Connection.php in Drupal 8

Namespace

Drupal\Core\Database\Driver\pgsql

File

core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php

<?php

namespace Drupal\Core\Database\Driver\pgsql;

use Drupal\Core\Database\Database;
use Drupal\Core\Database\Connection as DatabaseConnection;
use Drupal\Core\Database\DatabaseAccessDeniedException;
use Drupal\Core\Database\DatabaseNotFoundException;

/**
 * @addtogroup database
 * @{
 */

/**
 * PostgreSQL implementation of \Drupal\Core\Database\Connection.
 */
class Connection extends DatabaseConnection {

  /**
   * The name by which to obtain a lock for retrieve the next insert id.
   */
  const POSTGRESQL_NEXTID_LOCK = 1000;

  /**
   * Error code for "Unknown database" error.
   */
  const DATABASE_NOT_FOUND = 7;

  /**
   * Error code for "Connection failure" errors.
   *
   * Technically this is an internal error code that will only be shown in the
   * PDOException message. It will need to get extracted.
   */
  const CONNECTION_FAILURE = '08006';

  /**
   * A map of condition operators to PostgreSQL operators.
   *
   * In PostgreSQL, 'LIKE' is case-sensitive. ILIKE should be used for
   * case-insensitive statements.
   */
  protected static $postgresqlConditionOperatorMap = [
    'LIKE' => [
      'operator' => 'ILIKE',
    ],
    'LIKE BINARY' => [
      'operator' => 'LIKE',
    ],
    'NOT LIKE' => [
      'operator' => 'NOT ILIKE',
    ],
    'REGEXP' => [
      'operator' => '~*',
    ],
    'NOT REGEXP' => [
      'operator' => '!~*',
    ],
  ];

  /**
   * The list of PostgreSQL reserved key words.
   *
   * @see http://www.postgresql.org/docs/9.4/static/sql-keywords-appendix.html
   */
  protected $postgresqlReservedKeyWords = [
    'all',
    'analyse',
    'analyze',
    'and',
    'any',
    'array',
    'as',
    'asc',
    'asymmetric',
    'authorization',
    'binary',
    'both',
    'case',
    'cast',
    'check',
    'collate',
    'collation',
    'column',
    'concurrently',
    'constraint',
    'create',
    'cross',
    'current_catalog',
    'current_date',
    'current_role',
    'current_schema',
    'current_time',
    'current_timestamp',
    'current_user',
    'default',
    'deferrable',
    'desc',
    'distinct',
    'do',
    'else',
    'end',
    'except',
    'false',
    'fetch',
    'for',
    'foreign',
    'freeze',
    'from',
    'full',
    'grant',
    'group',
    'having',
    'ilike',
    'in',
    'initially',
    'inner',
    'intersect',
    'into',
    'is',
    'isnull',
    'join',
    'lateral',
    'leading',
    'left',
    'like',
    'limit',
    'localtime',
    'localtimestamp',
    'natural',
    'not',
    'notnull',
    'null',
    'offset',
    'on',
    'only',
    'or',
    'order',
    'outer',
    'over',
    'overlaps',
    'placing',
    'primary',
    'references',
    'returning',
    'right',
    'select',
    'session_user',
    'similar',
    'some',
    'symmetric',
    'table',
    'tablesample',
    'then',
    'to',
    'trailing',
    'true',
    'union',
    'unique',
    'user',
    'using',
    'variadic',
    'verbose',
    'when',
    'where',
    'window',
    'with',
  ];

  /**
   * Constructs a connection object.
   */
  public function __construct(\PDO $connection, array $connection_options) {
    parent::__construct($connection, $connection_options);

    // This driver defaults to transaction support, except if explicitly passed FALSE.
    $this->transactionSupport = !isset($connection_options['transactions']) || $connection_options['transactions'] !== FALSE;

    // Transactional DDL is always available in PostgreSQL,
    // but we'll only enable it if standard transactions are.
    $this->transactionalDDLSupport = $this->transactionSupport;
    $this->connectionOptions = $connection_options;

    // Force PostgreSQL to use the UTF-8 character set by default.
    $this->connection
      ->exec("SET NAMES 'UTF8'");

