DataConnector.php

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<?php

namespace ceLTIc\LTI\DataConnector;

use ceLTIc\LTI;
use ceLTIc\LTI\ConsumerNonce;
use ceLTIc\LTI\Context;
use ceLTIc\LTI\ResourceLink;
use ceLTIc\LTI\ResourceLinkShare;
use ceLTIc\LTI\ResourceLinkShareKey;
use ceLTIc\LTI\ToolConsumer;
use ceLTIc\LTI\UserResult;

class DataConnector
{

    const CONSUMER_TABLE_NAME = 'lti2_consumer';

    const CONTEXT_TABLE_NAME = 'lti2_context';

    const RESOURCE_LINK_TABLE_NAME = 'lti2_resource_link';

    const USER_RESULT_TABLE_NAME = 'lti2_user_result';

    const RESOURCE_LINK_SHARE_KEY_TABLE_NAME = 'lti2_share_key';

    const NONCE_TABLE_NAME = 'lti2_nonce';

    protected $db = null;

    protected $dbTableNamePrefix = '';

    protected $dateFormat = 'Y-m-d';

    protected $timeFormat = 'H:i:s';

    public function __construct($db, $dbTableNamePrefix = '')
    {
        $this->db = $db;
        $this->dbTableNamePrefix = $dbTableNamePrefix;
    }

###
###  ToolConsumer methods
###

    public function loadToolConsumer($consumer)
    {
        $consumer->secret = 'secret';
        $consumer->enabled = true;
        $now = time();
        $consumer->created = $now;
        $consumer->updated = $now;

        return true;
    }

    public function saveToolConsumer($consumer)
    {
        $consumer->updated = time();

        return true;
    }

    public function deleteToolConsumer($consumer)
    {
        $consumer->initialize();

        return true;
    }

    public function getToolConsumers()
    {
        return array();
    }

###
###  Context methods
###

    public function loadContext($context)
    {
        $now = time();
        $context->created = $now;
        $context->updated = $now;

        return true;
    }

    public function saveContext($context)
    {
        $context->updated = time();

        return true;
    }

    public function deleteContext($context)
    {
        $context->initialize();

        return true;
    }

###
###  ResourceLink methods
###

    public function loadResourceLink($resourceLink)
    {
        $now = time();
        $resourceLink->created = $now;
        $resourceLink->updated = $now;

        return true;
    }

    public function saveResourceLink($resourceLink)
    {
        $resourceLink->updated = time();

        return true;
    }

    public function deleteResourceLink($resourceLink)
    {
        $resourceLink->initialize();

        return true;
    }

    public function getUserResultSourcedIDsResourceLink($resourceLink, $localOnly, $idScope)
    {
        return array();
    }

    public function getSharesResourceLink($resourceLink)
    {
        return array();
    }

###
###  ConsumerNonce methods
###

    public function loadConsumerNonce($nonce)
    {
        return false;  // assume the nonce does not already exist
    }

    public function saveConsumerNonce($nonce)
    {
        return true;
    }

###
###  ResourceLinkShareKey methods
###

    public function loadResourceLinkShareKey($shareKey)
    {
        return true;
    }

    public function saveResourceLinkShareKey($shareKey)
    {
        return true;
    }

    public function deleteResourceLinkShareKey($shareKey)
    {
        return true;
    }

###
###  UserResult methods
###

    public function loadUserResult($userresult)
    {
        $now = time();
        $userresult->created = $now;
        $userresult->updated = $now;

        return true;
    }

    public function saveUserResult($userresult)
    {
        $userresult->updated = time();

        return true;
    }

    public function deleteUserResult($userresult)
    {
        $userresult->initialize();

        return true;
    }

###
###  Other methods
###

    public static function getDataConnector($db = null, $dbTableNamePrefix = '', $type = '')
    {
        if (is_null($dbTableNamePrefix)) {
            $dbTableNamePrefix = '';
        }
        if (!is_null($db) && empty($type)) {
            if (is_object($db)) {
                $type = get_class($db);
            } elseif (is_resource($db)) {
                $type = strtok(get_resource_type($db), ' ');
            }
        }
        $type = strtolower($type);
        if ($type === 'pdo') {
            if ($db->getAttribute(\PDO::ATTR_DRIVER_NAME) === 'pgsql') {
                $type .= '_pgsql';
            } elseif ($db->getAttribute(\PDO::ATTR_DRIVER_NAME) === 'oci') {
                $type .= '_oci';
            }
        }
        if (!empty($type)) {
            $type = "DataConnector_{$type}";
        } else {
            $type = 'DataConnector';
        }
        $type = "\\ceLTIc\\LTI\\DataConnector\\{$type}";
        $dataConnector = new $type($db, $dbTableNamePrefix);

        return $dataConnector;
    }

    public 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;
    }

    public function escape($value, $addQuotes = true)
    {
        return static::quoted($value, $addQuotes);
    }

    public static function quoted($value, $addQuotes = true)
    {
        if (is_null($value)) {
            $value = 'null';
        } else {
            $value = str_replace('\'', '\'\'', $value);
            if ($addQuotes) {
                $value = "'{$value}'";
            }
        }

        return $value;
    }

    protected static function getConsumerKey($key)
    {
        $len = strlen($key);
        if ($len > 255) {
            $key = 'sha512:' . hash('sha512', $key);
        }

        return $key;
    }

}