list_comments() as well as comment_form(). It doesn’t have to be comments.php that houses those template tags. It could be named anything you want, you just have to make sure you are loading the file properly.

Using a filter

One way is using a filter hook. As you noticed above the line:

$include = apply_filters( 'comments_template', $theme_template );

This what we can use. The code would look a little something like:

add_filter( 'comments_template', 'demo_path_to_comments_template' );
function demo_path_to_comments_template( ){
	if ( is_child_theme() && file_exists( get_stylesheet_directory() . '/inc/coms.php' ) ){
		return get_stylesheet_directory() . '/inc/coms.php';
	} else {
		return get_template_directory() . '/inc/coms.php';
	}	
}

Yes, quite a bit just for comments, right?

Using an argument

What’s super cool about using the core template tag and passing it the argument is that it will first look in the child theme ( if active ) and then the parent theme for the file you designate.

<?php comments_template( '/comments/pings.php', true ); ?>

In the above example it will first look for the pings.php file of the child theme ( if it is active ) and if that file does not exist it will load the parent file. Sort of what get_template_part() does. That is another neat little function for another post.

Seriously, it matters

I’m going to repeat this part because it bears repeating. The backwards compatibility file will one day be removed. Your users will thank you for not using the fallback file. It shouldn’t be a safety net for the theme. Besides, if you want the theme to be hosted in the repository it can’t have any errors.

Fun with template tags: dynamic_sidebar

The last couple of weeks I’ve been reading the core code more and more. I like it. Came to the conclusion I really don’t know every hook or filter. I don’t claim to though. I like knowing enough to make a functional theme or even a plugin. Yes, I’ve been recently dabbling with one but that’s for another post.

The reason for this post is to share some knowledge. Hopefully somebody finds this useful or helpful.

The function

For this post I will be using dynamic_sidebar(). It’s a fairly common template tag in themes. It gets a widgetized area and outputs them in a designated area. In order for that to happen you must first have a registered area. We do that by using register_sidebar(). For demonstrational purposes we will use:

register_sidebar( array(
	'name'          => __( 'Footer Area', 'dademo' ),
	'id'            => 'footer-area',
	'description'   => __( 'Add widgets here to appear in your sidebar.', 'dademo' ),
	'before_widget' => '<aside id="%1$s" class="widget %2$s">',
	'after_widget'  => '</aside>',
	'before_title'  => '<h2 class="widget-title">',
	'after_title'   => '</h2>',
) );

Great! So we created a widgetized area with an ID of footer-area. It can be anything we want but we will currently stick to simple naming conventions. Now, let us look at the core code, shall we?

The core code

The function itself is quite a few lines of code. Approximately 160 lines. I’m not going to post all of that code. The developer reference page has it and you can even view on trac. The ones that matter most for this post are two lines.

The first line:

do_action( 'dynamic_sidebar_before', $index, true );

The second line:

do_action( 'dynamic_sidebar_after', $index, true );

Notice something a little strange about it? I’m referring to the $index part of course. This is the neat part of it all. What does that little part mean?

Our hook

The cool part is that you can hook to specific widgetized areas if you want. I know you may be asking what I mean by this so I’ll demonstrate a little bit. Take our previous example of footer-area above and we will wrap it within a <section> element tag with a class of row.

add_action( 'dynamic_sidebar_before', 'demo_sidebar_before' );
function demo_sidebar_before( $index ){
	if ( $index == 'footer-area' ){
		echo '<section class="row">';
	}
}
add_action( 'dynamic_sidebar_after', 'demo_sidebar_after' );
function demo_sidebar_after( $index ){
	if ( $index == 'footer-area' ){
		echo '</section><!-- Widgetized footer area -->';
	}
}

From there it would render:

<section class="row">
	<aside id="recent-posts-4" class="widget widget_recent_entries">
	<h2 class="widget-title">Recent Posts</h2>
	<ul>
		<li>
		<a href="/2015/04/13/aesop-testing/">Aesop testing</a>
		/li>
		<li>
		<a href="/2015/04/13/sampling-some-code/">Sampling some code</a>
		</li>
		<li>
		<a href="/2015/04/08/another-gallery/">another gallery</a>
		</li>
		<li>
		<a href="/2015/04/08/gallery-7/">gallery 7</a>
		</li>
		<li>
		<a href="/2015/04/08/gallery-6/">gallery 6</a>
		</li>
	</ul>
	</aside>
</section><!-- Widgetized footer area -->

As you can see it created the section element and inside of it is a simple recent posts widget. Now, as I mentioned that is for specific widgetized areas. The thing to remember is to use the ID of the widgetized area to conditionally add or remove. It is that $index that is used to test. You can add things to every single dynamic_sidebar call by not even checking. Let’s say we have two widgetized areas. One in the footer and the other just above the content. We will call that section, “content-above.”

