如何使用流式排版实现WordPress自由缩放字体
dbdelta ( $queries = '', $execute = true )
dbdelta: 这个函数用来更新数据库模式，以符合一个给定的SQL语句的结构。它被WordPress在插件和主题安装和更新时使用，以确保数据库模式与代码相匹配。
根据指定的SQL语句来修改数据库。
对于创建新的表和更新现有的表到一个新的结构很有用。
function dbDelta( $queries = '', $execute = true ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.FunctionNameInvalid
global $wpdb;
if ( in_array( $queries, array( '', 'all', 'blog', 'global', 'ms_global' ), true ) ) {
$queries = wp_get_db_schema( $queries );
}
// Separate individual queries into an array.
if ( ! is_array( $queries ) ) {
$queries = explode( ';', $queries );
$queries = array_filter( $queries );
}
/**
* Filters the dbDelta SQL queries.
*
* @since 3.3.0
*
* @param string[] $queries An array of dbDelta SQL queries.
*/
$queries = apply_filters( 'dbdelta_queries', $queries );
$cqueries = array(); // Creation queries.
$iqueries = array(); // Insertion queries.
$for_update = array();
// Create a tablename index for an array ($cqueries) of queries.
foreach ( $queries as $qry ) {
if ( preg_match( '|CREATE TABLE ([^ ]*)|', $qry, $matches ) ) {
$cqueries[ trim( $matches[1], '`' ) ] = $qry;
$for_update[ $matches[1] ] = 'Created table ' . $matches[1];
} elseif ( preg_match( '|CREATE DATABASE ([^ ]*)|', $qry, $matches ) ) {
array_unshift( $cqueries, $qry );
} elseif ( preg_match( '|INSERT INTO ([^ ]*)|', $qry, $matches ) ) {
$iqueries[] = $qry;
} elseif ( preg_match( '|UPDATE ([^ ]*)|', $qry, $matches ) ) {
$iqueries[] = $qry;
} else {
// Unrecognized query type.
}
}
/**
* Filters the dbDelta SQL queries for creating tables and/or databases.
*
* Queries filterable via this hook contain "CREATE TABLE" or "CREATE DATABASE".
*
* @since 3.3.0
*
* @param string[] $cqueries An array of dbDelta create SQL queries.
*/
$cqueries = apply_filters( 'dbdelta_create_queries', $cqueries );
/**
* Filters the dbDelta SQL queries for inserting or updating.
*
* Queries filterable via this hook contain "INSERT INTO" or "UPDATE".
*
* @since 3.3.0
*
* @param string[] $iqueries An array of dbDelta insert or update SQL queries.
*/
$iqueries = apply_filters( 'dbdelta_insert_queries', $iqueries );
$text_fields = array( 'tinytext', 'text', 'mediumtext', 'longtext' );
$blob_fields = array( 'tinyblob', 'blob', 'mediumblob', 'longblob' );
$int_fields = array( 'tinyint', 'smallint', 'mediumint', 'int', 'integer', 'bigint' );
$global_tables = $wpdb->tables( 'global' );
$db_version = $wpdb->db_version();
$db_server_info = $wpdb->db_server_info();
foreach ( $cqueries as $table => $qry ) {
// Upgrade global tables only for the main site. Don't upgrade at all if conditions are not optimal.
if ( in_array( $table, $global_tables, true ) && ! wp_should_upgrade_global_tables() ) {
unset( $cqueries[ $table ], $for_update[ $table ] );
continue;
}
// Fetch the table column structure from the database.
$suppress = $wpdb->suppress_errors();
$tablefields = $wpdb->get_results( "DESCRIBE {$table};" );
$wpdb->suppress_errors( $suppress );
if ( ! $tablefields ) {
continue;
}
// Clear the field and index arrays.
$cfields = array();
$indices = array();
$indices_without_subparts = array();
// Get all of the field names in the query from between the parentheses.
preg_match( '|((.*))|ms', $qry, $match2 );
$qryline = trim( $match2[1] );
// Separate field lines into an array.
$flds = explode( "n", $qryline );
// For every field line specified in the query.
foreach ( $flds as $fld ) {
$fld = trim( $fld, " tnrx0B," ); // Default trim characters, plus ','.
