50个WordPress过滤钩子（31-40）

<?php

add_filter( 'use_default_gallery_style', '__return_false' );

?>

<?php

add_filter( 'wp_get_attachment_url', 'wp_get_attachment_url_example' );

function wp_get_attachment_url_example( $url ) {
    $http  = site_url( false, 'http'  );
    $https = site_url( false, 'https' );

    if ( $_SERVER['HTTPS'] == 'on' )
        return str_replace( $http, $https, $url );
    else
        return $url;
}

// Example source: http://codex.wordpress.org/Plugin_API/Filter_Reference/wp_get_attachment_url

?>

<?php

add_filter( 'wp_mail_content_type', 'wp_mail_content_type_example' );

function wp_mail_content_type_example( $content_type ) {
    return 'text/html';
}

?>

<?php

add_filter( 'pre_comment_user_ip', 'pre_comment_user_ip_example' );

function pre_comment_user_ip_example() {
    $REMOTE_ADDR = $_SERVER['REMOTE_ADDR'];
    if ( !empty( $_SERVER['X_FORWARDED_FOR'] ) ) {
        $X_FORWARDED_FOR = explode( ',', $_SERVER['X_FORWARDED_FOR'] );
        if ( !empty( $X_FORWARDED_FOR ) )
            $REMOTE_ADDR = trim( $X_FORWARDED_FOR[0] );
    } elseif( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
        $HTTP_X_FORWARDED_FOR = explode( ',', $_SERVER['HTTP_X_FORWARDED_FOR'] );
        if ( !empty( $HTTP_X_FORWARDED_FOR ) )
            $REMOTE_ADDR = trim( $HTTP_X_FORWARDED_FOR[0] );
    }
    return preg_replace( '/[^0-9a-f:\., ]/si', '', $REMOTE_ADDR );
}

// Example source: https://codex.wordpress.org/Plugin_API/Filter_Reference/pre_comment_user_ip

?>

<?php

add_filter( 'wp_revisions_to_keep', 'wp_revisions_to_keep_example', 10, 2 );

function wp_revisions_to_keep_example( $num, $post ) {
    if ( 'event' == $post->post_type ) {
        return 0;
    }
    return $num;
}

// Example source: http://codex.wordpress.org/Plugin_API/Filter_Reference/wp_revisions_to_keep

?>

<?php

add_filter( 'img_caption_shortcode', 'img_caption_shortcode_example', 10, 3 );

function img_caption_shortcode_example( $empty, $attr, $content ) {
    $attr = shortcode_atts( array(
        'id'      => '',
        'align'   => 'alignnone',
        'width'   => '',
        'caption' => ''
    ), $attr );

    if ( 1 > (int) $attr['width'] || empty( $attr['caption'] ) ) {
        return '';
    }

    if ( $attr['id'] ) {
        $attr['id'] = 'id="' . esc_attr( $attr['id'] ) . '" ';
    }

    $figure_atts    = $attr['id']
                    . ' class="caption ' . esc_attr( $attr['align'] )
                    . '" ' . 'style="max-width: ' . ( 10 + (int) $attr['width'] ) . 'px;"';

    $output  = '<figure ' . $figure_atts . '>';
    $output .= do_shortcode( $content );
    $output .= '<figcaption>' . $attr['caption'] . '</figcaption>';
    $output .= '</figure>';

    return $output;

}

// Example source: http://codex.wordpress.org/Plugin_API/Filter_Reference/img_caption_shortcode

?>

<?php

add_filter( 'post_class', 'post_class_example' );

function post_class_example( $classes ) {
    global $wp_query;
    if ( 0 == $wp_query->current_post ) {
        $classes[] = 'first-post';
    }
    return $classes;
}

// Example source: http://www.billerickson.net/code/first-post-class/

?>

<?php

add_filter( 'attachment_fields_to_edit', 'attachment_fields_to_edit_example', 10, 2 );

function attachment_fields_to_edit_example( $form_fields, $post ) {
    $field_value = get_post_meta( $post->ID, 'license', true );
    $form_fields['license'] = array(
        'value' => $field_value ? $field_value : '',
        'label' => __( 'License' ),
        'helps' => __( 'Specify the license type used for this image' )
    );
    return $form_fields;
}

add_action( 'edit_attachment', 'save_new_attachment_field' );

function save_new_attachment_field( $attachment_id ) {
    $license = $_REQUEST['attachments'][$attachment_id]['license'];
    if ( isset( $license ) ) {
        update_post_meta( $attachment_id, 'license', $license );
    }
}

// Example source: http://codex.wordpress.org/Plugin_API/Filter_Reference/attachment_fields_to_edit

?>

<?php

add_filter( 'excerpt_length', 'excerpt_length_example' );

function excerpt_length_example( $words ) {
    return 15;
}

?>

<?php

add_filter( 'bulk_actions-edit-post', 'bulk_actions_edit_post_example' );

function bulk_actions_edit_post_example( $actions ) {
    unset( $actions['trash'] );
    return $actions;
}

?>