    // Execute PostgreSQL init_commands.
    if (isset($connection_options['init_commands'])) {
      $this->connection
        ->exec(implode('; ', $connection_options['init_commands']));
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function open(array &$connection_options = []) {

    // Default to TCP connection on port 5432.
    if (empty($connection_options['port'])) {
      $connection_options['port'] = 5432;
    }

    // PostgreSQL in trust mode doesn't require a password to be supplied.
    if (empty($connection_options['password'])) {
      $connection_options['password'] = NULL;
    }
    else {
      $connection_options['password'] = str_replace('\\', '\\\\', $connection_options['password']);
    }
    $connection_options['database'] = !empty($connection_options['database']) ? $connection_options['database'] : 'template1';
    $dsn = 'pgsql:host=' . $connection_options['host'] . ' dbname=' . $connection_options['database'] . ' port=' . $connection_options['port'];

    // Allow PDO options to be overridden.
    $connection_options += [
      'pdo' => [],
    ];
    $connection_options['pdo'] += [
      \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
      // Prepared statements are most effective for performance when queries
      // are recycled (used several times). However, if they are not re-used,
      // prepared statements become inefficient. Since most of Drupal's
      // prepared queries are not re-used, it should be faster to emulate
      // the preparation than to actually ready statements for re-use. If in
      // doubt, reset to FALSE and measure performance.
      \PDO::ATTR_EMULATE_PREPARES => TRUE,
      // Convert numeric values to strings when fetching.
      \PDO::ATTR_STRINGIFY_FETCHES => TRUE,
    ];
    try {
      $pdo = new \PDO($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
    } catch (\PDOException $e) {
      if (static::getSQLState($e) == static::CONNECTION_FAILURE) {
        if (strpos($e
          ->getMessage(), 'password authentication failed for user') !== FALSE) {
          throw new DatabaseAccessDeniedException($e
            ->getMessage(), $e
            ->getCode(), $e);
        }
        elseif (strpos($e
          ->getMessage(), 'database') !== FALSE && strpos($e
          ->getMessage(), 'does not exist') !== FALSE) {
          throw new DatabaseNotFoundException($e
            ->getMessage(), $e
            ->getCode(), $e);
        }
      }
      throw $e;
    }
    return $pdo;
  }

  /**
   * {@inheritdoc}
   */
  public function query($query, array $args = [], $options = []) {
    $options += $this
      ->defaultOptions();

    // The PDO PostgreSQL driver has a bug which doesn't type cast booleans
    // correctly when parameters are bound using associative arrays.
    // @see http://bugs.php.net/bug.php?id=48383
    foreach ($args as &$value) {
      if (is_bool($value)) {
        $value = (int) $value;
      }
    }

    // We need to wrap queries with a savepoint if:
    // - Currently in a transaction.
    // - A 'mimic_implicit_commit' does not exist already.
    // - The query is not a savepoint query.
    $wrap_with_savepoint = $this
      ->inTransaction() && !isset($this->transactionLayers['mimic_implicit_commit']) && !(is_string($query) && (stripos($query, 'ROLLBACK TO SAVEPOINT ') === 0 || stripos($query, 'RELEASE SAVEPOINT ') === 0 || stripos($query, 'SAVEPOINT ') === 0));
    if ($wrap_with_savepoint) {

      // Create a savepoint so we can rollback a failed query. This is so we can
      // mimic MySQL and SQLite transactions which don't fail if a single query
      // fails. This is important for tables that are created on demand. For
      // example, \Drupal\Core\Cache\DatabaseBackend.
      $this
        ->addSavepoint();
      try {
        $return = parent::query($query, $args, $options);
        $this
          ->releaseSavepoint();
      } catch (\Exception $e) {
        $this
          ->rollbackSavepoint();
        throw $e;
      }
    }
    else {
      $return = parent::query($query, $args, $options);
    }
    return $return;
  }
  public function prepareQuery($query) {