// Extract the field name.
preg_match( '|^([^ ]*)|', $fld, $fvals );
$fieldname = trim( $fvals[1], '`' );
$fieldname_lowercased = strtolower( $fieldname );
// Verify the found field name.
$validfield = true;
switch ( $fieldname_lowercased ) {
case '':
case 'primary':
case 'index':
case 'fulltext':
case 'unique':
case 'key':
case 'spatial':
$validfield = false;
/*
* Normalize the index definition.
*
* This is done so the definition can be compared against the result of a
* `SHOW INDEX FROM $table_name` query which returns the current table
* index information.
*/
// Extract type, name and columns from the definition.
// phpcs:disable Squiz.Strings.ConcatenationSpacing.PaddingFound -- don't remove regex indentation
preg_match(
'/^'
. '(?P<index_type>' // 1) Type of the index.
. 'PRIMARYs+KEY|(?:UNIQUE|FULLTEXT|SPATIAL)s+(?:KEY|INDEX)|KEY|INDEX'
. ')'
. 's+' // Followed by at least one white space character.
. '(?:' // Name of the index. Optional if type is PRIMARY KEY.
. '`?' // Name can be escaped with a backtick.
. '(?P<index_name>' // 2) Name of the index.
. '(?:[0-9a-zA-Z$_-]|[xC2-xDF][x80-xBF])+'
. ')'
. '`?' // Name can be escaped with a backtick.
. 's+' // Followed by at least one white space character.
. ')*'
. '(' // Opening bracket for the columns.
. '(?P<index_columns>'
. '.+?' // 3) Column names, index prefixes, and orders.
. ')'
. ')' // Closing bracket for the columns.
. '$/im',
$fld,
$index_matches
);
// phpcs:enable
// Uppercase the index type and normalize space characters.
$index_type = strtoupper( preg_replace( '/s+/', ' ', trim( $index_matches['index_type'] ) ) );
// 'INDEX' is a synonym for 'KEY', standardize on 'KEY'.
$index_type = str_replace( 'INDEX', 'KEY', $index_type );
// Escape the index name with backticks. An index for a primary key has no name.
$index_name = ( 'PRIMARY KEY' === $index_type ) ? '' : '`' . strtolower( $index_matches['index_name'] ) . '`';
// Parse the columns. Multiple columns are separated by a comma.
$index_columns = array_map( 'trim', explode( ',', $index_matches['index_columns'] ) );
$index_columns_without_subparts = $index_columns;
// Normalize columns.
foreach ( $index_columns as $id => &$index_column ) {
// Extract column name and number of indexed characters (sub_part).
// phpcs:disable Squiz.Strings.ConcatenationSpacing.PaddingFound -- don't remove regex indentation
preg_match(
'/'
. '`?' // Name can be escaped with a backtick.
. '(?P<column_name>' // 1) Name of the column.
. '(?:[0-9a-zA-Z$_-]|[xC2-xDF][x80-xBF])+'
. ')'
. '`?' // Name can be escaped with a backtick.
. '(?:' // Optional sub part.
. 's*' // Optional white space character between name and opening bracket.
. '(' // Opening bracket for the sub part.
. 's*' // Optional white space character after opening bracket.
. '(?P<sub_part>'
. 'd+' // 2) Number of indexed characters.
. ')'
. 's*' // Optional white space character before closing bracket.
. ')' // Closing bracket for the sub part.
. ')?'
. '/',
$index_column,
$index_column_matches
);
// phpcs:enable
// Escape the column name with backticks.
$index_column = '`' . $index_column_matches['column_name'] . '`';
// We don't need to add the subpart to $index_columns_without_subparts
$index_columns_without_subparts[ $id ] = $index_column;
// Append the optional sup part with the number of indexed characters.
if ( isset( $index_column_matches['sub_part'] ) ) {
$index_column .= '(' . $index_column_matches['sub_part'] . ')';
}
}
// Build the normalized index definition and add it to the list of indices.
