Efficient mongodb's php paging class (skip is not used)

The mongodb pagination skip+limit pagination looks up all the results first and then skips, which makes it less efficient as the query page progresses.

If the last record of the results of each page can be found through the query conditions, the last record can be used as the query condition to check the next page, so that size records on the page can be checked every time, the efficiency will not be bad.

The code is as follows: mongodb.class.php, page.class.php, test.php

mongodb.class.php mongodb operation class

<?php 
function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')
{
        echo $message, $status_code,PHP_EOL;
        exit;
}
//MongoDB Action class 
class DB 
{
 private $CI;
 private $config_file = 'MongoDB';
 private $connection;
 private $db;
 private $connection_string;

 private $collection = '';
 private $host;
 private $port;
 private $user;
 private $pass;
 private $dbname;
 private $key;
 private $persist;
 private $persist_key;
 private $selects = array();
 private $wheres = array();
 private $sorts = array();
 private $page_sorts = array();
 private $limit = 999999;
 private $offset = 0;
 
 /**
  * --------------------------------------------------------------------------------
  * CONSTRUCTOR
  * --------------------------------------------------------------------------------
  *
  * Automatically check if the Mongo PECL extension has been installed/enabled.
  * Generate the connection string and establish a connection to the MongoDB.
  */
 public function __construct($MONGODB_CONFIG)
 {
  if(!class_exists('Mongo'))
  {
   show_error("The MongoDB PECL extension has not been installed or enabled", 500);
  }
  /**
        $config['mongo_host'] = '221.234.43.144';
        $config['mongo_port'] = 27017;
        $config['mongo_db'] = 'test';
        $config['mongo_user'] = '';
        $config['mongo_pass'] = '';
        $config['mongo_persist'] = TRUE;
         *
         */
  $this->connection_string($MONGODB_CONFIG);
  $this->connect();
 }

