582 lines
20 KiB
PHP
582 lines
20 KiB
PHP
<?php
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// $Id$
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/**
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* @file
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* Wrapper for database interface code.
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*/
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/**
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* A hash value to check when outputting database errors, md5('DB_ERROR').
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*
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* @see drupal_error_handler()
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*/
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define('DB_ERROR', 'a515ac9c2796ca0e23adbe92c68fc9fc');
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/**
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* @defgroup database Database abstraction layer
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* @{
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* Allow the use of different database servers using the same code base.
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*
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* Drupal provides a slim database abstraction layer to provide developers with
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* the ability to support multiple database servers easily. The intent of this
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* layer is to preserve the syntax and power of SQL as much as possible, while
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* letting Drupal control the pieces of queries that need to be written
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* differently for different servers and provide basic security checks.
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*
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* Most Drupal database queries are performed by a call to db_query() or
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* db_query_range(). Module authors should also consider using pager_query() for
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* queries that return results that need to be presented on multiple pages, and
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* tablesort_sql() for generating appropriate queries for sortable tables.
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*
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* For example, one might wish to return a list of the most recent 10 nodes
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* authored by a given user. Instead of directly issuing the SQL query
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* @code
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* SELECT n.title, n.body, n.created FROM node n WHERE n.uid = $uid LIMIT 0, 10;
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* @endcode
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* one would instead call the Drupal functions:
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* @code
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* $result = db_query_range('SELECT n.title, n.body, n.created
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* FROM {node} n WHERE n.uid = %d', $uid, 0, 10);
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* while ($node = db_fetch_object($result)) {
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* // Perform operations on $node->body, etc. here.
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* }
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* @endcode
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* Curly braces are used around "node" to provide table prefixing via
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* db_prefix_tables(). The explicit use of a user ID is pulled out into an
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* argument passed to db_query() so that SQL injection attacks from user input
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* can be caught and nullified. The LIMIT syntax varies between database servers,
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* so that is abstracted into db_query_range() arguments. Finally, note the
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* common pattern of iterating over the result set using db_fetch_object().
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*/
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/**
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* Perform an SQL query and return success or failure.
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*
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* @param $sql
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* A string containing a complete SQL query. %-substitution
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* parameters are not supported.
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* @return
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* An array containing the keys:
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* success: a boolean indicating whether the query succeeded
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* query: the SQL query executed, passed through check_plain()
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*/
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function update_sql($sql) {
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$result = db_query($sql, true);
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return array('success' => $result !== FALSE, 'query' => check_plain($sql));
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}
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/**
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* Append a database prefix to all tables in a query.
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*
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* Queries sent to Drupal should wrap all table names in curly brackets. This
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* function searches for this syntax and adds Drupal's table prefix to all
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* tables, allowing Drupal to coexist with other systems in the same database if
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* necessary.
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*
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* @param $sql
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* A string containing a partial or entire SQL query.
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* @return
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* The properly-prefixed string.
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*/
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function db_prefix_tables($sql) {
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global $db_prefix;
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if (is_array($db_prefix)) {
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if (array_key_exists('default', $db_prefix)) {
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$tmp = $db_prefix;
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unset($tmp['default']);
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foreach ($tmp as $key => $val) {
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$sql = strtr($sql, array('{' . $key . '}' => $val . $key));
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}
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return strtr($sql, array('{' => $db_prefix['default'], '}' => ''));
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}
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else {
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foreach ($db_prefix as $key => $val) {
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$sql = strtr($sql, array('{' . $key . '}' => $val . $key));
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}
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return strtr($sql, array('{' => '', '}' => ''));
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}
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}
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else {
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return strtr($sql, array('{' => $db_prefix, '}' => ''));
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}
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}
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/**
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* Activate a database for future queries.
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*
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* If it is necessary to use external databases in a project, this function can
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* be used to change where database queries are sent. If the database has not
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* yet been used, it is initialized using the URL specified for that name in
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* Drupal's configuration file. If this name is not defined, a duplicate of the
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* default connection is made instead.
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*
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* Be sure to change the connection back to the default when done with custom
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* code.
