575 lines
18 KiB
PHP
575 lines
18 KiB
PHP
<?php
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/**
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* ZeroBin
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*
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* a zero-knowledge paste bin
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*
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* @link http://sebsauvage.net/wiki/doku.php?id=php:zerobin
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* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
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* @license http://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
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* @version 0.19
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*/
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/**
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* zerobin
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*
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* Controller, puts it all together.
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*/
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class zerobin
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{
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/**
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* version
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*
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* @const string
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*/
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const VERSION = 'Alpha 0.19';
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/**
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* show the same error message if the paste expired or does not exist
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*
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* @const string
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*/
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const GENERIC_ERROR = 'Paste does not exist, has expired or has been deleted.';
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/**
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* configuration array
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*
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* @access private
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* @var array
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*/
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private $_conf = array(
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'model' => 'zerobin_data',
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);
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/**
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* data
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*
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* @access private
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* @var string
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*/
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private $_data = '';
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/**
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* error message
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*
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* @access private
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* @var string
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*/
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private $_error = '';
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/**
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* status message
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*
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* @access private
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* @var string
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*/
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private $_status = '';
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/**
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* data storage model
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*
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* @access private
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* @var zerobin_abstract
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*/
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private $_model;
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/**
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* constructor
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*
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* initializes and runs ZeroBin
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*
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* @access public
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* @return void
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*/
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public function __construct()
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{
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if (version_compare(PHP_VERSION, '5.2.6') < 0)
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throw new Exception('ZeroBin requires php 5.2.6 or above to work. Sorry.', 1);
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// in case stupid admin has left magic_quotes enabled in php.ini
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if (get_magic_quotes_gpc())
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{
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$_POST = array_map('filter::stripslashes_deep', $_POST);
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$_GET = array_map('filter::stripslashes_deep', $_GET);
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$_COOKIE = array_map('filter::stripslashes_deep', $_COOKIE);
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}
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// load config from ini file
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$this->_init();
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// create new paste or comment
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if (!empty($_POST['data']))
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{
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echo $this->_create($_POST['data']);
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return;
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}
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// delete an existing paste
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elseif (!empty($_GET['deletetoken']) && !empty($_GET['pasteid']))
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{
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$result = $this->_delete($_GET['pasteid'], $_GET['deletetoken']);
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if (strlen($result)) {
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echo $result;
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return;
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}
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}
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// display an existing paste
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elseif (!empty($_SERVER['QUERY_STRING']))
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{
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$this->_read($_SERVER['QUERY_STRING']);
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}
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// display ZeroBin frontend
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$this->_view();
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}
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/**
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* initialize zerobin
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*
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* @access private
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* @return void
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*/
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private function _init()
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{
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foreach (array('cfg', 'lib') as $dir)
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{
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if (!is_file(PATH . $dir . DIRECTORY_SEPARATOR . '.htaccess')) file_put_contents(
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PATH . $dir . DIRECTORY_SEPARATOR . '.htaccess',
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'Allow from none' . PHP_EOL .
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'Deny from all'. PHP_EOL,
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LOCK_EX
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);
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}
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$this->_conf = parse_ini_file(PATH . 'cfg' . DIRECTORY_SEPARATOR . 'conf.ini', true);
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foreach (array('main', 'model') as $section) {
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if (!array_key_exists($section, $this->_conf)) {
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throw new Exception("ZeroBin requires configuration section [$section] to be present in configuration file.", 2);
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}
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}
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$this->_model = $this->_conf['model']['class'];
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}
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/**
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* get the model, create one if needed
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*
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* @access private
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* @return zerobin_abstract
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*/
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private function _model()
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{
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// if needed, initialize the model
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if(is_string($this->_model)) {
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$this->_model = forward_static_call(
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array($this->_model, 'getInstance'),
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$this->_conf['model_options']
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);
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}
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return $this->_model;
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}
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/**
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* Store new paste or comment
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*
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* POST contains:
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* data (mandatory) = json encoded SJCL encrypted text (containing keys: iv,salt,ct)
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*
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* All optional data will go to meta information:
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* expire (optional) = expiration delay (never,5min,10min,1hour,1day,1week,1month,1year,burn) (default:never)
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* opendiscusssion (optional) = is the discussion allowed on this paste ? (0/1) (default:0)
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* nickname (optional) = in discussion, encoded SJCL encrypted text nickname of author of comment (containing keys: iv,salt,ct)
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* parentid (optional) = in discussion, which comment this comment replies to.