 
 /**
  * --------------------------------------------------------------------------------
  * Switch_db
  * --------------------------------------------------------------------------------
  *
  * Switch from default database to a different db
  */
 public function switch_db($database = '')
 {
  if(empty($database))
  {
   show_error("To switch MongoDB databases, a new database name must be specified", 500);
  }
  $this->dbname = $database;
  try
  {
   $this->db = $this->connection->{$this->dbname};
   return(TRUE);
  }
  catch(Exception $e)
  {
   show_error("Unable to switch Mongo Databases: {$e->getMessage()}", 500);
  }
 }
 /**
  * --------------------------------------------------------------------------------
  * SELECT FIELDS
  * --------------------------------------------------------------------------------
  *
  * Determine which fields to include OR which to exclude during the query process.
  * Currently, including and excluding at the same time is not available, so the 
  * $includes array will take precedence over the $excludes array.  If you want to 
  * only choose fields to exclude, leave $includes an empty array().
  *
  * @usage: $this->mongo_db->select(array('foo', 'bar'))->get('foobar');
  */
 public function select($includes = array(), $excludes = array())
 {
   if(!is_array($includes))
   {
    $includes = array();
   }
   if(!is_array($excludes))
   {
    $excludes = array();
   }
   if(!empty($includes))
   {
    foreach($includes as $col)
    {
     $this->selects[$col] = 1;
    }
   }
   else
   {
    foreach($excludes as $col)
    {
     $this->selects[$col] = 0;
    }
   }
   return($this);
 }
 /**
  * --------------------------------------------------------------------------------
  * WHERE PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents based on these search parameters.  The $wheres array should 
  * be an associative array with the field as the key and the value as the search
  * criteria.
  *
  * @usage = $this->mongo_db->where(array('foo' => 'bar'))->get('foobar');
  */
  public function where($wheres = array())
  {
   foreach($wheres as $wh => $val)
   {
    $this->wheres[$wh] = $val;
   }
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE_IN PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is in a given $in array().
  *
  * @usage = $this->mongo_db->where_in('foo', array('bar', 'zoo', 'blah'))->get('foobar');
  */
  public function where_in($field = "", $in = array())
  {
   $this->where_init($field);
   $this->wheres[$field]['$in'] = $in;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE_NOT_IN PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is not in a given $in array().
  *
  * @usage = $this->mongo_db->where_not_in('foo', array('bar', 'zoo', 'blah'))->get('foobar');
  */
  public function where_not_in($field = "", $in = array())
  {
   $this->where_init($field);
   $this->wheres[$field]['$nin'] = $in;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE GREATER THAN PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is greater than $x
  *
  * @usage = $this->mongo_db->where_gt('foo', 20);
  */
  public function where_gt($field = "", $x)
  {
   $this->where_init($field);
   $this->wheres[$field]['$gt'] = $x;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE GREATER THAN OR EQUAL TO PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is greater than or equal to $x
  *
  * @usage = $this->mongo_db->where_gte('foo', 20);
  */
  public function where_gte($field = "", $x)
  {
   $this->where_init($field);
   $this->wheres[$field]['$gte'] = $x;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE LESS THAN PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is less than $x
  *
  * @usage = $this->mongo_db->where_lt('foo', 20);
  */
  public function where_lt($field = "", $x)
  {
   $this->where_init($field);
   $this->wheres[$field]['$lt'] = $x;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE LESS THAN OR EQUAL TO PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is less than or equal to $x
  *
  * @usage = $this->mongo_db->where_lte('foo', 20);
  */
  public function where_lte($field = "", $x)
  {
   $this->where_init($field);
   $this->wheres[$field]['$lte'] = $x;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE BETWEEN PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is between $x and $y
  *
  * @usage = $this->mongo_db->where_between('foo', 20, 30);
  */
  public function where_between($field = "", $x, $y)
  {
   $this->where_init($field);
   $this->wheres[$field]['$gte'] = $x;
   $this->wheres[$field]['$lte'] = $y;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE BETWEEN AND NOT EQUAL TO PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is between but not equal to $x and $y
  *
  * @usage = $this->mongo_db->where_between_ne('foo', 20, 30);
  */
  public function where_between_ne($field = "", $x, $y)
  {
   $this->where_init($field);
   $this->wheres[$field]['$gt'] = $x;
   $this->wheres[$field]['$lt'] = $y;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE NOT EQUAL TO PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is not equal to $x
  *
  * @usage = $this->mongo_db->where_between('foo', 20, 30);
  */
  public function where_ne($field = "", $x)
  {
   $this->where_init($field);
   $this->wheres[$field]['$ne'] = $x;
   return($this);
  }
  /**
  * --------------------------------------------------------------------------------
  * WHERE OR
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the value of a $field is in one or more values
  *
  * @usage = $this->mongo_db->where_or('foo', array( 'foo', 'bar', 'blegh' );
  */
  public function where_or($field = "", $values)
  {
   $this->where_init($field);
   $this->wheres[$field]['$or'] = $values;
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * WHERE AND
  * --------------------------------------------------------------------------------
  *
  * Get the documents where the elements match the specified values
  *
  * @usage = $this->mongo_db->where_and( array ( 'foo' => 1, 'b' => 'someexample' );
  */
  public function where_and( $elements_values = array() ) {
