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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This is the external API for generic xAPI handling.
*
* @package core_xapi
* @since Moodle 3.9
* @copyright 2020 Ferran Recio
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core_xapi\external;
use core_xapi\local\statement;
use core_xapi\handler;
use core_xapi\xapi_exception;
use external_api;
use external_function_parameters;
use external_value;
use external_single_structure;
use external_multiple_structure;
use external_warnings;
use core_component;
defined('MOODLE_INTERNAL') || die();
require_once($CFG->libdir .'/externallib.php');
/**
* This is the external API for generic xAPI handling.
*
* @copyright 2020 Ferran Recio
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class post_statement extends external_api {
/**
* Parameters for execute
*
* @return external_function_parameters
*/
public static function execute_parameters() {
return new external_function_parameters(
[
'component' => new external_value(PARAM_COMPONENT, 'Component name', VALUE_REQUIRED),
'requestjson' => new external_value(PARAM_RAW, 'json object with all the statements to post', VALUE_REQUIRED)
]
);
}
/**
* Process a statement post request.
*
* @param string $component component name (frankenstyle)
* @param string $requestjson json object with all the statements to post
* @return bool[] storing acceptance of every statement
*/
public static function execute(string $component, string $requestjson): array {
$params = self::validate_parameters(self::execute_parameters(), array(
'component' => $component,
'requestjson' => $requestjson,
));
$component = $params['component'];
$requestjson = $params['requestjson'];
static::validate_component($component);
$handler = handler::create($component);
$statements = self::get_statements_from_json($requestjson);
if (!self::check_statements_users($statements, $handler)) {
throw new xapi_exception('Statements actor is not the current user');
}
$result = $handler->process_statements($statements);
// In case no statement is processed, an error must be returned.
if (count(array_filter($result)) == 0) {
throw new xapi_exception('No statement can be processed.');
}
return $result;
}
/**
* Return for execute.
*/
public static function execute_returns() {
return new external_multiple_structure(
new external_value(PARAM_BOOL, 'If the statement is accepted'),
'List of statements storing acceptance results'
);
}
/**
* Check component name.
*
* Note: this function is separated mainly for testing purposes to
* be overridden to fake components.
*
* @throws xapi_exception if component is not available
* @param string $component component name
*/
protected static function validate_component(string $component): void {
// Check that $component is a real component name.
$dir = core_component::get_component_directory($component);
if (!$dir) {
throw new xapi_exception("Component $component not available.");
}
}
/**
* Convert mulitple types of statement request into an array of statements.
*
* @throws xapi_exception if JSON cannot be parsed
* @param string $requestjson json encoded statements structure
* @return statement[] array of statements
*/
private static function get_statements_from_json(string $requestjson): array {
$request = json_decode($requestjson);
if ($request === null) {
throw new xapi_exception('JSON error: '.json_last_error_msg());
}
$result = [];
if (is_array($request)) {
foreach ($request as $data) {
$result[] = statement::create_from_data($data);
}
} else {
$result[] = statement::create_from_data($request);
}
if (empty($result)) {
throw new xapi_exception('No statements detected');
}
return $result;
}
/**
* Check that $USER is actor in all statements.
*
* @param statement[] $statements array of statements
* @param handler $handler specific xAPI handler
* @return bool if $USER is actor in all statements
*/
private static function check_statements_users(array $statements, handler $handler): bool {
global $USER;
foreach ($statements as $statement) {
if ($handler->supports_group_actors()) {
$users = $statement->get_all_users();
if (!isset($users[$USER->id])) {
return false;
}
} else {
$user = $statement->get_user();
if ($user->id != $USER->id) {
return false;
}
}
}
return true;
}
}