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*
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* @param $name
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* The name assigned to the newly active database connection. If omitted, the
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* default connection will be made active.
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*
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* @return the name of the previously active database or FALSE if non was found.
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*/
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function db_set_active($name = 'default') {
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global $db_url, $db_type, $active_db, $db_prefix;
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static $db_conns, $active_name = FALSE;
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if (empty($db_url)) {
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include_once 'includes/install.inc';
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install_goto('install.php');
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}
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if (!isset($db_conns[$name])) {
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// Initiate a new connection, using the named DB URL specified.
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if (is_array($db_url)) {
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$connect_url = array_key_exists($name, $db_url) ? $db_url[$name] : $db_url['default'];
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}
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else {
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$connect_url = $db_url;
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}
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$db_type = substr($connect_url, 0, strpos($connect_url, '://'));
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$handler = "./includes/database.$db_type.inc";
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if (is_file($handler)) {
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include_once $handler;
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}
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else {
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_db_error_page("The database type '" . $db_type . "' is unsupported. Please use either 'mysql' or 'mysqli' for MySQL, or 'pgsql' for PostgreSQL databases.");
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}
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$db_conns[$name] = db_connect($connect_url);
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// We need to pass around the simpletest database prefix in the request
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// and we put that in the user_agent header.
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if (preg_match("/^simpletest\d+$/", $_SERVER['HTTP_USER_AGENT'])) {
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$db_prefix = $_SERVER['HTTP_USER_AGENT'];
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}
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}
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$previous_name = $active_name;
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// Set the active connection.
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$active_name = $name;
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$active_db = $db_conns[$name];
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return $previous_name;
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}
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/**
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* Helper function to show fatal database errors.
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*
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* Prints a themed maintenance page with the 'Site offline' text,
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* adding the provided error message in the case of 'display_errors'
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* set to on. Ends the page request; no return.
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*
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* @param $error
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* The error message to be appended if 'display_errors' is on.
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*/
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function _db_error_page($error = '') {
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global $db_type;
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drupal_maintenance_theme();
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drupal_set_header('HTTP/1.1 503 Service Unavailable');
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drupal_set_title('Site offline');
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$message = '<p>The site is currently not available due to technical problems. Please try again later. Thank you for your understanding.</p>';
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$message .= '<hr /><p><small>If you are the maintainer of this site, please check your database settings in the <code>settings.php</code> file and ensure that your hosting provider\'s database server is running. For more help, see the <a href="http://drupal.org/node/258">handbook</a>, or contact your hosting provider.</small></p>';
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if ($error && ini_get('display_errors')) {
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$message .= '<p><small>The ' . theme('placeholder', $db_type) . ' error was: ' . theme('placeholder', $error) . '.</small></p>';
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}
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print theme('maintenance_page', $message);
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exit;
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}
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/**
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* Returns a boolean depending on the availability of the database.
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*/
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function db_is_active() {
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global $active_db;
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return !empty($active_db);
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}
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/**
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* Helper function for db_query().
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*/
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function _db_query_callback($match, $init = FALSE) {
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static $args = NULL;
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if ($init) {
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$args = $match;
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return;
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}
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switch ($match[1]) {
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case '%d': // We must use type casting to int to convert FALSE/NULL/(TRUE?)
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return (int) array_shift($args); // We don't need db_escape_string as numbers are db-safe
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case '%s':
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return db_escape_string(array_shift($args));
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case '%n':
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// Numeric values have arbitrary precision, so can't be treated as float.
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// is_numeric() allows hex values (0xFF), but they are not valid.
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$value = trim(array_shift($args));
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return (is_numeric($value) && !stripos($value, 'x')) ? $value : '0';
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case '%%':
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return '%';
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case '%f':
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return (float) array_shift($args);
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case '%b': // binary data
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return db_encode_blob(array_shift($args));
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}
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}
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/**
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* Generate placeholders for an array of query arguments of a single type.
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*
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* Given a Schema API field type, return correct %-placeholders to
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* embed in a query
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*
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* @param $arguments
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* An array with at least one element.
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* @param $type
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* The Schema API type of a field (e.g. 'int', 'text', or 'varchar').