   foreach ( $elements_values as $element => $val ) {
    $this->wheres[$element] = $val;
   }
   return($this);
  }
  /**
  * --------------------------------------------------------------------------------
  * WHERE MOD
  * --------------------------------------------------------------------------------
  *
  * Get the documents where $field % $mod = $result
  *
  * @usage = $this->mongo_db->where_mod( 'foo', 10, 1 );
  */
  public function where_mod( $field, $num, $result ) {
   $this->where_init($field);
   $this->wheres[$field]['$mod'] = array ( $num, $result );
   return($this);
  }
 /**
 * --------------------------------------------------------------------------------
 * Where size
 * --------------------------------------------------------------------------------
 *
 * Get the documents where the size of a field is in a given $size int
 *
 * @usage : $this->mongo_db->where_size('foo', 1)->get('foobar');
 */
 public function where_size($field = "", $size = "")
 {
  $this->_where_init($field);
  $this->wheres[$field]['$size'] = $size;
  return ($this);
 }
 /**
  * --------------------------------------------------------------------------------
  * LIKE PARAMETERS
  * --------------------------------------------------------------------------------
  * 
  * Get the documents where the (string) value of a $field is like a value. The defaults
  * allow for a case-insensitive search.
  *
  * @param $flags
  * Allows for the typical regular expression flags:
  *  i = case insensitive
  *  m = multiline
  *  x = can contain comments
  *  l = locale
  *  s = dotall, "." matches everything, including newlines
  *  u = match unicode
  *
  * @param $enable_start_wildcard
  * If set to anything other than TRUE, a starting line character "^" will be prepended
  * to the search value, representing only searching for a value at the start of 
  * a new line.
  *
  * @param $enable_end_wildcard
  * If set to anything other than TRUE, an ending line character "$" will be appended
  * to the search value, representing only searching for a value at the end of 
  * a line.
  *
  * @usage = $this->mongo_db->like('foo', 'bar', 'im', FALSE, TRUE);
  */
  public function like($field = "", $value = "", $flags = "i", $enable_start_wildcard = TRUE, $enable_end_wildcard = TRUE)
  {
   $field = (string) trim($field);
   $this->where_init($field);
   $value = (string) trim($value);
   $value = quotemeta($value);
   if($enable_start_wildcard !== TRUE)
   {
    $value = "^" . $value;
   }
   if($enable_end_wildcard !== TRUE)
   {
    $value .= "$";
   }
   $regex = "/$value/$flags";
   $this->wheres[$field] = new MongoRegex($regex);
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * ORDER BY PARAMETERS
  * --------------------------------------------------------------------------------
  *
  * Sort the documents based on the parameters passed. To set values to descending order,
  * you must pass values of either -1, FALSE, 'desc', or 'DESC', else they will be
  * set to 1 (ASC).
  *
  * @usage = $this->mongo_db->where_between('foo', 20, 30);
  */
  public function order_by($fields = array())
  {
   foreach($fields as $col => $val)
   {
    if($val == -1 || $val === FALSE || strtolower($val) == 'desc')
    {
     $this->sorts[$col] = -1; 
    }
    else
    {
     $this->sorts[$col] = 1;
    }
   }
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * LIMIT DOCUMENTS
  * --------------------------------------------------------------------------------
  *
  * Limit the result set to $x number of documents
  *
  * @usage = $this->mongo_db->limit($x);
  */
  public function limit($x = 99999) {
   if($x !== NULL && is_numeric($x) && $x >= 1)
   {
    $this->limit = (int) $x;
   }
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * OFFSET DOCUMENTS
  * --------------------------------------------------------------------------------
  *
  * Offset the result set to skip $x number of documents
  *
  * @usage = $this->mongo_db->offset($x);
  */
  public function offset($x = 0)
  {
   if($x !== NULL && is_numeric($x) && $x >= 1)
   {
    $this->offset = (int) $x;
   }
   return($this);
  }
 /**
  * --------------------------------------------------------------------------------
  * GET_WHERE
  * --------------------------------------------------------------------------------
  *
  * Get the documents based upon the passed parameters
  *
  * @usage = $this->mongo_db->get_where('foo', array('bar' => 'something'));
  */
  public function get_where($collection = "", $where = array(), $limit = 99999)
  {
   return($this->where($where)->limit($limit)->get($collection));
  }
 /**
  * --------------------------------------------------------------------------------
  * GET
  * --------------------------------------------------------------------------------
  *
  * Get the documents based upon the passed parameters
  *
  * @usage = $this->mongo_db->get('foo', array('bar' => 'something'));
  */
  public function get($collection = "")
  {
   if(empty($collection))
   {
    show_error("In order to retreive documents from MongoDB, a collection name must be passed", 500);
   }
   $results = array();
   $documents = $this->db->{$collection}->find($this->wheres, $this->selects)->limit((int) $this->limit)->skip((int) $this->offset)->sort($this->sorts);
   $returns = array();
   foreach($documents as $doc):
    $returns[] = $doc;
   endforeach;
  $this->clear();
   return($returns);
  }
 /**
  * --------------------------------------------------------------------------------
  * COUNT
  * --------------------------------------------------------------------------------
  *
  * Count the documents based upon the passed parameters
  *
  * @usage = $this->mongo_db->get('foo');
  */
  public function count($collection = "")
  {
   if(empty($collection))
   {
    show_error("In order to retreive a count of documents from MongoDB, a collection name must be passed", 500);
   }
   $count = $this->db->{$collection}->find($this->wheres)->limit((int) $this->limit)->skip((int) $this->offset)->count();
   $this->clear();
   return($count);
  }

