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Drupal example source code file (install.inc)

This example Drupal source code file (install.inc) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

PHP - Drupal tags/keywords

array, as, database, encoding, function, language, numeric, or, php, replace, returns, select, sql, text

The install.inc Drupal example source code

<?php
// $Id: install.inc,v 1.14 2010/12/21 21:20:04 webchick Exp $

/**
 * @file
 * Install functions for PostgreSQL embedded database engine.
 */


// PostgreSQL specific install functions

class DatabaseTasks_pgsql extends DatabaseTasks {
  protected $pdoDriver = 'pgsql';

  public function __construct() {
    $this->tasks[] = array(
      'function' => 'checkEncoding',
      'arguments' => array(),
    );
    $this->tasks[] = array(
      'function' => 'checkPHPVersion',
      'arguments' => array(),
    );
    $this->tasks[] = array(
      'function' => 'checkBinaryOutput',
      'arguments' => array(),
    );
    $this->tasks[] = array(
      'function' => 'initializeDatabase',
      'arguments' => array(),
    );
  }

  public function name() {
    return st('PostgreSQL');
  }

  public function minimumVersion() {
    return '8.3';
  }

  /**
   * Check encoding is UTF8.
   */
  protected function checkEncoding() {
    try {
      if (db_query('SHOW server_encoding')->fetchField() == 'UTF8') {
        $this->pass(st('Database is encoded in UTF-8'));
      }
      else {
        $replacements = array(
          '%encoding' => 'UTF8',
          '%driver' => $this->name(),
          '!link' => '<a href="INSTALL.pgsql.txt">INSTALL.pgsql.txt</a>'
        );
        $text  = 'The %driver database must use %encoding encoding to work with Drupal.';
        $text .= 'Recreate the database with %encoding encoding. See !link for more details.';
        $this->fail(st($text, $replacements));
      }
    }
    catch (Exception $e) {
      $this->fail(st('Drupal could not determine the encoding of the database was set to UTF-8'));
    }
  }

  /**
   * Check PHP version.
   *
   * There are two bugs in PDO_pgsql affecting Drupal:
   *
   * - in versions < 5.2.7, PDO_pgsql refuses to insert an empty string into
   *   a NOT NULL BLOB column. See: http://bugs.php.net/bug.php?id=46249
   * - in versions < 5.2.11 and < 5.3.1 that prevents inserting integer values
   *   into numeric columns that exceed the PHP_INT_MAX value.
   *   See: http://bugs.php.net/bug.php?id=48924
   */
  function checkPHPVersion() {
    if (!version_compare(PHP_VERSION, '5.2.11', '>=') || (version_compare(PHP_VERSION, '5.3.0', '>=') && !version_compare(PHP_VERSION, '5.3.1', '>='))) {
      $this->fail(st('The version of PHP you are using has known issues with PostgreSQL. You need to upgrade PHP to 5.2.11, 5.3.1 or greater.'));
    };
  }

  /**
   * Check Binary Output.
   *
   * Unserializing does not work on Postgresql 9 when bytea_output is 'hex'.
   */
  function checkBinaryOutput() {
    // PostgreSQL < 9 doesn't support bytea_output, so verify we are running
    // at least PostgreSQL 9.
    $database_connection = Database::getConnection();
    if (version_compare($database_connection->version(), '9') >= 0) {
      if (!$this->checkBinaryOutputSuccess()) {
        // First try to alter the database. If it fails, raise an error telling
        // the user to do it themselves.
        $connection_options = $database_connection->getConnectionOptions();
        // It is safe to include the database name directly here, because this
        // code is only called when a connection to the database is already
        // established, thus the database name is guaranteed to be a correct
        // value.
        $query = "ALTER DATABASE \"" . $connection_options['database'] . "\" SET bytea_output = 'escape';";
        try {
          db_query($query);
        }
        catch (Exception $e) {
          // Ignore possible errors when the user doesn't have the necessary
          // privileges to ALTER the database.
        }

        // Close the database connection so that the configuration parameter
        // is applied to the current connection.
        db_close();

        // Recheck, if it fails, finally just rely on the end user to do the
        // right thing.
        if (!$this->checkBinaryOutputSuccess()) {
          $replacements = array(
            '%setting' => 'bytea_output',
            '%current_value' => 'hex',
            '%needed_value' => 'escape',
            '!query' => "<code>" . $query . "</code>",
          );
          $this->fail(st("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: !query", $replacements));
        }
      }
    }
  }

  /**
   * Verify that a binary data roundtrip returns the original string.
   */
  protected function checkBinaryOutputSuccess() {
    $bytea_output = db_query("SELECT 'encoding'::bytea AS output")->fetchField();
    return ($bytea_output == 'encoding');
  }

  /**
   * Make PostgreSQL Drupal friendly.
   */
  function initializeDatabase() {
    // We create some functions using global names instead of prefixing them
    // like we do with table names. This is so that we don't double up if more
    // than one instance of Drupal is running on a single database. We therefore
    // avoid trying to create them again in that case.

    try {
      // Create functions.
      db_query('CREATE OR REPLACE FUNCTION "greatest"(numeric, numeric) RETURNS numeric AS
        \'SELECT CASE WHEN (($1 > $2) OR ($2 IS NULL)) THEN $1 ELSE $2 END;\'
        LANGUAGE \'sql\''
      );
      db_query('CREATE OR REPLACE FUNCTION "greatest"(numeric, numeric, numeric) RETURNS numeric AS
        \'SELECT greatest($1, greatest($2, $3));\'
        LANGUAGE \'sql\''
      );
      // Don't use {} around pg_proc table.
      if (!db_query("SELECT COUNT(*) FROM pg_proc WHERE proname = 'rand'")->fetchField()) {
        db_query('CREATE OR REPLACE FUNCTION "rand"() RETURNS float AS
          \'SELECT random();\'
          LANGUAGE \'sql\''
        );
      }

      db_query('CREATE OR REPLACE FUNCTION "substring_index"(text, text, integer) RETURNS text AS
        \'SELECT array_to_string((string_to_array($1, $2)) [1:$3], $2);\'
        LANGUAGE \'sql\''
      );

      // Using || to concatenate in Drupal is not recommeneded because there are
      // database drivers for Drupal that do not support the syntax, however
      // they do support CONCAT(item1, item2) which we can replicate in
      // PostgreSQL. PostgreSQL requires the function to be defined for each
      // different argument variation the function can handle.
      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, anynonarray) RETURNS text AS
        \'SELECT CAST($1 AS text) || CAST($2 AS text);\'
        LANGUAGE \'sql\'
      ');
      db_query('CREATE OR REPLACE FUNCTION "concat"(text, anynonarray) RETURNS text AS
        \'SELECT $1 || CAST($2 AS text);\'
        LANGUAGE \'sql\'
      ');
      db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, text) RETURNS text AS
        \'SELECT CAST($1 AS text) || $2;\'
        LANGUAGE \'sql\'
      ');
      db_query('CREATE OR REPLACE FUNCTION "concat"(text, text) RETURNS text AS
        \'SELECT $1 || $2;\'
        LANGUAGE \'sql\'
      ');

      $this->pass(st('PostgreSQL has initialized itself.'));
    }
    catch (Exception $e) {
      $this->fail(st('Drupal could not be correctly setup with the existing database. Revise any errors.'));
    }
  }
}

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