DbConn.php

<?php

class DbConn
{
   private $db; // handle to connection
   
   function __construct()
   {
      global $db_host, $db_user, $db_pass, $db_name;
      
      $this->db = mysql_connect($db_host, $db_user, $db_pass);
      if (!$this->db)
         throw new RuntimeException("Couldn't connect to database");
      
      if (!mysql_select_db($db_name, $this->db))
      {
         mysql_close($this->db);
         throw new RuntimeException("Couldn't find database");
      }
   }
   
   function __destruct()
   {
      #if ($this->db)
      #   mysql_close($this->db);
      #$this->db = FALSE;
   }
   
   /**
    * Executes a SELECT, DESCRIBE, etc. query and returns a DbResult.
    *
    * Accepts additional arguments that will be escaped and
    * inserted into the query.
    *
    * Example:
    * $foo->query("SELECT * FROM users WHERE name = ? AND pass = ?", $name, $pass);
    */
   function query($query)
   {
      $params = func_get_args();
      array_shift($params);
      return $this->query_internal($query, $params);
   }
   
   /**
    * Like query, but returns only the first result (as an object) or 
    * null if none.
    */
   function fetch($query)
   {
      $params = func_get_args();
      array_shift($params);
      $dbr = $this->query_internal($query, $params);
      return $dbr->next();
   }
   
   /**
    * Like query, but returns only the first result (as an assoc array)
    * or null if none.
    */
   function fetch_assoc($query)
   {
      $params = func_get_args();
      array_shift($params);
      $dbr = $this->query_internal($query, $params);
      return $dbr->next_assoc();
   }
   
   /**
    * Like query, but returns only the first result (as an array) or 
    * null if none.
    */
   function fetch_array($query)
   {
      $params = func_get_args();
      array_shift($params);
      $dbr = $this->query_internal($query, $params);
      return $dbr->next_array();
   }
   
   function last_insert_id()
   {
      return mysql_insert_id($this->db);
   }
   
   /**
    * Executes an INSERT, UPDATE, DELETE etc. query and returns
    * number of rows affected.
    *
    * Accepts additional arguments that will be escaped and
    * inserted into the query.
    *
    * Example:
    * $foo->exec("UPDATE users SET name=? WHERE id=?", $name, $id);
    */
   function exec($query)
   {
      $params = func_get_args();
      array_shift($params);
      $formatted = $this->format_query($query, $params);
      
      $result = mysql_query($formatted, $this->db);
      if (!$result)
         throw new RuntimeException(mysql_error($this->db));

      return mysql_affected_rows($this->db);
   }
   
   function format_query($query, $args)
   {
      $helper = new DbFormatHelper();
      $helper->value = $args;
      $helper->count = 0;
      $helper->db = $this->db;

      $result = preg_replace_callback("/\?/", array($helper, 'replace'), $query);
      
      if ($helper->count != count($args))
         throw new RuntimeException("Wrong number of args for query");
      
      #echo $result;
      
      return $result;
   }
   
   private function query_internal($query, $params)
   {
      $formatted = $this->format_query($query, $params);
      
      $result = mysql_query($formatted, $this->db);
      if (!$result)
         throw new RuntimeException(mysql_error($this->db));
      
      return new DbResult($result);
   }
}

class DbResult
{
   private $dbr;
   
   public $length;
   
   function __construct($dbr)
   {
      $this->dbr = $dbr;
      $this->length = mysql_num_rows($dbr);
   }
   
   function __destruct()
   {
      mysql_free_result($this->dbr);
   }
   
   function next()
   {
      return mysql_fetch_object($this->dbr);
   }
   
   function next_assoc()
   {
      return mysql_fetch_assoc($this->dbr);
   }
   
   function next_array()
   {
      return mysql_fetch_array($this->dbr);
   }
}

class DbFormatHelper
{
   public $value;
   public $count;
   public $db;
   
   function replace($match)
   {
      return $this->escape_value($this->value[$this->count++]);
   }

   function escape_value($value)
   {
      switch (gettype($value))
      {
         case "boolean":
            return $value ? "TRUE" : "FALSE";
         case "integer":
         case "double":
            return (string) $value;
         case "string":
            return "'" . mysql_real_escape_string($value, $this->db) . "'";
         case "array":
            $result = '(';
            for ($i = 0; $i < count($value); $i++)
            {
               $result = $result . $this->escape_value($value[$i]);
               if ($i < count($value) - 1)
                  $result = $result . ', ';
            }
            return $result . ')';
         case 'object':
            if (get_class($value) == 'DateTime')
            {
               return "'" . $value->format('Y-m-d H:i:s') . "'";
            }
            throw new RuntimeException("Don't know how to escape arbitrary objects");
         case "NULL":
            return "NULL";
         default:
            throw new RuntimeException("Don't know how to escape type " . gettype($value));
      }
   }
}

?>