I know, very creative. I said it would be simplistic, didn’t I?

Okay, we wanted to add few things. Let’s say we wanted to add an image to both of those sections. We could edit two different files depending on how your theme is structured. Sounds a little painful, right? So, we will use our handy-dandy little hook:

add_action( 'dynamic_sidebar_before', 'demo_sidebar_before' );
function demo_sidebar_before( $index ){
	echo '<section class="row">';
	echo '<img src="' . get_template_directory_uri() . '/img/divider.png" />';
}
add_action( 'dynamic_sidebar_after', 'demo_sidebar_after' );
function demo_sidebar_after( $index ){
	echo '</section><!-- Widgetized area with image -->';
}

Pretty cool, right? What’s super cool is it will render like:

<section class="row">
<img src="path/to/img" />
<!-- widgets -->

</section><!-- Widgetized area with image -->
<section class="content row">
<!-- the_content -->
</section>

<section class="row">
<img src="path/to/img" />
<!-- widgets -->
</section><!-- Widgetized area with image -->

Yes, all that markup where ever you are using dynamic_sidebar().

Advanced fun

This part I’m writing as my left eye is twitching only because it deals with widgets in themes. Yes, I’ve never liked including them. This part deals with hooking to particular widgets in your theme.

Yes, you could simply edit the file that has the widget but where is the fun in that? This time we will use an action hook.

add_action( 'dynamic_sidebar', 'demo_sidebar' );
function demo_sidebar( $obj ){
	
	if ( $obj['callback'][0]->id_base == 'meta' ){
		printf( '<span>%s</span>', __( 'So much meta', 'dademo' ) );
	}
	// Alternatively
	// if ( preg_match( '/meta-/', $obj['id'] ) ){
	//	printf( '<span>%s</span>', __( 'So much meta', 'dademo' ) );
	// }
}

Does look a little complex, right? Let’s break it down a little.

First, we create the hook in line 1. Then we create our callback function in line 2. Doing good so far. Line 3 is where it does get a little odd. What does it mean? What does it mean?!

Okay, it may look a little complex to some but I’ll explain a little bit more.

When using dynamic_sidbar() it uses an array for the widgets. If there are no widgets then the function returns a false value. If there are it creates an associative array of the widget instance. That array is what we pass our callback function. In the example it is called $obj. In that array we have a key called callback. It, too, is an array.

We are looking for the first item on there because it holds the important part. The information about the widget object. The example is looking for the id_base of the widget. You know that little part you named when you registered the widget.

The alternative uses preg_match to match the ID of the widget’s instance. Yes, you can do specific instances as well.

Using the_post_thumbnail

For some time I’ve noticed one thing that many people like doing. Recreating core functions. One being the_post_thumbnail(). The reason it drives me crazy is because it means maintaining more code in your theme. Why would you do that to yourself? One of the common things is to wrap it in a conditional check and then use the function if there is a thumbnail. Great! Looks like:

if ( has_post_thumbnail() ){
	the_post_thumbnail();
} else {
	custom_post_thumbnail();
}

The problem

Rewriting a core template tag to suit the theme’s design. Yes, it drives me insane when I know that there is a filter or a hook that can be applied to core functions. Yes. Core has a lot of hook and filters to modify. I’m not saying learn them all but merely suggesting look at the core code when you want to see what and how things are done.

