如何让WordPress JSON API返回分类法的slug或名称而非ID？

方法1：为目标接口添加额外字段 #

在主题functions.php或自定义插件中插入代码，给to_book类型的REST响应追加分类的名称或Slug字段：

add_action( 'rest_api_init', 'add_taxonomy_details_to_to_book' );
function add_taxonomy_details_to_to_book() {
    // 添加ba_language的Slug字段
    register_rest_field( 'to_book', 'ba_language_slug', array(
        'get_callback' => function( $post ) {
            $terms = wp_get_post_terms( $post['id'], 'ba_language' );
            return wp_list_pluck( $terms, 'slug' );
        },
        'schema' => array(
            'description' => 'ba_language分类的Slug',
            'type' => 'array',
            'items' => array( 'type' => 'string' )
        ),
    ) );

    // 添加ba_language的名称字段
    register_rest_field( 'to_book', 'ba_language_name', array(
        'get_callback' => function( $post ) {
            $terms = wp_get_post_terms( $post['id'], 'ba_language' );
            return wp_list_pluck( $terms, 'name' );
        },
        'schema' => array(
            'description' => 'ba_language分类的名称',
            'type' => 'array',
            'items' => array( 'type' => 'string' )
        ),
    ) );
}

方法2：直接替换原ID字段返回内容 #

如果希望彻底替换原ba_language字段的ID输出，可通过过滤器修改响应数据：

add_filter( 'rest_prepare_to_book', 'replace_taxonomy_id_with_details', 10, 3 );
function replace_taxonomy_id_with_details( $response, $post, $request ) {
    $terms = wp_get_post_terms( $post->ID, 'ba_language' );
    // 替换为Slug，若要名称则替换为wp_list_pluck($terms, 'name')
    $response->data['ba_language'] = wp_list_pluck( $terms, 'slug' );
    return $response;
}

方法3：创建自定义REST端点 #

若无法修改原接口代码，可新建自定义端点整合数据：

add_action( 'rest_api_init', 'custom_to_book_api_endpoint' );
function custom_to_book_api_endpoint() {
    register_rest_route( 'custom/v1', '/to_book', array(
        'methods' => 'GET',
        'callback' => 'fetch_to_book_with_taxonomy_details',
    ) );
}

function fetch_to_book_with_taxonomy_details( $request ) {
    $posts = get_posts( array(
        'post_type' => 'to_book',
        'posts_per_page' => -1,
    ) );
    $output = array();

    foreach ( $posts as $post ) {
        $base_data = get_post( $post->ID, ARRAY_A );
        $language_terms = wp_get_post_terms( $post->ID, 'ba_language' );
        $base_data['ba_language_slug'] = wp_list_pluck( $language_terms, 'slug' );
        $base_data['ba_language_name'] = wp_list_pluck( $language_terms, 'name' );
        $output[] = $base_data;
    }

    return rest_ensure_response( $output );
}

方法4：前端临时映射（无后端权限时用） #

如果无法修改后端，可在前端完成ID到名称/Slug的映射：

async function getToBookWithLanguageInfo() {
    const [toBookResp, langResp] = await Promise.all([
        fetch('/wp-json/wp/v2/to_book'),
        fetch('/wp-json/wp/v2/ba_language')
    ]);
    const toBookList = await toBookResp.json();
    const languageList = await langResp.json();
    
    const langMap = languageList.reduce((map, lang) => {
        map[lang.id] = { slug: lang.slug, name: lang.name };
        return map;
    }, {});

    return toBookList.map(item => {
        if (item.ba_language) {
            item.ba_language = item.ba_language.map(id => langMap[id].slug);
            // 若要名称则替换为 langMap[id].name
        }
        return item;
    });
}

内容的提问来源于stack exchange，提问作者omar al aufi