$indices[] = "{$index_type} {$index_name} (" . implode( ',', $index_columns ) . ')';
$indices_without_subparts[] = "{$index_type} {$index_name} (" . implode( ',', $index_columns_without_subparts ) . ')';
// Destroy no longer needed variables.
unset( $index_column, $index_column_matches, $index_matches, $index_type, $index_name, $index_columns, $index_columns_without_subparts );
break;
}
// If it's a valid field, add it to the field array.
if ( $validfield ) {
$cfields[ $fieldname_lowercased ] = $fld;
}
}
// For every field in the table.
foreach ( $tablefields as $tablefield ) {
$tablefield_field_lowercased = strtolower( $tablefield->Field );
$tablefield_type_lowercased = strtolower( $tablefield->Type );
$tablefield_type_without_parentheses = preg_replace(
'/'
. '(.+)' // Field type, e.g. `int`.
. '(d*)' // Display width.
. '(.*)' // Optional attributes, e.g. `unsigned`.
. '/',
'$1$2',
$tablefield_type_lowercased
);
// Get the type without attributes, e.g. `int`.
$tablefield_type_base = strtok( $tablefield_type_without_parentheses, ' ' );
// If the table field exists in the field array...
if ( array_key_exists( $tablefield_field_lowercased, $cfields ) ) {
// Get the field type from the query.
preg_match( '|`?' . $tablefield->Field . '`? ([^ ]*( unsigned)?)|i', $cfields[ $tablefield_field_lowercased ], $matches );
$fieldtype = $matches[1];
$fieldtype_lowercased = strtolower( $fieldtype );
$fieldtype_without_parentheses = preg_replace(
'/'
. '(.+)' // Field type, e.g. `int`.
. '(d*)' // Display width.
. '(.*)' // Optional attributes, e.g. `unsigned`.
. '/',
'$1$2',
$fieldtype_lowercased
);
// Get the type without attributes, e.g. `int`.
$fieldtype_base = strtok( $fieldtype_without_parentheses, ' ' );
// Is actual field type different from the field type in query?
if ( $tablefield->Type != $fieldtype ) {
$do_change = true;
if ( in_array( $fieldtype_lowercased, $text_fields, true ) && in_array( $tablefield_type_lowercased, $text_fields, true ) ) {
if ( array_search( $fieldtype_lowercased, $text_fields, true ) < array_search( $tablefield_type_lowercased, $text_fields, true ) ) {
$do_change = false;
}
}
if ( in_array( $fieldtype_lowercased, $blob_fields, true ) && in_array( $tablefield_type_lowercased, $blob_fields, true ) ) {
if ( array_search( $fieldtype_lowercased, $blob_fields, true ) < array_search( $tablefield_type_lowercased, $blob_fields, true ) ) {
$do_change = false;
}
}
if ( in_array( $fieldtype_base, $int_fields, true ) && in_array( $tablefield_type_base, $int_fields, true )
&& $fieldtype_without_parentheses === $tablefield_type_without_parentheses
) {
/*
* MySQL 8.0.17 or later does not support display width for integer data types,
* so if display width is the only difference, it can be safely ignored.
* Note: This is specific to MySQL and does not affect MariaDB.
*/
if ( version_compare( $db_version, '8.0.17', '>=' )
&& ! str_contains( $db_server_info, 'MariaDB' )
) {
$do_change = false;
}
}
if ( $do_change ) {
// Add a query to change the column type.
$cqueries[] = "ALTER TABLE {$table} CHANGE COLUMN `{$tablefield->Field}` " . $cfields[ $tablefield_field_lowercased ];
$for_update[ $table . '.' . $tablefield->Field ] = "Changed type of {$table}.{$tablefield->Field} from {$tablefield->Type} to {$fieldtype}";
}
}
// Get the default value from the array.
if ( preg_match( "| DEFAULT '(.*?)'|i", $cfields[ $tablefield_field_lowercased ], $matches ) ) {
$default_value = $matches[1];
if ( $tablefield->Default != $default_value ) {
// Add a query to change the column's default value
$cqueries[] = "ALTER TABLE {$table} ALTER COLUMN `{$tablefield->Field}` SET DEFAULT '{$default_value}'";
$for_update[ $table . '.' . $tablefield->Field ] = "Changed default value of {$table}.{$tablefield->Field} from {$tablefield->Default} to {$default_value}";
}
}
// Remove the field from the array (so it's not added).
unset( $cfields[ $tablefield_field_lowercased ] );
} else {
// This field exists in the table, but not in the creation queries?