 /**
  *  Since the increase ID implementation 
  * return insert_id
  */
 private function insert_inc($table)
 { 
  $update = array('$inc'=>array('id'=>1));
  $query = array('table'=>$table);
  $command = array(
  'findandmodify'=>'_increase', 
  'update'=>$update,
  'query'=>$query, 
  'new'=>true, 
  'upsert'=>true
  );
  $id = $this->db->command($command);
  return $id['value']['id'];
 }

 /**
  * --------------------------------------------------------------------------------
  * INSERT
  * --------------------------------------------------------------------------------
  *
  * Insert a new document into the passed collection
  *
  * @usage = $this->mongo_db->insert('foo', $data = array());
  */
  public function insert($collection = "", $data = array()) {
   if(empty($collection))
   {
    show_error("No Mongo collection selected to insert into", 500);
   }
   if(count($data) == 0 || !is_array($data))
   {
    show_error("Nothing to insert into Mongo collection or insert is not an array", 500);
   }
   try
   {
   $inc = $this->insert_inc($collection);
   $data['_id'] = $inc;
    $result = $this->db->{$collection}->insert($data, array('fsync' => TRUE));
    if($result['ok'] || $result){
    return true;
   }
   else{
    return false;
   }
   }
   catch(MongoCursorException $e)
   {
    show_error("Insert of data into MongoDB failed: {$e->getMessage()}", 500);
   }
  }
 /**
  * --------------------------------------------------------------------------------
  * UPDATE
  * --------------------------------------------------------------------------------
  *
  * Update a document into the passed collection
  *
  * @usage = $this->mongo_db->update('foo', $data = array());
  */
  public function update($collection = "", $data = array(), $flage = false)
  {
   if(empty($collection))
   {
    show_error("No Mongo collection selected to update", 500);
  }
   if(count($data) == 0 || !is_array($data))
   {
    show_error("Nothing to update in Mongo collection or update is not an array", 500);
  }
  unset($data['_id']);
  if($flage){
   $arr = $this->wheres;
   unset($arr['_id']);
   if(is_array($arr)){
    foreach($arr as $key => $w){
     unset($data[$key]);
    }
   }
  }
  try
   {
    $res = $this->db->{$collection}->update($this->wheres, array('$set' => $data), array('fsync' => TRUE, 'multiple' => FALSE));
   $this->clear();
   return $res;
   }  
   catch(MongoCursorException $e)
   {
    show_error("Update of data into MongoDB failed: {$e->getMessage()}", 500);
   }
  }
 /**
  * --------------------------------------------------------------------------------
  * UPDATE_ALL
  * --------------------------------------------------------------------------------
  *
  * Insert a new document into the passed collection
  *
  * @usage = $this->mongo_db->update_all('foo', $data = array());
  */
  public function update_all($collection = "", $data = array()) {
   if(empty($collection))
   {
    show_error("No Mongo collection selected to update", 500);
   }
   if(count($data) == 0 || !is_array($data))
   {
    show_error("Nothing to update in Mongo collection or update is not an array", 500);
   }
   try
   {
    $this->db->{$collection}->update($this->wheres, array('$set' => $data), array('fsync' => TRUE, 'multiple' => TRUE));
   $this->clear();
    return(TRUE);
   } 
   catch(MongoCursorException $e)
   {
    show_error("Update of data into MongoDB failed: {$e->getMessage()}", 500);
   }
  }
  /**
  * --------------------------------------------------------------------------------
  * DELETE
  * --------------------------------------------------------------------------------
  *
  * delete document from the passed collection based upon certain criteria
  *
  * @usage = $this->mongo_db->delete('foo', $data = array());
  */
  public function delete($collection, $where)
  {
   if(empty($collection))
   {
    show_error("No Mongo collection selected to delete from", 500);
   }
  if(!$where){
   show_error("No data input to delete", 500);
  }
   try
   {
   $this->wheres = $where;
    $this->db->{$collection}->remove($this->wheres);
   $this->clear();
    return(TRUE);
   }
   catch(MongoCursorException $e)
   {
    show_error("Delete of data into MongoDB failed: {$e->getMessage()}", 500);
   }
  }
 /**
  * --------------------------------------------------------------------------------
  * DELETE_ALL
  * --------------------------------------------------------------------------------
  *
  * Delete all documents from the passed collection based upon certain criteria
  *
  * @usage = $this->mongo_db->delete_all('foo', $data = array());
  */
  public function delete_all($collection = "")
  {
     if(empty($collection))
     {
      show_error("No Mongo collection selected to delete from", 500);
    }
   try
   {
    $this->db->{$collection}->remove($this->wheres, array('fsync' => TRUE, 'justOne' => FALSE));
   $this->clear();
    return(TRUE);
   }
   catch(MongoCursorException $e)
   {
    show_error("Delete of data into MongoDB failed: {$e->getMessage()}", 500);
   }
  }
 /**
  * --------------------------------------------------------------------------------
  * ADD_INDEX
  * --------------------------------------------------------------------------------
  *
  * Ensure an index of the keys in a collection with optional parameters. To set values to descending order,
  * you must pass values of either -1, FALSE, 'desc', or 'DESC', else they will be
  * set to 1 (ASC).
  *
  * @usage = $this->mongo_db->add_index($collection, array('first_name' => 'ASC', 'last_name' => -1), array('unique' => TRUE));
  */
 public function add_index($collection = "", $keys = array(), $options = array())
 {
  if(empty($collection))
  {
    show_error("No Mongo collection specified to add index to", 500);
   }
   if(empty($keys) || !is_array($keys))
   {
    show_error("Index could not be created to MongoDB Collection because no keys were specified", 500);
    }

