获取相邻文章
描述
译文
检索相邻的文章，可以是上一篇或下一篇。
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/* ———————————- function wphun_insert_query_vars( $vars ) { //新增参数 array_push($vars, ‘function_name’); return $vars; } |
原文
Retrieve adjacent post. Can either be next or previous post.
用法
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/* ———————————- <?php get_adjacent_post( $in_same_term, $excluded_terms, $previous, $taxonomy ) ?> |
参数
$in_same_term
(boolean) （可选）文章是否在同一分类。
默认值: false
$excluded_terms
(array or string) (可选) 排除分类的ID。
默认值: ”
$previous
(boolean) （可选）是否检索之前的文章。
默认值: true
$taxonomy
(string) (可选) 限定的分类名称，如果 $in_same_term 设置为 true。
默认值: ‘category’
返回值
如果成功，返回文章对象。
如果 global $post 没有设置，返回空值Null。
如果不存在符合条件的文章，返回空字符串。
示例
获取同分类下的上一篇文章。
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/* ———————————- <?php $prev_post = get_adjacent_post( true, ”, true, ‘taxonomy_slug’ ); ?> <?php if ( is_a( $prev_post, ‘WP_Post’ ) ) { ?> <a href=“<?php echo get_permalink( $prev_post->ID ); ?>“><?php echo get_the_title( $prev_post->ID ); ?></a> <?php } ?> |
获取同分类下的下一篇文章。
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/* ———————————- <?php $next_post = get_adjacent_post( true, ”, false, ‘taxonomy_slug’ ); ?> <?php if ( is_a( $next_post, ‘WP_Post’ ) ) { ?> <a href=“<?php echo get_permalink( $next_post->ID ); ?>“><?php echo get_the_title( $next_post->ID ); ?></a> <?php } ?> |
注意
使用 global: (object) $post
使用 global: (object) $wpdb
Filters过滤器
$adjacent 是 ‘previous’（上一篇） or ‘next’（下一篇）。
“get_{$adjacent}_post_join”:
$join, $in_same_cat, $excluded_categories
“get_{$adjacent}_post_where”:
$wpdb->prepare(“WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = ‘publish’ $posts_in_ex_cats_sql”, $current_post_date, $post->post_type), $in_same_cat, $excluded_categories
“get_{$adjacent}_post_sort”:
“ORDER BY p.post_date $order LIMIT 1”
历史
添加于 版本: 2.5.0
源文件
get_adjacent_post() 函数的代码位于 wp-includes/link-template.php.
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/* ———————————- function get_adjacent_post( $in_same_term = false, $excluded_terms = ”, $previous = true, $taxonomy = ‘category’ ) { global $wpdb; if ( ( ! $post = get_post() ) || ! taxonomy_exists( $taxonomy ) ) return null; $current_post_date = $post->post_date; $join = ”; $where = ”; if ( $in_same_term || ! empty( $excluded_terms ) ) { $join = ” INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id”; $where = $wpdb->prepare( “AND tt.taxonomy = %s”, $taxonomy ); if ( ! empty( $excluded_terms ) && ! is_array( $excluded_terms ) ) { // back-compat, $excluded_terms used to be $excluded_terms with IDs separated by ” and “ if ( false !== strpos( $excluded_terms, ‘ and ‘ ) ) { _deprecated_argument( __FUNCTION__, ‘3.3’, sprintf( __( ‘Use commas instead of %s to separate excluded terms.’ ), “‘and’” ) ); $excluded_terms = explode( ‘ and ‘, $excluded_terms ); } else { $excluded_terms = explode( ‘,’, $excluded_terms ); } $excluded_terms = array_map( ‘intval’, $excluded_terms ); } if ( $in_same_term ) { if ( ! is_object_in_taxonomy( $post->post_type, $taxonomy ) ) return ”; $term_array = wp_get_object_terms( $post->ID, $taxonomy, array( ‘fields’ => ‘ids’ ) ); // Remove any exclusions from the term array to include. $term_array = array_diff( $term_array, (array) $excluded_terms ); $term_array = array_map( ‘intval’, $term_array ); if ( ! $term_array || is_wp_error( $term_array ) ) return ”; $where .= ” AND tt.term_id IN (“ . implode( ‘,’, $term_array ) . “)”; } if ( ! empty( $excluded_terms ) ) { $where .= ” AND p.ID NOT IN ( SELECT tr.object_id FROM $wpdb->term_relationships tr LEFT JOIN $wpdb->term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id) WHERE tt.term_id IN (“ . implode( $excluded_terms, ‘,’ ) . ‘) )’; } } // ‘post_status’ clause depends on the current user. if ( is_user_logged_in() ) { $user_id = get_current_user_id(); $post_type_object = get_post_type_object( $post->post_type ); if ( empty( $post_type_object ) ) { $post_type_cap = $post->post_type; $read_private_cap = ‘read_private_’ . $post_type_cap . ‘s’; } else { $read_private_cap = $post_type_object->cap->read_private_posts; } /* * Results should include private posts belonging to the current user, or private posts where the $private_states = get_post_stati( array( ‘private’ => true ) ); $where .= ” AND ( p.post_status = ‘publish’”; foreach ( (array) $private_states as $state ) { if ( current_user_can( $read_private_cap ) ) { $where .= $wpdb->prepare( ” OR p.post_status = %s”, $state ); } else { $where .= $wpdb->prepare( ” OR (p.post_author = %d AND p.post_status = %s)”, $user_id, $state ); } } $where .= ” )”; } else { $where .= ” AND p.post_status = ‘publish’”; } $adjacent = $previous ? ‘previous’ : ‘next’; $op = $previous ? ‘<‘ :=“” ‘=””>’; $order = $previous ? ‘DESC’ : ‘ASC’; /** * Filter the JOIN clause in the SQL for an adjacent post query. $join = apply_filters( “get_{$adjacent}_post_join”, $join, $in_same_term, $excluded_terms ); /** * Filter the WHERE clause in the SQL for an adjacent post query. $where = apply_filters( “get_{$adjacent}_post_where”, $wpdb->prepare( “WHERE p.post_date $op %s AND p.post_type = %s $where”, $current_post_date, $post->post_type ), $in_same_term, $excluded_terms ); /** * Filter the ORDER BY clause in the SQL for an adjacent post query. $sort = apply_filters( “get_{$adjacent}_post_sort”, “ORDER BY p.post_date $order LIMIT 1” ); $query = “SELECT p.ID FROM $wpdb->posts AS p $join $where $sort”; $query_key = ‘adjacent_post_’ . md5( $query ); $result = wp_cache_get( $query_key, ‘counts’ ); if ( false !== $result ) { if ( $result ) $result = get_post( $result ); return $result; } $result = $wpdb->get_var( $query ); if ( null === $result ) $result = ”; wp_cache_set( $query_key, $result, ‘counts’ ); if ( $result ) $result = get_post( $result ); return $result; } </‘> |
相关
get_next_post(), get_previous_post()
原文：http://codex.wordpress.org/Function_Reference/get_adjacent_post