}
}
// For every remaining field specified for the table.
foreach ( $cfields as $fieldname => $fielddef ) {
// Push a query line into $cqueries that adds the field to that table.
$cqueries[] = "ALTER TABLE {$table} ADD COLUMN $fielddef";
$for_update[ $table . '.' . $fieldname ] = 'Added column ' . $table . '.' . $fieldname;
}
// Index stuff goes here. Fetch the table index structure from the database.
$tableindices = $wpdb->get_results( "SHOW INDEX FROM {$table};" );
if ( $tableindices ) {
// Clear the index array.
$index_ary = array();
// For every index in the table.
foreach ( $tableindices as $tableindex ) {
$keyname = strtolower( $tableindex->Key_name );
// Add the index to the index data array.
$index_ary[ $keyname ]['columns'][] = array(
'fieldname' => $tableindex->Column_name,
'subpart' => $tableindex->Sub_part,
);
$index_ary[ $keyname ]['unique'] = ( 0 == $tableindex->Non_unique ) ? true : false;
$index_ary[ $keyname ]['index_type'] = $tableindex->Index_type;
}
// For each actual index in the index array.
foreach ( $index_ary as $index_name => $index_data ) {
// Build a create string to compare to the query.
$index_string = '';
if ( 'primary' === $index_name ) {
$index_string .= 'PRIMARY ';
} elseif ( $index_data['unique'] ) {
$index_string .= 'UNIQUE ';
}
if ( 'FULLTEXT' === strtoupper( $index_data['index_type'] ) ) {
$index_string .= 'FULLTEXT ';
}
if ( 'SPATIAL' === strtoupper( $index_data['index_type'] ) ) {
$index_string .= 'SPATIAL ';
}
$index_string .= 'KEY ';
if ( 'primary' !== $index_name ) {
$index_string .= '`' . $index_name . '`';
}
$index_columns = '';
// For each column in the index.
foreach ( $index_data['columns'] as $column_data ) {
if ( '' !== $index_columns ) {
$index_columns .= ',';
}
// Add the field to the column list string.
$index_columns .= '`' . $column_data['fieldname'] . '`';
}
// Add the column list to the index create string.
$index_string .= " ($index_columns)";
// Check if the index definition exists, ignoring subparts.
$aindex = array_search( $index_string, $indices_without_subparts, true );
if ( false !== $aindex ) {
// If the index already exists (even with different subparts), we don't need to create it.
unset( $indices_without_subparts[ $aindex ] );
unset( $indices[ $aindex ] );
}
}
}
// For every remaining index specified for the table.
foreach ( (array) $indices as $index ) {
// Push a query line into $cqueries that adds the index to that table.
$cqueries[] = "ALTER TABLE {$table} ADD $index";
$for_update[] = 'Added index ' . $table . ' ' . $index;
}
// Remove the original table creation query from processing.