   foreach($keys as $col => $val)
   {
    if($val == -1 || $val === FALSE || strtolower($val) == 'desc')
    {
     $keys[$col] = -1; 
    }
    else
    {
     $keys[$col] = 1;
    }
   }
   if($this->db->{$collection}->ensureIndex($keys, $options) == TRUE)
   {
    $this->clear();
    return($this);
   }
   else
   {
    show_error("An error occured when trying to add an index to MongoDB Collection", 500);
  }
 }
 
 /**
  * --------------------------------------------------------------------------------
  * REMOVE_INDEX
  * --------------------------------------------------------------------------------
  *
  * Remove an index of the keys in a collection. To set values to descending order,
  * you must pass values of either -1, FALSE, 'desc', or 'DESC', else they will be
  * set to 1 (ASC).
  *
  * @usage = $this->mongo_db->remove_index($collection, array('first_name' => 'ASC', 'last_name' => -1));
  */
 public function remove_index($collection = "", $keys = array())
 {
  if(empty($collection))
  {
    show_error("No Mongo collection specified to remove index from", 500);
   }
   if(empty($keys) || !is_array($keys))
   {
    show_error("Index could not be removed from MongoDB Collection because no keys were specified", 500);
   }
   if($this->db->{$collection}->deleteIndex($keys, $options) == TRUE)
   {
    $this->clear();
    return($this);
   }
   else
   {
    show_error("An error occured when trying to remove an index from MongoDB Collection", 500);
  }
 }
 /**
  * --------------------------------------------------------------------------------
  * REMOVE_ALL_INDEXES
  * --------------------------------------------------------------------------------
  *
  * Remove all indexes from a collection.
  *
  * @usage = $this->mongo_db->remove_all_index($collection);
  */
 public function remove_all_indexes($collection = "") {
  if(empty($collection))
  {
    show_error("No Mongo collection specified to remove all indexes from", 500);
   }
   $this->db->{$collection}->deleteIndexes();
   $this->clear();
   return($this);
 }
 /**
  * --------------------------------------------------------------------------------
  * LIST_INDEXES
  * --------------------------------------------------------------------------------
  *
  * Lists all indexes in a collection.
  *
  * @usage = $this->mongo_db->list_indexes($collection);
  */
 public function list_indexes($collection = "") {
  if(empty($collection))
  {
    show_error("No Mongo collection specified to remove all indexes from", 500);
   }
   return($this->db->{$collection}->getIndexInfo());
 }
 /**
  * --------------------------------------------------------------------------------
  * DROP COLLECTION
  * --------------------------------------------------------------------------------
  *
  * Removes the specified collection from the database.  Be careful because this
  *  can have some very large issues in production!
  */
  public function drop_collection($collection = "")
  {
    if(empty($collection))
   {
      show_error("No Mongo collection specified to drop from database", 500);
    }
    $this->db->{$collection}->drop();
    return TRUE;
  }