Core file

In order to create our little function let us look at the actual core code, shall we? All the workings are actually placed in the wp-includes/post-thumbnail-template.php file. A little crazy, right? Let’s take a look at the code:

function the_post_thumbnail( $size = 'post-thumbnail', $attr = '' ) {
	echo get_the_post_thumbnail( null, $size, $attr );
}

There it is. So what does it do? It creates a default size ( post-thumbnail ) and passes a null argument to get_the_post_thumbnail. A little weird but makes sense, right? So let’s look at the actual function that gets us the image, yeah?

function get_the_post_thumbnail( $post_id = null, $size = 'post-thumbnail', $attr = '' ) {
	$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
	$post_thumbnail_id = get_post_thumbnail_id( $post_id );

	$size = apply_filters( 'post_thumbnail_size', $size );

	if ( $post_thumbnail_id ) {

		do_action( 'begin_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );
		if ( in_the_loop() )
			update_post_thumbnail_cache();
		$html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );

		do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );

	} else {
		$html = '';
	}

	return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );
}

As you can see it looks like quite a bit. So we will break it down a little bit more. Go down the lines and explain a little more.

Breakdown: the arguments

The first thing you will see is that it asks for a $post_id, then an image size and an attribute. Cool. Still with me? Good. Now let’s move on to the next line of code:

$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;

It tests if the $post_id is identical to null and if it is, we get the post’s ID by using get_the_ID(). Pretty neat if you ask me.

Next, it passes that ID to get_post_thumbnail_id in order to get the image’s attachment ID. You read it right.

The next line is where we come across our first filter. Yay! And it is post_thumbnail_size. What this means is that if you wanted to use

the_post_thumbnail( 'my-theme-image' );

You can add a filter and make it a conditional setting as well. You can use:

add_filter( 'post_thumbnail_size', 'my_new_sizes' );
function my_new_sizes( $size ){
	if ( is_front_page() || is_home() ){
		return 'my-large-front-image';
	}
	return 'my-theme-image';
}

Awesome, right? I like to think so. The next several lines are what create the actual code.

First it checks if it is a true value and if it is we can continue with our code. Then we see an interesting line:

do_action( 'begin_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );

Kind of a neat little hook. You can print things just before the image tag. From there it updates the thumbnail cache, and then finally it gets the image’s markup by using wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr ). Cool, right? Right. But we are not done just yet.

We have another hook:

do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );

With this particular one you can also print things out before the image’s markup. For example:

add_action( 'end_fetch_post_thumbnail_html', 'demo_before_image' );
function demo_before_image(){
	_e( 'I appear before the image', 'textdomain' );
}

The end result will be:

I appear before the image<img width="522" height="270" src="http://sample.dev/wp-content/uploads/2013/03/featured-image-horizontal.jpg">;

Super cool, right?

The next and final steps in the function is the setting of $html. You’ll see that if the $post_thumbnail_id isn’t set then it returns an empty string. From there the last line of code is:

return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );

So, it returns the HTML. Great. As you can see you can filter this.

New filter

Yes, we will use a filter because that is what all good developers like to use and should use.

add_filter( 'post_thumbnail_html', 'theme_slug_post_thumbnail', 10, 2 );
function theme_slug_post_thumbnail( $html, $size ) {
	// get featured image based on $post->ID
	$post_thumbnail_id = get_post_thumbnail_id( get_the_ID() );

	// set size
	$size = (string) apply_filters( 'post_thumbnail_size', 'my-theme-image' );

	//do your magic here
	if ( $post_thumbnail_id ) {
		if ( in_the_loop() ) {
			update_post_thumbnail_cache();
		}
		$html = wp_get_attachment_image( $post_thumbnail_id, $size );
	} else {
		$html = '<img class="featured-image" src="' . get_template_directory_uri() . '/img/custom-thumb.jpg" alt="Image">';
	}

	return '<div class="feature-image-wrapper">' . $html . '</div>';
}

As you can see it is a simplified filter because we aren’t changing every variable the function has to offer. You can, of course, explore more and create your own version. You will see that the one filter I kept was the post_thumbnail_size and that is because if a child theme is created, the child theme can change that with a simple filter.

JavaScript in PHP

Lately I’ve been seeing a few themes that like to include and devote an entire file to JavaScript. There is a reason I don’t like this. Biggest one is because it creates bad practices. Yes, I understand you want to pass some variables between the two languages but there are better ways. What’s super cool is that WordPress has this amazing function that theme, and plugin, developers can use.

Enter: wp_localize_script

It’s a great and amazing function. So the question is, when should it be used? A great example would be ( dare I say ) a slider. Yes, I know. The dreaded sliders. People love them but often have to make changes to files that could be lost when the theme updates.