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* pasteid (optional) = in discussion, which paste this comment belongs to.
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*
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* @access private
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* @param string $data
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* @return string
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*/
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private function _create($data)
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{
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header('Content-type: application/json');
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$error = false;
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// Make sure last paste from the IP address was more than X seconds ago.
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trafficlimiter::setLimit($this->_conf['traffic']['limit']);
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trafficlimiter::setPath($this->_conf['traffic']['dir']);
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if (
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!trafficlimiter::canPass($_SERVER['REMOTE_ADDR'])
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) return $this->_return_message(
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1,
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'Please wait ' .
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$this->_conf['traffic']['limit'] .
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' seconds between each post.'
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);
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// Make sure content is not too big.
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$sizelimit = (int) $this->_getMainConfig('sizelimit', 2097152);
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if (
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strlen($data) > $sizelimit
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) return $this->_return_message(
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1,
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'Paste is limited to ' .
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filter::size_humanreadable($sizelimit) .
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' of encrypted data.'
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);
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// Make sure format is correct.
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if (!sjcl::isValid($data)) return $this->_return_message(1, 'Invalid data.');
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// Read additional meta-information.
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$meta=array();
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// Read expiration date
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if (!empty($_POST['expire']))
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{
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$selected_expire = (string) $_POST['expire'];
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if (array_key_exists($selected_expire, $this->_conf['expire_options'])) {
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$expire = $this->_conf['expire_options'][$selected_expire];
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} else {
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$expire = $this->_conf['expire_options'][$this->_conf['expire']['default']];
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}
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if ($expire > 0) $meta['expire_date'] = time() + $expire;
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}
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// Destroy the paste when it is read.
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if (!empty($_POST['burnafterreading']))
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{
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$burnafterreading = $_POST['burnafterreading'];
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if ($burnafterreading !== '0')
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{
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if ($burnafterreading !== '1') $error = true;
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$meta['burnafterreading'] = true;
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}
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}
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// Read open discussion flag.
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if ($this->_conf['main']['discussion'] && !empty($_POST['opendiscussion']))
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{
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$opendiscussion = $_POST['opendiscussion'];
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if ($opendiscussion !== '0')
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{
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if ($opendiscussion !== '1') $error = true;
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$meta['opendiscussion'] = true;
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}
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}
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// You can't have an open discussion on a "Burn after reading" paste:
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if (isset($meta['burnafterreading'])) unset($meta['opendiscussion']);
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// Optional nickname for comments
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if (!empty($_POST['nickname']))
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{
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// Generation of the anonymous avatar (Vizhash):
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// If a nickname is provided, we generate a Vizhash.
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// (We assume that if the user did not enter a nickname, he/she wants
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// to be anonymous and we will not generate the vizhash.)
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$nick = $_POST['nickname'];
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if (!sjcl::isValid($nick))
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{
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$error = true;
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}
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else
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{
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$meta['nickname'] = $nick;
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$vz = new vizhash16x16();
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$pngdata = $vz->generate($_SERVER['REMOTE_ADDR']);
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if ($pngdata != '')
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{
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$meta['vizhash'] = 'data:image/png;base64,' . base64_encode($pngdata);
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}
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// Once the avatar is generated, we do not keep the IP address, nor its hash.
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}
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}
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if ($error) return $this->_return_message(1, 'Invalid data.');
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// Add post date to meta.
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$meta['postdate'] = time();
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// We just want a small hash to avoid collisions:
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// Half-MD5 (64 bits) will do the trick
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$dataid = substr(hash('md5', $data), 0, 16);
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$storage = array('data' => $data);
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// Add meta-information only if necessary.
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if (count($meta)) $storage['meta'] = $meta;
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// The user posts a comment.
