Little-known functions in WordPress

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Has it ever happened that during parsing code-party plugin or theme you found quite useful standard function, which did not know before? At such moments, any developer feels a sense of worthlessness, remembering he reinvented the wheel in previous projects.

In order to reduce the amount of frustration, I decided to describe a few little-known but very useful features:

make_clickable
Find in the text links and make them clickable.
Example:

$string = "This is a long text that contains some links like https://www.wordpress.org and https://www.wordpress.com .";
echo make_clickable( $string ); 

popuplinks
Adds  target='_ blank' rel='external' to all the links in the text.
Example:

$string = "This is a long text that contains some links like <a href='https://www.wordpress.org'>https://www.wordpress.org</a> and <a href='https://www.wordpress.com'>https://www.wordpress.com</a> .";
echo popuplinks( $string ); 

wp_list_pluck
Takes out certain fields from the collection.
Example:

$posts = get_posts();
$ids = wp_list_pluck( $posts, 'ID' ); // [1, 2, 3, ...]

antispambot
Converts email addresses to symbols HTML for protection from spambots.
Example:

$email = 'ex*****@em***.com';
echo '<a href="mailto:' . antispambot( $email ) . '">' . antispambot( $email ) . '</a>';

checked / selected
Adds an attribute checked (selected) if the first argument is equal to the second.
Example:

<input type="checkbox" name="remember" value="1" <?php checked( $remember ) ?> />
<select name="options">
    <option value="1" <?php selected( $options, 1 ); ?>>1</option>
    <option value="2" <?php selected( $options, 2 ); ?>>2</option>
    <option value="3" <?php selected( $options, 3 ); ?>>3</option>
</select>

human_time_diff
Represents the difference in time in human-readable form.
Example:

$published = get_the_time( 'U' );
echo human_time_diff( $published ); // 2 days

wp_send_json_success / wp_send_json_error
Displays data in a JSON format for Ajax requests.
Example:

if( $success ) {
    $result = array(
        'message'	=> 'Saved',
        'ID'		=> 1
    );
    wp_send_json_success( $result ); // { "success": true, "data": { "message": "Saved", "ID": 1 } }
}
else {
    wp_send_json_error(); // { "success": false }
}

wp_remote_get / wp_remote_post
Receives data from a third-party web resource.
Example:

$response = wp_remote_get( "https://api.twitter.com/1.1/search/tweets.json?q=%23WordPress", array( 'timeout' => 10 ) );
$tweets = wp_remote_retrieve_body( $response );

wp_is_mobile
Specifies the user’s device.
Example:

if ( wp_is_mobile() ) {
    get_footer( 'mobile' );
}
else {
    get_footer();
}

wp_oembed_get
Converts a link to a media resource in the code of the player.
Example:

$youtube_url = 'https://www.youtube.com/watch?v=Lcvh0DgytH8';
$embed_code = wp_oembed_get( $youtube_url, array( 'width' => 800 ) );

wp_tempnam
Creates a temporary file with a unique name.
Example:

wp_tempnam( 'cache.log', get_temp_dir() );

zeroise
Complements the number with zeros to the specified length.
Example:

$tickets_count = 8;
echo zeroise( $tickets_count, 3 ); // 008

capital_P_dangit
Corrects common errors in brand name WordPress.
Example:

$string = "I Love WordPress";
echo capital_P_dangit( $string ); // I Love WordPress

get_num_queries
Shows the total number of SQL-queries to the database page.
Example:

<!-- Number of queries: <?php echo get_num_queries(); ?> -->

wp_text_diff
Finds the differences in the text and displays them in a convenient form for comparison.
Example:

$left_string = 'This is the original string';
$right_string = 'This is the revised string';
echo wp_text_diff( $left_string, $right_string );

submit_button
Generates code for the button.
Example:

<?php submit_button( __( 'Save Changes' ) ); ?>

enjoy 🙂

This text is a translation of article “Малоизвестные функции в WordPress” by Pingbull published on habrahabr.ru.

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