 /**
  * --------------------------------------------------------------------------------
  * CONNECT TO MONGODB
  * --------------------------------------------------------------------------------
  *
  * Establish a connection to MongoDB using the connection string generated in
  * the connection_string() method.  If 'mongo_persist_key' was set to true in the
  * config file, establish a persistent connection.  We allow for only the 'persist'
  * option to be set because we want to establish a connection immediately.
  */
 private function connect() {
  $options = array();
  if($this->persist === TRUE)
  {
   $options['persist'] = isset($this->persist_key) && !empty($this->persist_key) ? $this->persist_key : 'ci_mongo_persist';
  }
  try
  {
   $this->connection = new Mongo($this->connection_string, $options);
   $this->db = $this->connection->{$this->dbname};
   return($this); 
  } 
  catch(MongoConnectionException $e)
  {
   show_error("Unable to connect to MongoDB: {$e->getMessage()}", 500);
  }
 }
 /**
  * --------------------------------------------------------------------------------
  * BUILD CONNECTION STRING
  * --------------------------------------------------------------------------------
  *
  * Build the connection string from the config file.
  */
 private function connection_string($MONGODB_CONFIG) 
 {
  $this->host = trim($MONGODB_CONFIG['HOST']);
  $this->port = trim($MONGODB_CONFIG['PORT']);
  $this->user = trim($MONGODB_CONFIG['USER']);
  $this->pass = trim($MONGODB_CONFIG['PWD']);
  $this->dbname = trim($MONGODB_CONFIG['DATABASE']);
  $this->persist = trim($MONGODB_CONFIG['PERSIST']);
  $this->persist_key = trim($MONGODB_CONFIG['PERSIST_KEY']);
  $connection_string = "mongodb://";
  if(empty($this->host))
  {
   show_error("The Host must be set to connect to MongoDB", 500);
  }
  if(empty($this->dbname))
  {
   show_error("The Database must be set to connect to MongoDB", 500);
  }
  if(!empty($this->user) && !empty($this->pass))
  {
   $connection_string .= "{$this->user}:{$this->pass}@";
  }
  if(isset($this->port) && !empty($this->port))
  {
   $connection_string .= "{$this->host}:{$this->port}/{$this->dbname}";
  }
  else
  {
   $connection_string .= "{$this->host}";
  }
  $this->connection_string = trim($connection_string);
 }
 /**
  * --------------------------------------------------------------------------------
  * CLEAR
  * --------------------------------------------------------------------------------
  *
  * Resets the class variables to default settings
  */
 private function clear()
 {
  $this->selects = array();
  $this->wheres = array();
  $this->limit = NULL;
  $this->offset = NULL;
  $this->sorts = array();
 }
 /**
  * --------------------------------------------------------------------------------
  * WHERE INITIALIZER
  * --------------------------------------------------------------------------------
  *
  * Prepares parameters for insertion in $wheres array().
  */
 private function where_init($param) 
 {
  if(!isset($this->wheres[$param]))
  {
   $this->wheres[$param] = array();
   }
 }

 /**
  * --------------------------------------------------------------------------------
  *  Set the table 
  * --------------------------------------------------------------------------------
  *   Parameters: 
  *  $table  The name of the table 
  */
 public function set_table($table){
  $this->collection = $table;
 }

 /**
  * --------------------------------------------------------------------------------
  *  To get the name of the table 
  * --------------------------------------------------------------------------------
  */
 public function get_table(){
  return $this->collection;
 }

 /**
  * --------------------------------------------------------------------------------
  *  Set table sort 
  * --------------------------------------------------------------------------------
  *   Parameters: 
  *  $orderby  The sorting 
  */
 public function set_orderby($orderby){
  $this->page_sorts = $orderby;
 }

 
 /**
  * --------------------------------------------------------------------------------
  *  Gets the left result set 
  * --------------------------------------------------------------------------------
  *   Parameters: 
  *  $left  The number on the left 
  *  $last  Locate the value of the current page 
  *  $size  The page size 
  */
 public function get_left($left, $last, $size = PAGE_SIZE){
  if($last){
   $order = $this->nor_orderby();
   if($this->page_sorts[$this->key] == -1){
    $this->where_gt($this->key, $last);
   } else {
     $this->where_lt($this->key, $last);
   }
   return $this->limit($left * $size)->order_by($order)->get($this->collection); 
  }
 }

 
 /**
  * --------------------------------------------------------------------------------
  *  Gets the right result set 
  * --------------------------------------------------------------------------------
  *   Parameters: 
  *  $right  The number shown on the right 
  *  $last  Locate the value of the current page 
  *  $size  The page size 
  */
 public function get_right($right, $last, $size = PAGE_SIZE){
  if($last){
   if($this->page_sorts[$this->key] == -1){
    $this->where_lte($this->key, $last);
   } else {
    $this->where_gte($this->key, $last);
   }
  }
  return $this->limit($right * $size + 1)->order_by($this->page_sorts)->get($this->collection);
 }

 /**
  * --------------------------------------------------------------------------------
  *  Set up the key
  * --------------------------------------------------------------------------------
  *   Parameters: 
  *  $key  Sets the index primary key 
  */
 public function set_key($key){
  $this->key = $key;
 }

