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<?php
namespace IMSGlobal\LTI\ToolProvider\DataConnector;
use IMSGlobal\LTI\ToolProvider\ConsumerNonce;
use IMSGlobal\LTI\ToolProvider\Context;
use IMSGlobal\LTI\ToolProvider\ResourceLink;
use IMSGlobal\LTI\ToolProvider\ResourceLinkShareKey;
use IMSGlobal\LTI\ToolProvider\ToolConsumer;
use IMSGlobal\LTI\ToolProvider\ToolProxy;
use IMSGlobal\LTI\ToolProvider\User;
use PDO;
/**
* Class to provide a connection to a persistent store for LTI objects
*
* This class assumes no data persistence - it should be extended for specific database connections.
*
* @author Stephen P Vickers <svickers@imsglobal.org>
* @copyright IMS Global Learning Consortium Inc
* @date 2016
* @version 3.0.0
* @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
*/
class DataConnector
{
/**
* Default name for database table used to store tool consumers.
*/
const CONSUMER_TABLE_NAME = 'lti2_consumer';
/**
* Default name for database table used to store pending tool proxies.
*/
const TOOL_PROXY_TABLE_NAME = 'lti2_tool_proxy';
/**
* Default name for database table used to store contexts.
*/
const CONTEXT_TABLE_NAME = 'lti2_context';
/**
* Default name for database table used to store resource links.
*/
const RESOURCE_LINK_TABLE_NAME = 'lti2_resource_link';
/**
* Default name for database table used to store users.
*/
const USER_RESULT_TABLE_NAME = 'lti2_user_result';
/**
* Default name for database table used to store resource link share keys.
*/
const RESOURCE_LINK_SHARE_KEY_TABLE_NAME = 'lti2_share_key';
/**
* Default name for database table used to store nonce values.
*/
const NONCE_TABLE_NAME = 'lti2_nonce';
/**
* Database object.
*
* @var object $db
*/
protected $db = null;
/**
* Prefix for database table names.
*
* @var string $dbTableNamePrefix
*/
protected $dbTableNamePrefix = '';
/**
* SQL date format (default = 'Y-m-d')
*
* @var string $dateFormat
*/
protected $dateFormat = 'Y-m-d';
/**
* SQL time format (default = 'H:i:s')
*
* @var string $timeFormat
*/
protected $timeFormat = 'H:i:s';
/**
* Class constructor
*
* @param object $db Database connection object
* @param string $dbTableNamePrefix Prefix for database table names (optional, default is none)
*/
public function __construct($db, $dbTableNamePrefix = '')
{
$this->db = $db;
$this->dbTableNamePrefix = $dbTableNamePrefix;
}
###
### ToolConsumer methods
###
/**
* Load tool consumer object.
*
* @param ToolConsumer $consumer ToolConsumer object
*
* @return boolean True if the tool consumer object was successfully loaded
*/
public function loadToolConsumer($consumer)
{
$consumer->secret = 'secret';
$consumer->enabled = true;
$now = time();
$consumer->created = $now;
$consumer->updated = $now;
return true;
}
/**
* Save tool consumer object.
*
* @param ToolConsumer $consumer Consumer object
*
* @return boolean True if the tool consumer object was successfully saved
*/
public function saveToolConsumer($consumer)
{
$consumer->updated = time();
return true;
}
/**
* Delete tool consumer object.
*
* @param ToolConsumer $consumer Consumer object
*
* @return boolean True if the tool consumer object was successfully deleted
*/
public function deleteToolConsumer($consumer)
{
$consumer->initialize();
return true;
}
/**
* Load tool consumer objects.
*
* @return array Array of all defined ToolConsumer objects
*/
public function getToolConsumers()
{
return array();
}
###
### ToolProxy methods
###
/**
* Load tool proxy object.
