1<?php
2/**
3 * Server-side rendering of the `core/post-navigation-link` block.
4 *
5 * @package WordPress
6 */
7
8/**
9 * Renders the `core/post-navigation-link` block on the server.
10 *
11 * @since 5.9.0
12 *
13 * @param array $attributes Block attributes.
14 * @param string $content Block default content.
15 *
16 * @return string Returns the next or previous post link that is adjacent to the current post.
17 */
18function render_block_core_post_navigation_link( $attributes, $content ) {
19 if ( ! is_singular() ) {
20 return '';
21 }
22
23 // Get the navigation type to show the proper link. Available options are `next|previous`.
24 $navigation_type = isset( $attributes['type'] ) ? $attributes['type'] : 'next';
25 // Allow only `next` and `previous` in `$navigation_type`.
26 if ( ! in_array( $navigation_type, array( 'next', 'previous' ), true ) ) {
27 return '';
28 }
29 $classes = "post-navigation-link-$navigation_type";
30 if ( isset( $attributes['textAlign'] ) ) {
31 $classes .= " has-text-align-{$attributes['textAlign']}";
32 }
33 $wrapper_attributes = get_block_wrapper_attributes(
34 array(
35 'class' => $classes,
36 )
37 );
38 // Set default values.
39 $format = '%link';
40 $link = 'next' === $navigation_type ? _x( 'Next', 'label for next post link' ) : _x( 'Previous', 'label for previous post link' );
41 $label = '';
42
43 // Only use hardcoded values here, otherwise we need to add escaping where these values are used.
44 $arrow_map = array(
45 'none' => '',
46 'arrow' => array(
47 'next' => '→',
48 'previous' => '←',
49 ),
50 'chevron' => array(
51 'next' => '»',
52 'previous' => '«',
53 ),
54 );
55
56 // If a custom label is provided, make this a link.
57 // `$label` is used to prepend the provided label, if we want to show the page title as well.
58 if ( isset( $attributes['label'] ) && ! empty( $attributes['label'] ) ) {
59 $label = "{$attributes['label']}";
60 $link = $label;
61 }
62
63 // If we want to also show the page title, make the page title a link and prepend the label.
64 if ( isset( $attributes['showTitle'] ) && $attributes['showTitle'] ) {
65 /*
66 * If the label link option is not enabled but there is a custom label,
67 * display the custom label as text before the linked title.
68 */
69 if ( ! $attributes['linkLabel'] ) {
70 if ( $label ) {
71 $format = '<span class="post-navigation-link__label">' . wp_kses_post( $label ) . '</span> %link';
72 }
73 $link = '%title';
74 } elseif ( isset( $attributes['linkLabel'] ) && $attributes['linkLabel'] ) {
75 // If the label link option is enabled and there is a custom label, display it before the title.
76 if ( $label ) {
77 $link = '<span class="post-navigation-link__label">' . wp_kses_post( $label ) . '</span> <span class="post-navigation-link__title">%title</span>';
78 } else {
79 /*
80 * If the label link option is enabled and there is no custom label,
81 * add a colon between the label and the post title.
82 */
83 $label = 'next' === $navigation_type ? _x( 'Next:', 'label before the title of the next post' ) : _x( 'Previous:', 'label before the title of the previous post' );
84 $link = sprintf(
85 '<span class="post-navigation-link__label">%1$s</span> <span class="post-navigation-link__title">%2$s</span>',
86 wp_kses_post( $label ),
87 '%title'
88 );
89 }
90 }
91 }
92
93 // Display arrows.
94 if ( isset( $attributes['arrow'] ) && 'none' !== $attributes['arrow'] && isset( $arrow_map[ $attributes['arrow'] ] ) ) {
95 $arrow = $arrow_map[ $attributes['arrow'] ][ $navigation_type ];
96
97 if ( 'next' === $navigation_type ) {
98 $format = '%link<span class="wp-block-post-navigation-link__arrow-next is-arrow-' . $attributes['arrow'] . '" aria-hidden="true">' . $arrow . '</span>';
99 } else {
100 $format = '<span class="wp-block-post-navigation-link__arrow-previous is-arrow-' . $attributes['arrow'] . '" aria-hidden="true">' . $arrow . '</span>%link';
101 }
102 }
103
104 /*
105 * The dynamic portion of the function name, `$navigation_type`,
106 * Refers to the type of adjacency, 'next' or 'previous'.
107 *
108 * @see https://developer.wordpress.org/reference/functions/get_previous_post_link/
109 * @see https://developer.wordpress.org/reference/functions/get_next_post_link/
110 */
111 $get_link_function = "get_{$navigation_type}_post_link";
112
113 if ( ! empty( $attributes['taxonomy'] ) ) {
114 $content = $get_link_function( $format, $link, true, '', $attributes['taxonomy'] );
115 } else {
116 $content = $get_link_function( $format, $link );
117 }
118
119 return sprintf(
120 '<div %1$s>%2$s</div>',
121 $wrapper_attributes,
122 $content
123 );
124}
125
126/**
127 * Registers the `core/post-navigation-link` block on the server.
128 *
129 * @since 5.9.0
130 */
131function register_block_core_post_navigation_link() {
132 register_block_type_from_metadata(
133 __DIR__ . '/post-navigation-link',
134 array(
135 'render_callback' => 'render_block_core_post_navigation_link',
136 )
137 );
138}
139add_action( 'init', 'register_block_core_post_navigation_link' );
140