    // mapConditionOperator converts some operations (LIKE, REGEXP, etc.) to
    // PostgreSQL equivalents (ILIKE, ~*, etc.). However PostgreSQL doesn't
    // automatically cast the fields to the right type for these operators,
    // so we need to alter the query and add the type-cast.
    return parent::prepareQuery(preg_replace('/ ([^ ]+) +(I*LIKE|NOT +I*LIKE|~\\*|!~\\*) /i', ' ${1}::text ${2} ', $query));
  }
  public function queryRange($query, $from, $count, array $args = [], array $options = []) {
    return $this
      ->query($query . ' LIMIT ' . (int) $count . ' OFFSET ' . (int) $from, $args, $options);
  }
  public function queryTemporary($query, array $args = [], array $options = []) {
    $tablename = $this
      ->generateTemporaryTableName();
    $this
      ->query('CREATE TEMPORARY TABLE {' . $tablename . '} AS ' . $query, $args, $options);
    return $tablename;
  }

  /**
   * {@inheritdoc}
   */
  public function escapeField($field) {
    $escaped = parent::escapeField($field);

    // Remove any invalid start character.
    $escaped = preg_replace('/^[^A-Za-z0-9_]/', '', $escaped);

    // The pgsql database driver does not support field names that contain
    // periods (supported by PostgreSQL server) because this method may be
    // called by a field with a table alias as part of SQL conditions or
    // order by statements. This will consider a period as a table alias
    // identifier, and split the string at the first period.
    if (preg_match('/^([A-Za-z0-9_]+)"?[.]"?([A-Za-z0-9_.]+)/', $escaped, $parts)) {
      $table = $parts[1];
      $column = $parts[2];

      // Use escape alias because escapeField may contain multiple periods that
      // need to be escaped.
      $escaped = $this
        ->escapeTable($table) . '.' . $this
        ->escapeAlias($column);
    }
    else {
      $escaped = $this
        ->doEscape($escaped);
    }
    return $escaped;
  }

  /**
   * {@inheritdoc}
   */
  public function escapeAlias($field) {
    $escaped = preg_replace('/[^A-Za-z0-9_]+/', '', $field);
    $escaped = $this
      ->doEscape($escaped);
    return $escaped;
  }

  /**
   * {@inheritdoc}
   */
  public function escapeTable($table) {
    $escaped = parent::escapeTable($table);

    // Ensure that each part (database, schema and table) of the table name is
    // properly and independently escaped.
    $parts = explode('.', $escaped);
    $parts = array_map([
      $this,
      'doEscape',
    ], $parts);
    $escaped = implode('.', $parts);
    return $escaped;
  }

  /**
   * Escape a string if needed.
   *
   * @param $string
   *   The string to escape.
   *
   * @return string
   *   The escaped string.
   */
  protected function doEscape($string) {

    // Quote identifier to make it case-sensitive.
    if (preg_match('/[A-Z]/', $string)) {
      $string = '"' . $string . '"';
    }
    elseif (in_array(strtolower($string), $this->postgresqlReservedKeyWords)) {

      // Quote the string for PostgreSQL reserved key words.
      $string = '"' . $string . '"';
    }
    return $string;
  }
  public function driver() {
    return 'pgsql';
  }
  public function databaseType() {
    return 'pgsql';
  }

  /**
   * Overrides \Drupal\Core\Database\Connection::createDatabase().
   *
   * @param string $database
   *   The name of the database to create.
   *
   * @throws \Drupal\Core\Database\DatabaseNotFoundException
   */
  public function createDatabase($database) {

    // Escape the database name.
    $database = Database::getConnection()
      ->escapeDatabase($database);

    // If the PECL intl extension is installed, use it to determine the proper
    // locale.  Otherwise, fall back to en_US.
    if (class_exists('Locale')) {
      $locale = \Locale::getDefault();
    }
    else {
      $locale = 'en_US';
    }
    try {

      // Create the database and set it as active.
      $this->connection
        ->exec("CREATE DATABASE {$database} WITH TEMPLATE template0 ENCODING='utf8' LC_CTYPE='{$locale}.utf8' LC_COLLATE='{$locale}.utf8'");
    } catch (\Exception $e) {
      throw new DatabaseNotFoundException($e
        ->getMessage());
    }
  }
  public function mapConditionOperator($operator) {
    return isset(static::$postgresqlConditionOperatorMap[$operator]) ? static::$postgresqlConditionOperatorMap[$operator] : NULL;
  }