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if (
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!empty($_POST['parentid']) &&
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!empty($_POST['pasteid'])
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)
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{
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$pasteid = (string) $_POST['pasteid'];
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$parentid = (string) $_POST['parentid'];
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if (
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!filter::is_valid_paste_id($pasteid) ||
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!filter::is_valid_paste_id($parentid)
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) return $this->_return_message(1, 'Invalid data.');
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// Comments do not expire (it's the paste that expires)
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unset($storage['expire_date']);
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unset($storage['opendiscussion']);
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// Make sure paste exists.
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if (
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!$this->_model()->exists($pasteid)
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) return $this->_return_message(1, 'Invalid data.');
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// Make sure the discussion is opened in this paste.
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$paste = $this->_model()->read($pasteid);
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if (
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!$paste->meta->opendiscussion
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) return $this->_return_message(1, 'Invalid data.');
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// Check for improbable collision.
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if (
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$this->_model()->existsComment($pasteid, $parentid, $dataid)
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) return $this->_return_message(1, 'You are unlucky. Try again.');
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// New comment
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if (
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$this->_model()->createComment($pasteid, $parentid, $dataid, $storage) === false
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) return $this->_return_message(1, 'Error saving comment. Sorry.');
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// 0 = no error
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return $this->_return_message(0, $dataid);
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}
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// The user posts a standard paste.
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else
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{
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// Check for improbable collision.
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if (
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$this->_model()->exists($dataid)
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) return $this->_return_message(1, 'You are unlucky. Try again.');
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// New paste
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if (
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$this->_model()->create($dataid, $storage) === false
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) return $this->_return_message(1, 'Error saving paste. Sorry.');
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// Generate the "delete" token.
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// The token is the hmac of the pasteid signed with the server salt.
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// The paste can be delete by calling http://example.com/zerobin/?pasteid=<pasteid>&deletetoken=<deletetoken>
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$deletetoken = hash_hmac('sha1', $dataid, serversalt::get());
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// 0 = no error
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return $this->_return_message(0, $dataid, array('deletetoken' => $deletetoken));
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}
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return $this->_return_message(1, 'Server error.');
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}
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/**
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* Delete an existing paste
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*
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* @access private
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* @param string $dataid
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* @param string $deletetoken
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* @return string
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*/
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private function _delete($dataid, $deletetoken)
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{
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// Is this a valid paste identifier?
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if (!filter::is_valid_paste_id($dataid))
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{
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$this->_error = 'Invalid paste ID.';
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return '';
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}
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// Check that paste exists.
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if (!$this->_model()->exists($dataid))
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{
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$this->_error = self::GENERIC_ERROR;
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return '';
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}
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// Get the paste itself.
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$paste = $this->_model()->read($dataid);
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// See if paste has expired.
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if (
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isset($paste->meta->expire_date) &&
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$paste->meta->expire_date < time()
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)
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{
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// Delete the paste
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$this->_model()->delete($dataid);
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$this->_error = self::GENERIC_ERROR;
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}
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if ($deletetoken == 'burnafterreading') {
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header('Content-type: application/json');
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if (
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isset($paste->meta->burnafterreading) &&
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$paste->meta->burnafterreading
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)
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{
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// Delete the paste
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$this->_model()->delete($dataid);
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return $this->_return_message(0, 'Paste was properly deleted.');
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}
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return $this->_return_message(1, 'Paste is not of burn-after-reading type.');
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}
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// Make sure token is valid.
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serversalt::setPath($this->_conf['traffic']['dir']);
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if (!filter::slow_equals($deletetoken, hash_hmac('sha1', $dataid, serversalt::get())))
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{
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$this->_error = 'Wrong deletion token. Paste was not deleted.';
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return '';
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}
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// Paste exists and deletion token is valid: Delete the paste.
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$this->_model()->delete($dataid);
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$this->_status = 'Paste was properly deleted.';
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return '';
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}
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/**
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* Read an existing paste or comment
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*
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* @access private
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* @param string $dataid
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* @return void
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*/
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private function _read($dataid)
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{
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// Is this a valid paste identifier?
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if (!filter::is_valid_paste_id($dataid))
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{
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$this->_error = 'Invalid paste ID.';
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return;
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}
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// Check that paste exists.
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if ($this->_model()->exists($dataid))
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{
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// Get the paste itself.