*
* @param ToolProxy $toolProxy ToolProxy object
*
* @return boolean True if the tool proxy object was successfully loaded
*/
public function loadToolProxy($toolProxy)
{
$now = time();
$toolProxy->created = $now;
$toolProxy->updated = $now;
return true;
}
/**
* Save tool proxy object.
*
* @param ToolProxy $toolProxy ToolProxy object
*
* @return boolean True if the tool proxy object was successfully saved
*/
public function saveToolProxy($toolProxy)
{
$toolProxy->updated = time();
return true;
}
/**
* Delete tool proxy object.
*
* @param ToolProxy $toolProxy ToolProxy object
*
* @return boolean True if the tool proxy object was successfully deleted
*/
public function deleteToolProxy($toolProxy)
{
$toolProxy->initialize();
return true;
}
###
### Context methods
###
/**
* Load context object.
*
* @param Context $context Context object
*
* @return boolean True if the context object was successfully loaded
*/
public function loadContext($context)
{
$now = time();
$context->created = $now;
$context->updated = $now;
return true;
}
/**
* Save context object.
*
* @param Context $context Context object
*
* @return boolean True if the context object was successfully saved
*/
public function saveContext($context)
{
$context->updated = time();
return true;
}
/**
* Delete context object.
*
* @param Context $context Context object
*
* @return boolean True if the Context object was successfully deleted
*/
public function deleteContext($context)
{
$context->initialize();
return true;
}
###
### ResourceLink methods
###
/**
* Load resource link object.
*
* @param ResourceLink $resourceLink Resource_Link object
*
* @return boolean True if the resource link object was successfully loaded
*/
public function loadResourceLink($resourceLink)
{
$now = time();
$resourceLink->created = $now;
$resourceLink->updated = $now;
return true;
}
/**
* Save resource link object.
*
* @param ResourceLink $resourceLink Resource_Link object
*
* @return boolean True if the resource link object was successfully saved
*/
public function saveResourceLink($resourceLink)
{
$resourceLink->updated = time();
return true;
}
/**
* Delete resource link object.
*
* @param ResourceLink $resourceLink Resource_Link object
*
* @return boolean True if the resource link object was successfully deleted
*/
public function deleteResourceLink($resourceLink)
{
$resourceLink->initialize();
return true;
}
/**
* Get array of user objects.
*
* Obtain an array of User objects for users with a result sourcedId. The array may include users from other
* resource links which are sharing this resource link. It may also be optionally indexed by the user ID of a specified scope.
*
* @param ResourceLink $resourceLink Resource link object
* @param boolean $localOnly True if only users within the resource link are to be returned (excluding users sharing this resource link)
* @param int $idScope Scope value to use for user IDs
*
* @return array Array of User objects
*/
public function getUserResultSourcedIDsResourceLink($resourceLink, $localOnly, $idScope)
{
return array();
}
/**
* Get array of shares defined for this resource link.
*
* @param ResourceLink $resourceLink Resource_Link object
*
* @return array Array of ResourceLinkShare objects
*/
public function getSharesResourceLink($resourceLink)
{
return array();
}
###
### ConsumerNonce methods
###
/**
* Load nonce object.
*
* @param ConsumerNonce $nonce Nonce object
*
* @return boolean True if the nonce object was successfully loaded
*/
public function loadConsumerNonce($nonce)
{
return false; // assume the nonce does not already exist
}
/**
* Save nonce object.
*
* @param ConsumerNonce $nonce Nonce object
*
* @return boolean True if the nonce object was successfully saved
*/
public function saveConsumerNonce($nonce)
{
return true;
}
###
### ResourceLinkShareKey methods
###
/**
* Load resource link share key object.
*
* @param ResourceLinkShareKey $shareKey Resource_Link share key object
*
* @return boolean True if the resource link share key object was successfully loaded
*/
public function loadResourceLinkShareKey($shareKey)
{
return true;
}
/**
* Save resource link share key object.