 /**
  * --------------------------------------------------------------------------------
  *  complementation 
  * -------------------------------------------------------------------------------- 
  */
 private function nor_orderby(){
  foreach($this->page_sorts as $key => $order){
   if($order == -1){
    $orderby[$key] = 1;
   }else{
    $orderby[$key] = -1;
   }   
  }
  return $orderby;
 }

 /**
  * --------------------------------------------------------------------------------
  *  To get on 1 The value of the page 
  * -------------------------------------------------------------------------------- 
  *   Parameters: 
  *  $last  Locate the value of the current page 
  *  $size  The page size 
  */
 public function get_prev($last, $size = PAGE_SIZE){
  if($last){
   if($this->page_sorts[$this->key] == 1){
    $this->where_lt($this->key,$last)->order_by(array($this->key => -1));
   } else {
    $this->where_gt($this->key,$last)->order_by(array($this->key => 1));
   }
   $result = $this->limit($size)->get($this->collection);
  }
  return $result[$size - 1][$this->key];
 }

  /**
  * --------------------------------------------------------------------------------
  *  To obtain the 1 The value of the page 
  * -------------------------------------------------------------------------------- 
  *   Parameters: 
  *  $last  Locate the value of the current page 
  *  $size  The page size 
  */
 public function get_next($last, $size = PAGE_SIZE){
  if($last){
   if($this->page_sorts[$this->key] == 1){
    $this->where_gte($this->key,$last);
   } else {
    $this->where_lte($this->key,$last);
   }
  }
  $result = $this->limit($size+1)->order_by($this->page_sorts)->get($this->collection);
  return $result[$size][$this->key];
 }

 /**
  * --------------------------------------------------------------------------------
  *  To obtain the final 1 The value of the page 
  * -------------------------------------------------------------------------------- 
  *   Parameters: 
  *  $size  The page size 
  */
 public function get_last($size = PAGE_SIZE){
  $res = $this->count($this->collection) % $size;
  $order = $this->nor_orderby();
  if($res > 0){
   $result = $this->limit($res)->order_by($order)->get($this->collection);
   return $result[$res - 1][$this->key];
  }else{
   $result = $this->limit($size)->order_by($order)->get($this->collection);
   return $result[$size - 1][$this->key];
  }
 }

 /**
  * --------------------------------------------------------------------------------
  *  Paging query 
  * -------------------------------------------------------------------------------- 
  *   Parameters: 
  *  $last  Locate the value of the current page 
  *  $size  The page size 
  */
 public function page_query($last, $size = PAGE_SIZE){
  if($last){
   if($this->page_sorts[$this->key]==1){
    $this->where_gte($this->key,$last);
   } else {
    $this->where_lte($this->key,$last);
   }
  }
  return $this->limit($size)->order_by($this->page_sorts)->get($this->collection);
 } 

 /**
  *  Batch execution code _ insert 
  * @param String $collection
  * @param 2 Dimensional array  $code 
  */
 public function execute_insert($collection,$code){
  // will 2 Dimensional array splitting js format 
  $strcode='';
  foreach($code as $k=>$v){
   foreach($v as $kk=>$vv){
    $strcode.='db.getCollection("'.$collection.'").insert({ "'.$kk.'":"'.$vv.'" });';
   }    
  }
 // retrun array([ok]=>1);
  return $this->db->execute($code);  
 }
}
?>

page.class.php mongodb paging logic class

<?php
db = $DB;
  $this->count = $this->db->count($this->db->get_table());
  $url = SITE_ROOT.strtolower(CLASS_NAME).'/'.METHOD_NAME;
  $this->url = $this->url ? $this->url : $url;
  $set = $set ? $set : 5;
  $this->set = $set;
  $size = $size ? $size : PAGE_SIZE;
  $this->size = $size;
  $this->last = $last;
  $this->prev = $DB->get_prev($this->last);
  $this->next = $DB->get_next($this->last);
  //$this->page = GET::UINT('page');
  $this->page = $this->page ? $this->page : 1;
  $this->total = @ceil($this->count / $this->size);
  $this->key = $key;
  $this->orderby = $orderby; 
 }

 // Output paging link 
 public function get_link(){
  if($this->total != 1){
   $this->get_first();
   $this->get_prev();
   $this->get_center();
   $this->get_next();
   $this->get_last();
   $this->get_turnto();
  }
  if($this->link){
   $this->link = $this->turnto.$this->link.' A total of '.number_format($this->total).' page  '.number_format($this->count).' records ';
  }
  if($this->turnto){
   $this->link .= '';
  }
  return $this->link;
 }

