wpdb::prepare() │ public │ WP 2.3.0
Prepares a SQL query for safe execution.
Uses sprintf()-like syntax. The following placeholders can be used in the query string:
- %d (integer)
- %f (float)
- %s (string)
All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
Note: There is one exception to the above: for compatibility with old behavior, numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes added by this function, so should be passed with appropriate quotes around them.
Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards (for example, to use in LIKE syntax) must be passed via a substitution argument containing the complete LIKE string, these cannot be inserted directly in the query string. Also see wpdb::esc_like().
Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination of the two is not supported.
Examples:
$wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s", array( 'foo', 1337, '%bar' ) );
$wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
{} It's a method of the class: wpdb{}
No Hooks.
Return
String|null
. Sanitized query string, if there is a query to prepare.
Usage
global $wpdb;
$wpdb->prepare( $query, ...$args );
- $query(string) (required)
- Query statement with sprintf()-like placeholders.
- ...$args(mixed) (required)
- Further variables to substitute into the query's placeholders if being called with individual arguments.
Changelog
Since 2.3.0 |
Introduced. |
Since 5.3.0 |
Formalized the existing and already documented ...$args parameter by updating the function signature. The second parameter was changed from $args to ...$args. |
Code of wpdb::prepare() wpdb::prepare
WP 5.9.3
public function prepare( $query, ...$args ) {
if ( is_null( $query ) ) {
return;
}
// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
if ( strpos( $query, '%' ) === false ) {
wp_load_translations_early();
_doing_it_wrong(
'wpdb::prepare',
sprintf(
/* translators: %s: wpdb::prepare() */
__( 'The query argument of %s must have a placeholder.' ),
'wpdb::prepare()'
),
'3.9.0'
);
}
// If args were passed as an array (as in vsprintf), move them up.
$passed_as_array = false;
if ( isset( $args[0] ) && is_array( $args[0] ) && 1 === count( $args ) ) {
$passed_as_array = true;
$args = $args[0];
}
foreach ( $args as $arg ) {
if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
wp_load_translations_early();
_doing_it_wrong(
'wpdb::prepare',
sprintf(
/* translators: %s: Value type. */
__( 'Unsupported value type (%s).' ),
gettype( $arg )
),
'4.8.2'
);
}
}
/*
* Specify the formatting allowed in a placeholder. The following are allowed:
*
* - Sign specifier. eg, $+d
* - Numbered placeholders. eg, %1$s
* - Padding specifier, including custom padding characters. eg, %05s, %'#5s
* - Alignment specifier. eg, %05-s
* - Precision specifier. eg, %.2f
*/
$allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
/*
* If a %s placeholder already has quotes around it, removing the existing quotes and re-inserting them
* ensures the quotes are consistent.
*
* For backward compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
* used in the middle of longer strings, or as table name placeholders.
*/
$query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
$query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
$query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.
$query = preg_replace( "/(?<!%)(%($allowed_format)?f)/", '%\\2F', $query ); // Force floats to be locale-unaware.
$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
// Count the number of valid placeholders in the query.
$placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
$args_count = count( $args );
if ( $args_count !== $placeholders ) {
if ( 1 === $placeholders && $passed_as_array ) {
// If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
wp_load_translations_early();
_doing_it_wrong(
'wpdb::prepare',
__( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ),
'4.9.0'
);
return;
} else {
/*
* If we don't have the right number of placeholders, but they were passed as individual arguments,
* or we were expecting multiple arguments in an array, throw a warning.
*/
wp_load_translations_early();
_doing_it_wrong(
'wpdb::prepare',
sprintf(
/* translators: 1: Number of placeholders, 2: Number of arguments passed. */
__( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
$placeholders,
$args_count
),
'4.8.3'
);
/*
* If we don't have enough arguments to match the placeholders,
* return an empty string to avoid a fatal error on PHP 8.
*/
if ( $args_count < $placeholders ) {
$max_numbered_placeholder = ! empty( $matches[3] ) ? max( array_map( 'intval', $matches[3] ) ) : 0;
if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
return '';
}
}
}
}
array_walk( $args, array( $this, 'escape_by_ref' ) );
$query = vsprintf( $query, $args );
return $this->add_placeholder_escape( $query );
}
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