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*/
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function db_placeholders($arguments, $type = 'int') {
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$placeholder = db_type_placeholder($type);
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return implode(',', array_fill(0, count($arguments), $placeholder));
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}
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/**
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* Indicates the place holders that should be replaced in _db_query_callback().
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*/
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define('DB_QUERY_REGEXP', '/(%d|%s|%%|%f|%b|%n)/');
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/**
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* Helper function for db_rewrite_sql.
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*
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* Collects JOIN and WHERE statements via hook_db_rewrite_sql()
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* Decides whether to select primary_key or DISTINCT(primary_key)
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*
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* @param $query
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* Query to be rewritten.
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* @param $primary_table
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* Name or alias of the table which has the primary key field for this query.
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* Typical table names would be: {blocks}, {comments}, {forum}, {node},
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* {menu}, {term_data} or {vocabulary}. However, in most cases the usual
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* table alias (b, c, f, n, m, t or v) is used instead of the table name.
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* @param $primary_field
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* Name of the primary field.
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* @param $args
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* Array of additional arguments.
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* @return
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* An array: join statements, where statements, field or DISTINCT(field).
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*/
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function _db_rewrite_sql($query = '', $primary_table = 'n', $primary_field = 'nid', $args = array()) {
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$where = array();
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$join = array();
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$distinct = FALSE;
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foreach (module_implements('db_rewrite_sql') as $module) {
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$result = module_invoke($module, 'db_rewrite_sql', $query, $primary_table, $primary_field, $args);
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if (isset($result) && is_array($result)) {
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if (isset($result['where'])) {
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$where[] = $result['where'];
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}
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if (isset($result['join'])) {
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$join[] = $result['join'];
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}
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if (isset($result['distinct']) && $result['distinct']) {
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$distinct = TRUE;
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}
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}
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elseif (isset($result)) {
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$where[] = $result;
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}
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}
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$where = empty($where) ? '' : '(' . implode(') AND (', $where) . ')';
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$join = empty($join) ? '' : implode(' ', $join);
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return array($join, $where, $distinct);
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}
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/**
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* Rewrites node, taxonomy and comment queries. Use it for listing queries. Do not
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* use FROM table1, table2 syntax, use JOIN instead.
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*
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* @param $query
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* Query to be rewritten.
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* @param $primary_table
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* Name or alias of the table which has the primary key field for this query.
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* Typical table names would be: {blocks}, {comments}, {forum}, {node},
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* {menu}, {term_data} or {vocabulary}. However, it is more common to use the
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* the usual table aliases: b, c, f, n, m, t or v.
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* @param $primary_field
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* Name of the primary field.
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* @param $args
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* An array of arguments, passed to the implementations of hook_db_rewrite_sql.
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* @return
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* The original query with JOIN and WHERE statements inserted from
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* hook_db_rewrite_sql implementations. nid is rewritten if needed.
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*/
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function db_rewrite_sql($query, $primary_table = 'n', $primary_field = 'nid', $args = array()) {
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list($join, $where, $distinct) = _db_rewrite_sql($query, $primary_table, $primary_field, $args);
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if ($distinct) {
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$query = db_distinct_field($primary_table, $primary_field, $query);
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}
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if (!empty($where) || !empty($join)) {
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$pattern = '{
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# Beginning of the string
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^
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((?P<anonymous_view>
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# Everything within this set of parentheses is named "anonymous view"
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(?:
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[^()]++ # anything not parentheses
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\( (?P>anonymous_view) \) # an open parenthesis, more "anonymous view" and finally a close parenthesis.
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)*
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)[^()]+WHERE)
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}x';
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preg_match($pattern, $query, $matches);
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if ($where) {
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$n = strlen($matches[1]);
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$second_part = substr($query, $n);
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$first_part = substr($matches[1], 0, $n - 5) . " $join WHERE $where AND ( ";
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// PHP 4 does not support strrpos for strings. We emulate it.
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$haystack_reverse = strrev($second_part);
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// No need to use strrev on the needle, we supply GROUP, ORDER, LIMIT
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// reversed.