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$paste = $this->_model()->read($dataid);
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// See if paste has expired.
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if (
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isset($paste->meta->expire_date) &&
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$paste->meta->expire_date < time()
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)
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{
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// Delete the paste
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$this->_model()->delete($dataid);
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$this->_error = self::GENERIC_ERROR;
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}
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// If no error, return the paste.
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else
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{
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// We kindly provide the remaining time before expiration (in seconds)
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if (
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property_exists($paste->meta, 'expire_date')
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) $paste->meta->remaining_time = $paste->meta->expire_date - time();
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// The paste itself is the first in the list of encrypted messages.
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$messages = array($paste);
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// If it's a discussion, get all comments.
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if (
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property_exists($paste->meta, 'opendiscussion') &&
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$paste->meta->opendiscussion
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)
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{
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$messages = array_merge(
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$messages,
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$this->_model()->readComments($dataid)
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);
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}
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$this->_data = json_encode($messages);
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}
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}
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else
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{
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$this->_error = self::GENERIC_ERROR;
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}
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}
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/**
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* Display ZeroBin frontend.
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*
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* @access private
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* @return void
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*/
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private function _view()
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{
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// set headers to disable caching
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$time = gmdate('D, d M Y H:i:s \G\M\T');
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header('Cache-Control: no-store, no-cache, must-revalidate');
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header('Pragma: no-cache');
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header('Expires: ' . $time);
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header('Last-Modified: ' . $time);
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header('Vary: Accept');
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// label all the expiration options
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$expire = array();
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foreach ($this->_conf['expire_options'] as $key => $value) {
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$expire[$key] = array_key_exists($key, $this->_conf['expire_labels']) ?
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$this->_conf['expire_labels'][$key] :
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$key;
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}
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$page = new RainTPL;
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$page::$path_replace = false;
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// we escape it here because ENT_NOQUOTES can't be used in RainTPL templates
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$page->assign('CIPHERDATA', htmlspecialchars($this->_data, ENT_NOQUOTES));
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$page->assign('ERROR', $this->_error);
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$page->assign('STATUS', $this->_status);
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$page->assign('VERSION', self::VERSION);
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$page->assign('DISCUSSION', $this->_getMainConfig('discussion', true));
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$page->assign('OPENDISCUSSION', $this->_getMainConfig('opendiscussion', true));
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$page->assign('SYNTAXHIGHLIGHTING', $this->_getMainConfig('syntaxhighlighting', true));
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$page->assign('SYNTAXHIGHLIGHTINGTHEME', $this->_getMainConfig('syntaxhighlightingtheme', ''));
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$page->assign('NOTICE', $this->_getMainConfig('notice', ''));
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$page->assign('BURNAFTERREADINGSELECTED', $this->_getMainConfig('burnafterreadingselected', false));
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$page->assign('PASSWORD', $this->_getMainConfig('password', true));
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$page->assign('BASE64JSVERSION', $this->_getMainConfig('base64version', '2.1.9'));
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$page->assign('EXPIRE', $expire);
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$page->assign('EXPIREDEFAULT', $this->_conf['expire']['default']);
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$page->draw($this->_getMainConfig('template', 'page'));
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}
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/**
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* get configuration option from [main] section, optionally set a default
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*
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* @access private
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* @param string $option
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* @param mixed $default (optional)
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* @return mixed
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*/
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private function _getMainConfig($option, $default = false)
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{
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return array_key_exists($option, $this->_conf['main']) ?
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$this->_conf['main'][$option] :
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$default;
|
|
}
|
|
|
|
/**
|
|
* return JSON encoded message and exit
|
|
*
|
|
* @access private
|
|
* @param bool $status
|
|
* @param string $message
|
|
* @param array $other
|
|
* @return string
|
|
*/
|
|
private function _return_message($status, $message, $other = array())
|
|
{
|
|
$result = array('status' => $status);
|
|
if ($status)
|
|
{
|
|
$result['message'] = $message;
|
|
}
|
|
else
|
|
{
|
|
$result['id'] = $message;
|
|
}
|
|
$result += $other;
|
|
return json_encode($result);
|
|
}
|
|
}
|