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Making POST array persistent
(Originally posted in this topic pagination and post variables)
If the values from the**$_POST**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 $_POSTarray is returned empty and the values are not available to replicate the filtering.
Therefore the problem is to make the $_POSTarray values persistent.
My way of doing this is involves extending the session class with an adaption of the code posted in this thread http://www.codeigniter.com/forums/viewthread/337/ by Kelvin Luck.
First, update your database with the following SQL:
ALTER TABLE `ci_sessions` ADD `lastpost_data` TEXTthen add the following code to the session class code (system/libraries/Session.php)
// -------------------------------------------------------------------- // 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 databaseNow you have a new method you can call
$this->session->get_last_post(); // (the parameter defaults to TRUE) Ifget_last_post()is passedTRUEparameter or left void then thelastpost_datafield in the sessions database will be cleared before the a new $_POSTarray is inserted ($_POSTis left unmodified) If the function is passed FALSEparameter then the existinglastpost_datawill be amalgamated with the fresh $_POSTdata (exising keys are updated new ones added) and this amalgam is passed back into $_POSTfor the application to use.
DISCLAIMER I am new to php/mysql and anyone using this code should bear that in mind.