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foreach (array('PUORG', 'REDRO', 'TIMIL') as $needle_reverse) {
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$pos = strpos($haystack_reverse, $needle_reverse);
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if ($pos !== FALSE) {
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// All needles are five characters long.
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$pos += 5;
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break;
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}
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}
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if ($pos === FALSE) {
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$query = $first_part . $second_part . ')';
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}
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else {
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$query = $first_part . substr($second_part, 0, -$pos) . ')' . substr($second_part, -$pos);
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}
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}
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else {
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$query = $matches[1] . " $join " . substr($query, strlen($matches[1]));
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}
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}
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return $query;
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}
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/**
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* Restrict a dynamic table, column or constraint name to safe characters.
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*
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* Only keeps alphanumeric and underscores.
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*/
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function db_escape_table($string) {
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return preg_replace('/[^A-Za-z0-9_]+/', '', $string);
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}
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/**
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* @} End of "defgroup database".
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*/
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/**
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* @defgroup schemaapi Schema API
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* @{
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*
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* A Drupal schema definition is an array structure representing one or
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* more tables and their related keys and indexes. A schema is defined by
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* hook_schema(), which usually lives in a modulename.install file.
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*
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* By implementing hook_schema() and specifying the tables your module
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* declares, you can easily create and drop these tables on all
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* supported database engines. You don't have to deal with the
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* different SQL dialects for table creation and alteration of the
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* supported database engines.
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*
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* hook_schema() should return an array with a key for each table that
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* the module defines.
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*
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* The following keys are defined:
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*
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* - 'description': A string describing this table and its purpose.
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* References to other tables should be enclosed in
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* curly-brackets. For example, the node_revisions table
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* description field might contain "Stores per-revision title and
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* body data for each {node}."
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* - 'fields': An associative array ('fieldname' => specification)
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* that describes the table's database columns. The specification
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* is also an array. The following specification parameters are defined:
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*
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* - 'description': A string describing this field and its purpose.
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* References to other tables should be enclosed in
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* curly-brackets. For example, the node table vid field
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* description might contain "Always holds the largest (most
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* recent) {node_revisions}.vid value for this nid."
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* - 'type': The generic datatype: 'varchar', 'int', 'serial'
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* 'float', 'numeric', 'text', 'blob' or 'datetime'. Most types
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* just map to the according database engine specific
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* datatypes. Use 'serial' for auto incrementing fields. This
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* will expand to 'int auto_increment' on mysql.
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* - 'size': The data size: 'tiny', 'small', 'medium', 'normal',
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* 'big'. This is a hint about the largest value the field will
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* store and determines which of the database engine specific
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* datatypes will be used (e.g. on MySQL, TINYINT vs. INT vs. BIGINT).
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* 'normal', the default, selects the base type (e.g. on MySQL,
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* INT, VARCHAR, BLOB, etc.).
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*
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* Not all sizes are available for all data types. See
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* db_type_map() for possible combinations.
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* - 'not null': If true, no NULL values will be allowed in this
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* database column. Defaults to false.
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* - 'default': The field's default value. The PHP type of the
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* value matters: '', '0', and 0 are all different. If you
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* specify '0' as the default value for a type 'int' field it
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* will not work because '0' is a string containing the
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* character "zero", not an integer.
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* - 'length': The maximal length of a type 'varchar' or 'text'
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* field. Ignored for other field types.
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* - 'unsigned': A boolean indicating whether a type 'int', 'float'
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* and 'numeric' only is signed or unsigned. Defaults to
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* FALSE. Ignored for other field types.
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* - 'precision', 'scale': For type 'numeric' fields, indicates
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* the precision (total number of significant digits) and scale
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* (decimal digits right of the decimal point). Both values are
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* mandatory. Ignored for other field types.
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*
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* All parameters apart from 'type' are optional except that type
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* 'numeric' columns must specify 'precision' and 'scale'.
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*
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* - 'primary key': An array of one or more key column specifiers (see below)
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* that form the primary key.
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* - 'unique key': An associative array of unique keys ('keyname' =>
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* specification). Each specification is an array of one or more
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* key column specifiers (see below) that form a unique key on the table.
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* - 'indexes': An associative array of indexes ('indexame' =>
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* specification). Each specification is an array of one or more
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* key column specifiers (see below) that form an index on the
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* table.