*
* @param ResourceLinkShareKey $shareKey Resource link share key object
*
* @return boolean True if the resource link share key object was successfully saved
*/
public function saveResourceLinkShareKey($shareKey)
{
return true;
}
/**
* Delete resource link share key object.
*
* @param ResourceLinkShareKey $shareKey Resource link share key object
*
* @return boolean True if the resource link share key object was successfully deleted
*/
public function deleteResourceLinkShareKey($shareKey)
{
return true;
}
###
### User methods
###
/**
* Load user object.
*
* @param User $user User object
*
* @return boolean True if the user object was successfully loaded
*/
public function loadUser($user)
{
$now = time();
$user->created = $now;
$user->updated = $now;
return true;
}
/**
* Save user object.
*
* @param User $user User object
*
* @return boolean True if the user object was successfully saved
*/
public function saveUser($user)
{
$user->updated = time();
return true;
}
/**
* Delete user object.
*
* @param User $user User object
*
* @return boolean True if the user object was successfully deleted
*/
public function deleteUser($user)
{
$user->initialize();
return true;
}
###
### Other methods
###
/**
* Return a hash of a consumer key for values longer than 255 characters.
*
* @param string $key
* @return string
*/
protected static function getConsumerKey($key)
{
$len = strlen($key);
if ($len > 255) {
$key = 'sha512:' . hash('sha512', $key);
}
return $key;
}
/**
* Create data connector object.
*
* A data connector provides access to persistent storage for the different objects.
*
* Names of tables may be given a prefix to allow multiple versions to share the same schema. A separate sub-class is defined for
* each different database connection - the class to use is determined by inspecting the database object passed, but this can be overridden
* (for example, to use a bespoke connector) by specifying a type. If no database is passed then this class is used which acts as a dummy
* connector with no persistence.
*
* @param string $dbTableNamePrefix Prefix for database table names (optional, default is none)
* @param object $db A database connection object or string (optional, default is no persistence)
* @param string $type The type of data connector (optional, default is based on $db parameter)
*
* @return DataConnector Data connector object
*/
public static function getDataConnector($dbTableNamePrefix = '', $db = null, $type = '')
{
if (is_null($dbTableNamePrefix)) {
$dbTableNamePrefix = '';
}
if (!is_null($db) && empty($type)) {
if (is_object($db)) {
$type = get_class($db);
}
}
$type = strtolower($type);
if (($type === 'pdo') && ($db->getAttribute(PDO::ATTR_DRIVER_NAME) === 'sqlite')) {
$type .= '_sqlite';
}
if (!empty($type)) {
$type ="DataConnector_{$type}";
} else {
$type ='DataConnector';
}
$type = "\\IMSGlobal\\LTI\\ToolProvider\\DataConnector\\{$type}";
$dataConnector = new $type($db, $dbTableNamePrefix);
return $dataConnector;
}
/**
* Generate a random string.
*
* The generated string will only comprise letters (upper- and lower-case) and digits.
*
* @param int $length Length of string to be generated (optional, default is 8 characters)
*
* @return string Random string
*/
static function getRandomString($length = 8)
{
$chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
$value = '';
$charsLength = strlen($chars) - 1;
for ($i = 1 ; $i <= $length; $i++) {
$value .= $chars[rand(0, $charsLength)];
}
return $value;
}
/**
* Quote a string for use in a database query.
*
* Any single quotes in the value passed will be replaced with two single quotes. If a null value is passed, a string
* of 'null' is returned (which will never be enclosed in quotes irrespective of the value of the $addQuotes parameter.
*
* @param string $value Value to be quoted
* @param bool $addQuotes If true the returned string will be enclosed in single quotes (optional, default is true)
* @return string The quoted string.
*/
static function quoted($value, $addQuotes = true)
{
if (is_null($value)) {
$value = 'null';
} else {
$value = str_replace('\'', '\'\'', $value);
if ($addQuotes) {
$value = "'{$value}'";
}
}
return $value;
}
}