 // Gets the number shown on the left 
 public function get_left(){
  return  $this->left = ($this->set - $this->page >= 0) ? ($this->page - 1) : $this->set;
 }

 // Gets the number shown on the right 
 public function get_right(){
  return $this->right = ($this->total - $this->page > $this->set) ? $this->set : ($this->total - $this->page);
 }

 // Set the result set on the left 
 public function set_left_result($left_result){
  $this->leftresult = $left_result;
 }

 // Set the result set on the right 
 public function set_right_result($right_result){
  $this->rightresult = $right_result;
 }

 // Set sort conditions 
 public function set_orderby($orderby){
  $this->orderby = $orderby;
 }

 // Set the final 1 page 
 public function set_last($last){
  $this->lastd = $last;
 } 

 // Set the number of pages to display in the middle 
 public function set($set){
  $this->set = $set;
 }

 // Access to the home page 
 private function get_first(){
  if($this->page != 1){
   if($this->total > 0){
    $this->link.=' Home page ';
   }
  }
 }

 // To get on 1 page 
 private function get_prev(){
  if($this->prev){
   $this->link.=' on 1 page ';
  }
 }

 // The middle shows 
 private function get_center(){
  $start = ($this->page - $this->set) <= 0 ? 1 : ($this->page - $this->set);  
  $end = ($this->page + $this->set + 1 >= $this->total) ? $this->total + 1 : ($this->page + $this->set + 1);
  $ii = $this->left;
  $iii = 0;
  // Display left 
  for($i = $start; $i < $end; $i++, $ii--, $iii++){
   if($this->page == $i){
    $this->link.=''.$i.'';
   }else{
    $the_id = $ii * $this->size - 1;
    if($the_id > 0){
     $this->link.=''.$i.'';
    }else{
     $the_id = ($iii - $this->left) * $this->size;
     $this->link.=''.$i.'';
    }    
   }
  }
 }
 // To obtain the 1 page 
 private function get_next(){
  if($this->next){
   $this->link.=' Under the 1 page ';
  }
 }

 // To get back 
 private function get_last(){
  if($this->page != $this->total){
   $this->link.=' back ';
  }
 }

 // Jump to 
 private function get_turnto(){
  $this->turnto = '
 Turn to the first  <input type="text" name="p" style="width:25px;text-align:center">  page ';
 }

 // complementation 
 public function nor_orderby(){
  foreach($this->orderby as $key => $order){
   if($order==-1){
    $orderby[$key] = 1;
   }else{
    $orderby[$key] = -1;
   }   
  }
  return $orderby;
 }

 // Set up the key
 public function set_key($key){
  $this->key = $key;
 }

 // paging 
 public function show(){
  $this->set_key($this->key);
  $this->set_orderby($this->orderby);
  $left = $this->get_left();
  $right = $this->get_right();
  $leftresult = $this->db->get_left($left, $this->last);
  $rightresult = $this->db->get_right($right, $this->last);
  $this->set_left_result($leftresult);
  $this->set_right_result($rightresult);
  $last = $this->db->get_last();
  $this->set_last($last); 
  return $this->get_link();
 }
}
/*       Call example rockmongo
  global $DB;
  $lastid = GET::UINT('id');
  $table = 'log';
  $key = '_id';
  $orderby = array($key => -1);

  $DB->set_table($table);
  $DB->set_key($key);
  $DB->set_orderby($orderby);

  $log = $DB->page_query($lastid);
  $page = new Page($lastid, $key, $orderby);
  $pager = $page->show();
*/
?>

test.php test code

<?php
  include "page.class.php";
  include "mongodb.class.php";
  define(PAGE_SIZE, 5);// The size of each page 
  $config['HOST'] = '127.0.0.1';
  $config['PORT'] = 20081;  //mongodb port 
  $config['DATABASE'] = 'domain';//mongodb The database name 
  $config['USER'] = '';
  $config['PWD'] = '';
  $config['PERSIST'] = TRUE;
  $DB = new DB($config);
  $table = 'whois'; //mongodb collection The name 
  $key = '_id';
  $orderby = array($key => -1);
  $DB->set_table($table);
  $DB->set_key($key);
  $DB->set_orderby($orderby);
  $log = $DB->page_query($lastid,5);
  $page = new Page($lastid, $key, $orderby);
  echo $pager = $page->show();

?>