Making POST array persistent

(Originally posted in this topic [url=http://www.codeigniter.com/forums/viewthread/312/]pagination and post variables[/url])

If the values from the [i][b]$_POST[/b][/i] array are used in a database query to extract a subset of records from the main database. and if this subset consists of more records than can be displayed on one page. Then, when a pagination link is clicked to create another page of records, the [i][b]$_POST[/b][/i] array is returned empty and the values are not available to replicate the filtering.

Therefore the problem is to make the [i][b]$_POST[/b][/i] array values persistent.

My way of doing this is involves extending the session class with an adaption of the code posted in this thread [url=http://www.codeigniter.com/forus/viewthread/337/]http://www.codeigniter.com/forums/viewthread/337/[/url] by Kelvin Luck.

First, update your database with the following SQL: [code]ALTER TABLE ci_sessions ADD lastpost_data TEXT[/code]

then add the following code to the session class code (system/libraries/Session.php)

[code]// --------------------------------------------------------------------

// Code to facilitate transfer of $_POST array to and from session database // Based on code by Kelvin Luck published here http://www.codeigniter.com/forums/viewthread/337/

var $last_post;

/**

• Check if the $_POST global variable contains any data.

• if it does, copy it to the lastpost_data field in the sessions database.

• if it is empty, reload it with the last array .

• @author Dodmo

• @access public

• @param boolean

• @return void / function get_last_post($clear='TRUE'){ if ((count($_POST)==0)&&($this->_is_last_post())){ $_POST = $this->last_post; } else if (count($_POST)>0){ if($clear){ $last_post = array(); $this->set_last_post($_POST); } else{ $this->set_last_post($_POST); $_POST = $this->last_post; } } } /*

• Test for previous $_POST data stored in session database

• @author Dodmo

• @access private

• @return boolean */ function _is_last_post() { $this->_readlast_post(); $myresult = (count($this->last_post)>0) ; return $myresult; }

/**

• Fetch a specific item from the lastpost_data array in the session database

• (not required for get_last_post function but retained for future use.

• @authorKelvin Luck adapted by Dodmo

• @accesspublic

• @paramstring

• @returnstring */ function last_post($item) { if ($this->_readlast_post() ) { return ( ! isset($this->last_post[$item])) ? FALSE : $this->last_post[$item]; } else { return FALSE; } } // END last_post

/**

• Add or change data in the the lastpost_data array in the session database
• @authorKelvin Luck adapted by Dodmo
• @parammixed
• @paramstring
• @returnvoid */ function set_last_post($newdata = array(), $newval = '') { if ($this->_readlast_post()) { if (is_string($newdata)) { $newdata = array($newdata => $newval); }

if (count($newdata) > 0) { foreach ($newdata as $key => $val) { $this->last_post[$key] = $val; } }

$this->_writelast_post(); } } // END set_last_post

/**

• Internal function to read and unserialize the lastpost_data from the database
• @authorKelvin Luck adapted by Dodmo
• @accessprivate
• @returnboolean */ function _readlast_post(){ if ($this->use_database === TRUE) { if (!isset($this->last_post)) { $result = $this->object->db->query('SELECT lastpost_data FROM '.$this->session_table.' WHERE session_id=?', array($this->userdata['session_id'])); if ($result->num_rows() > 0) { $row = $result->row(); $session = $row->lastpost_data; if (count($session)>0){ $session = @unserialize($session); } if ($session == '') { $session = array(); } $this->last_post = $session; return TRUE; } else { log_message('error', '_readlast_post called when there is not a valid session in the database'); return FALSE; } } else { // already read it! return TRUE; } } else { log_message('error', 'You cannot access session->last_post unless you are using databases for your session!'); return FALSE; } } // END _readlast_post

/**

• Internal function to serialize and write the lastpost_data to the database
• @authorKelvin Luck adapted by Dodmo
• @accessprivate
• @returnvoid */ function _writelast_post() { $server_data_serialized = serialize($this->last_post); $this->object->db->query($this->object->db->update_string($this->session_table, array('lastpost_data' => $server_data_serialized), array('session_id' => $this->userdata['session_id']))); }

// END last_post

// End added code to facilitate transfer of $_POST array to and from session database [/code]

Now you have a new method you can call

[code] $this->session->get_last_post(); // (the parameter defaults to TRUE) [/code]

If [i][b]get_last_post()[/b][/i] is passed [i][b]TRUE[/b][/i] parameter or left void then the [i][b]lastpost_data[/b][/i] field in the sessions database will be cleared before the a new [i][b]$_POST[/b][/i] array is inserted ( [i][b]$_POST[/b][/i] is left unmodified) If the function is passed [i][b]FALSE[/b][/i] parameter then the existing [i][b]lastpost_data[/b][/i] will be amalgamated with the fresh [i][b]$_POST[/b][/i] data (exising keys are updated new ones added) and this amalgam is passed back into [i][b]$_POST[/b][/i] for the application to use.

[b]DISCLAIMER[/b] I am new to php/mysql and anyone using this code should bear that in mind.