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add_meta()

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概述

add_meta() 函数用于为指定文章添加元数据，数据来源于 $_POST 超全局变量，通常用于处理“自定义字段”表单提交。它根据输入选择元键，并调用 add_post_meta() 实现存储。

关键要点

  • 参数 $post_id 为整数类型，必需，指定文章 ID
  • 返回值类型为 int|bool，成功时返回元 ID，失败返回 false
  • 元数据从 $_POST['metakeyselect']、$_POST['metakeyinput'] 和 $_POST['metavalue'] 获取
  • 元键优先使用输入字段（metakeyinput），若两者都存在则忽略选择字段（metakeyselect）
  • 函数会检查元键是否受保护（is_protected_meta）和用户权限（current_user_can）
  • 内部使用 wp_unslash 和 wp_slash 处理字符串转义

代码示例

add_meta( $post_ID );

注意事项

除非开发了使用自定义字段小部件的自定义文章表单，否则很少直接使用此函数。

📄 原文内容

Adds post meta data defined in the $_POST superglobal for a post with given ID.

Parameters

$post_idintrequired

Return

int|bool

More Information

  • The information used is POSTed from the “Custom Fields” form on the Edit Post Administration screen.
  • Data used for the added metadata is taken from $_POST['metakeyselect'], $_POST['metakeyinput'], $_POST['metavalue']. Either the select or input fields are used for the meta key. If both are present, input field is used.

Source

function add_meta( $post_id ) {
	$post_id = (int) $post_id;

	$metakeyselect = isset( $_POST['metakeyselect'] ) ? wp_unslash( trim( $_POST['metakeyselect'] ) ) : '';
	$metakeyinput  = isset( $_POST['metakeyinput'] ) ? wp_unslash( trim( $_POST['metakeyinput'] ) ) : '';
	$metavalue     = isset( $_POST['metavalue'] ) ? $_POST['metavalue'] : '';
	if ( is_string( $metavalue ) ) {
		$metavalue = trim( $metavalue );
	}

	if ( ( ( '#NONE#' !== $metakeyselect ) && ! empty( $metakeyselect ) ) || ! empty( $metakeyinput ) ) {
		/*
		 * We have a key/value pair. If both the select and the input
		 * for the key have data, the input takes precedence.
		 */
		if ( '#NONE#' !== $metakeyselect ) {
			$metakey = $metakeyselect;
		}

		if ( $metakeyinput ) {
			$metakey = $metakeyinput; // Default.
		}

		if ( is_protected_meta( $metakey, 'post' ) || ! current_user_can( 'add_post_meta', $post_id, $metakey ) ) {
			return false;
		}

		$metakey = wp_slash( $metakey );

		return add_post_meta( $post_id, $metakey, $metavalue );
	}

	return false;
}

View all references View on Trac View on GitHub

Uses Description
add_post_meta()wp-includes/post.php

Adds a meta field to the given post.
is_protected_meta()wp-includes/meta.php

Determines whether a meta key is considered protected.
current_user_can()wp-includes/capabilities.php

Returns whether the current user has the specified capability.
wp_unslash()wp-includes/formatting.php

Removes slashes from a string or recursively removes slashes from strings within an array.
wp_slash()wp-includes/formatting.php

Adds slashes to a string or recursively adds slashes to strings within an array.

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Used by Description
wp_write_post()wp-admin/includes/post.php

Creates a new post from the “Write Post” form using $_POST information.
edit_post()wp-admin/includes/post.php

Updates an existing post with values provided in $_POST.
wp_ajax_add_meta()wp-admin/includes/ajax-actions.php

Handles adding meta via AJAX.

Changelog

Version Description
1.2.0 Introduced.

User Contributed Notes