unset( $cqueries[ $table ], $for_update[ $table ] );
}
$allqueries = array_merge( $cqueries, $iqueries );
if ( $execute ) {
foreach ( $allqueries as $query ) {
$wpdb->query( $query );
}
}
return $for_update;
}
要使用` get_users `函数获取所有用户列表，可以按照以下步骤进行：
1. 使用` get_users `函数调用获取用户列表：
$users = get_users();
2. 您可以按需使用参数来过滤结果。例如，您可以通过角色、用户ID、用户登录名等过滤用户列表。以下是一个根据用户角色为过滤条件的示例：
$users = get_users( array(
'role' => 'subscriber' // 将角色名称替换为您要过滤的角色
) );
在上述示例中，将` role `参数设置为所需的角色名称来过滤用户列表。
3. 您可以使用循环遍历获取的用户列表，并访问每个用户的属性。例如，以下示例将显示每个用户的用户名和电子邮件地址：
foreach( $users as $user ) {
echo '用户名：' . $user->user_login . ', 电子邮件：' . $user->user_email . ;
}
在上述示例中，通过` $user->user_login `和` $user->user_email `访问每个用户的用户名和电子邮件地址。
请注意，` get_users `函数默认返回所有用户，并可以根据需要使用更多参数进行过滤。您可以参阅WordPress官方文档中的` get_users `函数文档，了解更多可用参数和用法示例。
总结起来，使用` get_users `函数获取所有用户列表的步骤是：
get_users `函数获取用户列表。在WordPress中，可以使用WP_PLUGIN_DIR和WP_PLUGIN_URL常量来定义插件的目录路径和URL。
1. `WP_PLUGIN_DIR`：这是一个常量，用于定义插件的目录路径（文件系统路径）。您可以使用以下代码在插件文件中访问该常量：
$plugin_dir = WP_PLUGIN_DIR . '/your-plugin-folder/';
在上述代码中，将"your-plugin-folder"替换为您插件的实际文件夹名称。使用该常量，您可以获取插件文件的完整路径。
2. `WP_PLUGIN_URL`：这是一个常量，用于定义插件的URL（用于在网页上访问插件文件）。以下是一个使用该常量的示例：
$plugin_url = WP_PLUGIN_URL . '/your-plugin-folder/';
同样，请将"your-plugin-folder"替换为您插件的实际文件夹名称。使用该常量，您可以获取插件在网页上的完整URL。
请注意，`WP_PLUGIN_DIR`和`WP_PLUGIN_URL`常量在WordPress版本2.6之后引入。从WordPress 5.5版本开始，这两个常量被标记为过时（deprecated），因为WordPress更倾向于使用新的插件文件结构。如果您正在开发新插件，建议使用新的插件文件结构和相关函数。
在新的插件文件结构中，可以使用以下函数来获取插件的目录路径和URL：
- `plugin_dir_path()`：获取插件目录路径。
- `plugin_dir_url()`：获取插件URL。
这些函数会自动将插件的版本、多站点和SSL等考虑因素纳入计算。
总结起来，使用`WP_PLUGIN_DIR`和`WP_PLUGIN_URL`常量定义插件的目录和URL的方法是：
$plugin_dir = WP_PLUGIN_DIR . '/your-plugin-folder/'; $plugin_url = WP_PLUGIN_URL . '/your-plugin-folder/';
但请注意，这两个常量已被标记为过时，建议使用新的插件文件结构和相关函数来获取插件的路径和URL。
使用PHP在WordPress中添加自定义功能可以通过以下方式实现：
下面是一个实操示例。
要在WordPress中添加自定义功能，可以按照以下步骤使用PHP编写并添加自定义功能：
// 添加自定义功能示例
// 1. 创建自定义短代码
function custom_shortcode() {
return '这是我的自定义短代码内容';
}
add_shortcode('custom', 'custom_shortcode');
// 2. 自定义小工具
function custom_widget() {
echo '这是我的自定义小工具内容';
}
register_widget('custom_widget');
// 3. 自定义菜单
function custom_menu() {
register_nav_menu('custom-menu', '自定义菜单');
}
add_action('after_setup_theme', 'custom_menu');
// 4. 自定义页面模板
function custom_page_template() {
/* Template Name: 自定义模板 */
// 自定义模板的内容和样式
}
请注意，修改主题文件可以在主题更新时丢失，因此建议在进行任何更改之前备份functions.php文件。此外，为避免不必要的错误和冲突，建议在添加自定义功能前先了解WordPress开发文档和最佳实践，以确保正确、安全地实现所需的自定义功能。
使用 do_action 函数可以触发一个钩子函数。do_action 函数的参数与要触发的钩子函数的参数相同。
例如，触发save_post钩子函数的代码如下：
do_action( 'save_post', $post_ID, $post );
这里，$post_ID 和 $post 是传递给钩子函数的参数。
使用 wp_get_current_user 获取当前登录用户的信息：
$current_user = wp_get_current_user(); // 获取当前用户的ID $user_id = $current_user->ID; // 获取当前用户的用户名 $user_login = $current_user->user_login; // 获取当前用户的邮箱 $user_email = $current_user->user_email; // 获取当前用户的显示名称 $display_name = $current_user->display_name;
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