  /**
   * Retrieve a the next id in a sequence.
   *
   * PostgreSQL has built in sequences. We'll use these instead of inserting
   * and updating a sequences table.
   */
  public function nextId($existing = 0) {

    // Retrieve the name of the sequence. This information cannot be cached
    // because the prefix may change, for example, like it does in simpletests.
    $sequence_name = $this
      ->makeSequenceName('sequences', 'value');

    // When PostgreSQL gets a value too small then it will lock the table,
    // retry the INSERT and if it's still too small then alter the sequence.
    $id = $this
      ->query("SELECT nextval('" . $sequence_name . "')")
      ->fetchField();
    if ($id > $existing) {
      return $id;
    }

    // PostgreSQL advisory locks are simply locks to be used by an
    // application such as Drupal. This will prevent other Drupal processes
    // from altering the sequence while we are.
    $this
      ->query("SELECT pg_advisory_lock(" . self::POSTGRESQL_NEXTID_LOCK . ")");

    // While waiting to obtain the lock, the sequence may have been altered
    // so lets try again to obtain an adequate value.
    $id = $this
      ->query("SELECT nextval('" . $sequence_name . "')")
      ->fetchField();
    if ($id > $existing) {
      $this
        ->query("SELECT pg_advisory_unlock(" . self::POSTGRESQL_NEXTID_LOCK . ")");
      return $id;
    }

    // Reset the sequence to a higher value than the existing id.
    $this
      ->query("ALTER SEQUENCE " . $sequence_name . " RESTART WITH " . ($existing + 1));

    // Retrieve the next id. We know this will be as high as we want it.
    $id = $this
      ->query("SELECT nextval('" . $sequence_name . "')")
      ->fetchField();
    $this
      ->query("SELECT pg_advisory_unlock(" . self::POSTGRESQL_NEXTID_LOCK . ")");
    return $id;
  }

  /**
   * {@inheritdoc}
   */
  public function getFullQualifiedTableName($table) {
    $options = $this
      ->getConnectionOptions();
    $prefix = $this
      ->tablePrefix($table);

    // The fully qualified table name in PostgreSQL is in the form of
    // <database>.<schema>.<table>, so we have to include the 'public' schema in
    // the return value.
    return $options['database'] . '.public.' . $prefix . $table;
  }

  /**
   * Add a new savepoint with an unique name.
   *
   * The main use for this method is to mimic InnoDB functionality, which
   * provides an inherent savepoint before any query in a transaction.
   *
   * @param $savepoint_name
   *   A string representing the savepoint name. By default,
   *   "mimic_implicit_commit" is used.
   *
   * @see Drupal\Core\Database\Connection::pushTransaction()
   */
  public function addSavepoint($savepoint_name = 'mimic_implicit_commit') {
    if ($this
      ->inTransaction()) {
      $this
        ->pushTransaction($savepoint_name);
    }
  }

  /**
   * Release a savepoint by name.
   *
   * @param $savepoint_name
   *   A string representing the savepoint name. By default,
   *   "mimic_implicit_commit" is used.
   *
   * @see Drupal\Core\Database\Connection::popTransaction()
   */
  public function releaseSavepoint($savepoint_name = 'mimic_implicit_commit') {
    if (isset($this->transactionLayers[$savepoint_name])) {
      $this
        ->popTransaction($savepoint_name);
    }
  }

  /**
   * Rollback a savepoint by name if it exists.
   *
   * @param $savepoint_name
   *   A string representing the savepoint name. By default,
   *   "mimic_implicit_commit" is used.
   */
  public function rollbackSavepoint($savepoint_name = 'mimic_implicit_commit') {
    if (isset($this->transactionLayers[$savepoint_name])) {
      $this
        ->rollBack($savepoint_name);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function upsert($table, array $options = []) {

    // Use the (faster) native Upsert implementation for PostgreSQL >= 9.5.
    if (version_compare($this
      ->version(), '9.5', '>=')) {
      $class = $this
        ->getDriverClass('NativeUpsert');
    }
    else {
      $class = $this
        ->getDriverClass('Upsert');
    }
    return new $class($this, $table, $options);
  }

}

/**
 * @} End of "addtogroup database".
 */

Classes

Name	Description
Connection	PostgreSQL implementation of \Drupal\Core\Database\Connection.