Recently I was fiddling around with bxslider for fun. Neat little library and fun to use when you get the hang of it too. Really customizable with several options.

So, on to the code portion!

The first thing we do is to create our settings. I highly encourage the use of the customizer when possible so we will use it as our starting point. In this example, we create a setting for the slider’s autoplay setting. A simple setting that the user can turn on or off. The slider does have many more options that you can configure but we will stick to simplicity for this example.

$wp_customize->add_section( 'demo-slider', array(
	'title' => __( 'Slider options', 'dademo' ),
	'description' => __( 'Set the slider\'s options', 'dademo' ),
	'priority' => 130
	) );
$wp_customize->add_setting( 'demo-slider-auto', array(
	'default' => false,
	'sanitize_callback' => 'demo_checkbox'
	) );
$wp_customize->add_control( 'demo-slider-auto-setting', array(
	'label' => __( 'Autoplay', 'dademo' ),
	'section' => 'demo-slider',
	'settings' => 'demo-slider-auto',
	'type' => 'checkbox'
	) );

Please note, I have not included the demo_checkbox function. That is a simple function that checks for true or false which you can add yourself. From there we enqueue our scripts and possible styles if you are using or wanting any.

wp_enqueue_script( 'slider-js', get_template_directory_uri() . '/js/jquery.bxslider.min.js', array( 'jquery' ), null );
wp_enqueue_style( 'slider', get_template_directory_uri() . '/css/jquery.bxslider.css', null );
wp_enqueue_script( 'demo-js', get_template_directory_uri() . '/js/demo.js', array( 'slider-js','jquery' ), null );

Now, the only thing that is missing is to use wp_localize_script to create our JavaScript object. Yes, you read that right: JavaScript object.

In order to do that we first have to look at the function itself and see how it works. So let’s break it down a little, shall we?

Parameter, the first

The first parameter that we pass to it is the JavaScript file that we want to localize. The key thing to remember is that the script has to be already registered or enqueued, otherwise it will not create the object. For our example, we would use it after our slider is enqueued:

wp_enqueue_script( 'slider-js', get_template_directory_uri() . '/js/jquery.bxslider.min.js', array( 'jquery' ), null );
wp_enqueue_script( 'demo-js', get_template_directory_uri() . '/js/demo.js', array( 'slider-js','jquery' ), null );
wp_localize_script( 'slider-js', 'demoObj', $jsObj );

Our new object

Second, is the name of the JavaScript object that is created and used in our external JavaScript file or files. In this case it would be the demo-js file. Behind the scenes the function creates the variable and uses wp_json_encode to create our object. For this example the newly created object is called demoObj. It can be anything you want but ideally you want to prefix it so it won’t interfere with any other objects or even plugins. Yes, plugins.

Our user settings

Finally, we pass an associative array to the function. This is where your user settings will reside. In this example you can see we create a simple property of auto for our newly created JavaScript object. We then pass the array to wp_localize_script so it can be output in our header’s <head> element and used in our JavaScript files.

$slider = array();
$slider['auto'] = get_theme_mod( 'demo-slider-auto', false );
$jsObj = apply_filters( 'demo_slider', $slider);

wp_localize_script( 'slider-js', 'demoObj', $jsObj );

Yes, I like using filters when possible that way a child theme can override it. You don’t have to do it but it is something to think about. As I mentioned, behind the scenes, wp_localize_script will create the JavaSCript object and output it in the <head> section. The <head> output will look a little like the following snippet.

<script type='text/javascript'>
/* <![CDATA[ */
var demoObj = {"auto":""};
/* ]]> */
</script>

As you can see it creates a global variable that can be used in any JavaScript file. Since it is a simple example it created only one JavaScript property for the demoObj object.

What next?

Great! We have our newly created JavaScript object but how do we use it? What’s super neat is we can use it like any other JavaScript object when we get a property.

jQuery( document ).ready( function( $ ){
	$( '.gallery' ).bxSlider( {
		'auto': demoObj.auto,
		// alternatively use bracket notation
		// 'auto': demoObj['auto'],
	});
})

That’s great for settings, what happens when you are dealing with interaction or even text? A simple example would be adding a small dialogue when a user adds an item to a shopping cart. With wp_localize_script you can do it. Pippin has great example of this in his article.

So go explore and break things!