功能:
get_option()函数是获取wp_options表中的一条数据,在获取数据前我们可以通过add_option()函数先来添加一条数据。
参数:
$show
(string) (必选) 获取选项的名称。 可用默认选项列表请参考此处:Option Reference。
默认: None
$default
(mixed) (可选) 默认的值,如果没有这条记录。
默认: false
返回值:
返回值可以是各种类型。
所在位置:
get_option() 函数包含在 wp-includes/option.php 中。
源码:
get_option()函数源码
/**
* Retrieves an option value based on an option name.
*
* If the option does not exist or does not have a value, then the return value
* will be false. This is useful to check whether you need to install an option
* and is commonly used during installation of plugin options and to test
* whether upgrading is required.
*
* If the option was serialized then it will be unserialized when it is returned.
*
* Any scalar values will be returned as strings. You may coerce the return type of
* a given option by registering an {@see 'option_$option'} filter callback.
*
* @since 1.5.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $option Name of option to retrieve. Expected to not be SQL-escaped.
* @param mixed $default Optional. Default value to return if the option does not exist.
* @return mixed Value set for the option.
*/
function get_option( $option, $default = false ) {
global $wpdb;
$option = trim( $option );
if ( empty( $option ) )
return false;
/**
* Filters the value of an existing option before it is retrieved.
*
* The dynamic portion of the hook name, `$option`, refers to the option name.
*
* Passing a truthy value to the filter will short-circuit retrieving
* the option value, returning the passed value instead.
*
* @since 1.5.0
* @since 4.4.0 The `$option` parameter was added.
*
* @param bool|mixed $pre_option Value to return instead of the option value.
* Default false to skip it.
* @param string $option Option name.
*/
$pre = apply_filters( "pre_option_{$option}", false, $option );
if ( false !== $pre )
return $pre;
if ( defined( 'WP_SETUP_CONFIG' ) )
return false;
// Distinguish between `false` as a default, and not passing one.
$passed_default = func_num_args() > 1;
if ( ! wp_installing() ) {
// prevent non-existent options from triggering multiple queries
$notoptions = wp_cache_get( 'notoptions', 'options' );
if ( isset( $notoptions[ $option ] ) ) {
/**
* Filters the default value for an option.
*
* The dynamic portion of the hook name, `$option`, refers to the option name.
*
* @since 3.4.0
* @since 4.4.0 The `$option` parameter was added.
* @since 4.7.0 The `$passed_default` parameter was added to distinguish between a `false` value and the default parameter value.
*
* @param mixed $default The default value to return if the option does not exist
* in the database.
* @param string $option Option name.
* @param bool $passed_default Was `get_option()` passed a default value?
*/
return apply_filters( "default_option_{$option}", $default, $option, $passed_default );
}
$alloptions = wp_load_alloptions();
if ( isset( $alloptions[$option] ) ) {
$value = $alloptions[$option];
} else {
$value = wp_cache_get( $option, 'options' );
if ( false === $value ) {
$row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", $option ) );
// Has to be get_row instead of get_var because of funkiness with 0, false, null values
if ( is_object( $row ) ) {
$value = $row->option_value;
wp_cache_add( $option, $value, 'options' );
} else { // option does not exist, so we must cache its non-existence
if ( ! is_array( $notoptions ) ) {
$notoptions = array();
}
$notoptions[$option] = true;
wp_cache_set( 'notoptions', $notoptions, 'options' );
/** This filter is documented in wp-includes/option.php */
return apply_filters( 'default_option_' . $option, $default, $option, $passed_default );
}
}
}
} else {
$suppress = $wpdb->suppress_errors();
$row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", $option ) );
$wpdb->suppress_errors( $suppress );
if ( is_object( $row ) ) {
$value = $row->option_value;
} else {
/** This filter is documented in wp-includes/option.php */
return apply_filters( 'default_option_' . $option, $default, $option, $passed_default );
}
}
// If home is not set use siteurl.
if ( 'home' == $option && '' == $value )
return get_option( 'siteurl' );
if ( in_array( $option, array('siteurl', 'home', 'category_base', 'tag_base') ) )
$value = untrailingslashit( $value );
/**
* Filters the value of an existing option.
*
* The dynamic portion of the hook name, `$option`, refers to the option name.
*
* @since 1.5.0 As 'option_' . $setting
* @since 3.0.0
* @since 4.4.0 The `$option` parameter was added.
*
* @param mixed $value Value of the option. If stored serialized, it will be
* unserialized prior to being returned.
* @param string $option Option name.
*/
return apply_filters( "option_{$option}", maybe_unserialize( $value ), $option );
}
示例:
相关函数:
add_option()
update_option()
delete_option()
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