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*
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* A key column specifier is either a string naming a column or an
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* array of two elements, column name and length, specifying a prefix
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* of the named column.
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*
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* As an example, here is a SUBSET of the schema definition for
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* Drupal's 'node' table. It show four fields (nid, vid, type, and
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* title), the primary key on field 'nid', a unique key named 'vid' on
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* field 'vid', and two indexes, one named 'nid' on field 'nid' and
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* one named 'node_title_type' on the field 'title' and the first four
|
|
* bytes of the field 'type':
|
|
*
|
|
* @code
|
|
* $schema['node'] = array(
|
|
* 'fields' => array(
|
|
* 'nid' => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
|
|
* 'vid' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
|
|
* 'type' => array('type' => 'varchar', 'length' => 32, 'not null' => TRUE, 'default' => ''),
|
|
* 'title' => array('type' => 'varchar', 'length' => 128, 'not null' => TRUE, 'default' => ''),
|
|
* ),
|
|
* 'primary key' => array('nid'),
|
|
* 'unique keys' => array(
|
|
* 'vid' => array('vid')
|
|
* ),
|
|
* 'indexes' => array(
|
|
* 'nid' => array('nid'),
|
|
* 'node_title_type' => array('title', array('type', 4)),
|
|
* ),
|
|
* );
|
|
* @endcode
|
|
*
|
|
* @see drupal_install_schema()
|
|
*/
|
|
|
|
/**
|
|
* Create a new table from a Drupal table definition.
|
|
*
|
|
* @param $ret
|
|
* Array to which query results will be added.
|
|
* @param $name
|
|
* The name of the table to create.
|
|
* @param $table
|
|
* A Schema API table definition array.
|
|
*/
|
|
function db_create_table(&$ret, $name, $table) {
|
|
$statements = db_create_table_sql($name, $table);
|
|
foreach ($statements as $statement) {
|
|
$ret[] = update_sql($statement);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Return an array of field names from an array of key/index column specifiers.
|
|
*
|
|
* This is usually an identity function but if a key/index uses a column prefix
|
|
* specification, this function extracts just the name.
|
|
*
|
|
* @param $fields
|
|
* An array of key/index column specifiers.
|
|
* @return
|
|
* An array of field names.
|
|
*/
|
|
function db_field_names($fields) {
|
|
$ret = array();
|
|
foreach ($fields as $field) {
|
|
if (is_array($field)) {
|
|
$ret[] = $field[0];
|
|
}
|
|
else {
|
|
$ret[] = $field;
|
|
}
|
|
}
|
|
return $ret;
|
|
}
|
|
|
|
/**
|
|
* Given a Schema API field type, return the correct %-placeholder.
|
|
*
|
|
* Embed the placeholder in a query to be passed to db_query and and pass as an
|
|
* argument to db_query a value of the specified type.
|
|
*
|
|
* @param $type
|
|
* The Schema API type of a field.
|
|
* @return
|
|
* The placeholder string to embed in a query for that type.
|
|
*/
|
|
function db_type_placeholder($type) {
|
|
switch ($type) {
|
|
case 'varchar':
|
|
case 'char':
|
|
case 'text':
|
|
case 'datetime':
|
|
return "'%s'";
|
|
|
|
case 'numeric':
|
|
// Numeric values are arbitrary precision numbers. Syntacically, numerics
|
|
// should be specified directly in SQL. However, without single quotes
|
|
// the %s placeholder does not protect against non-numeric characters such
|
|
// as spaces which would expose us to SQL injection.
|
|
return '%n';
|
|
|
|
case 'serial':
|
|
case 'int':
|
|
return '%d';
|
|
|
|
case 'float':
|
|
return '%f';
|
|
|
|
case 'blob':
|
|
return '%b';
|
|
}
|
|
|
|
// There is no safe value to return here, so return something that
|
|
// will cause the query to fail.
|
|
return 'unsupported type ' . $type . 'for db_type_placeholder';
|
|
}
|
|
|
|
/**
|
|
* @} End of "defgroup schemaapi".
|
|
*/
|