moodle/lib/external/classes/external_api.php

587 lines
26 KiB
PHP

<?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/>.
namespace core_external;
use coding_exception;
use context;
use context_helper;
use context_system;
use core_component;
use core_php_time_limit;
use invalid_parameter_exception;
use invalid_response_exception;
use moodle_exception;
/**
* Base class for external api methods.
*
* @package core_webservice
* @copyright 2009 Petr Skodak
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
* @since Moodle 2.0
*/
class external_api {
/** @var \stdClass context where the function calls will be restricted */
private static $contextrestriction;
/**
* Returns detailed function information
*
* @param string|\stdClass $function name of external function or record from external_function
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* MUST_EXIST means throw exception if no record or multiple records found
* @return \stdClass|bool description or false if not found or exception thrown
* @throws coding_exception for any property and/or method that is missing or invalid
* @since Moodle 2.0
*/
public static function external_function_info($function, $strictness = MUST_EXIST) {
global $DB, $CFG;
if (!is_object($function)) {
if (!$function = $DB->get_record('external_functions', ['name' => $function], '*', $strictness)) {
return false;
}
}
// First try class autoloading.
if (!class_exists($function->classname)) {
// Fallback to explicit include of externallib.php.
if (empty($function->classpath)) {
$function->classpath = core_component::get_component_directory($function->component) . '/externallib.php';
} else {
$function->classpath = "{$CFG->dirroot}/{$function->classpath}";
}
if (!file_exists($function->classpath)) {
throw new coding_exception(
"Cannot find file {$function->classpath} with external function implementation " .
"for {$function->classname}::{$function->methodname}"
);
}
require_once($function->classpath);
if (!class_exists($function->classname)) {
throw new coding_exception("Cannot find external class {$function->classname}");
}
}
$function->ajax_method = "{$function->methodname}_is_allowed_from_ajax";
$function->parameters_method = "{$function->methodname}_parameters";
$function->returns_method = "{$function->methodname}_returns";
$function->deprecated_method = "{$function->methodname}_is_deprecated";
// Make sure the implementaion class is ok.
if (!method_exists($function->classname, $function->methodname)) {
throw new coding_exception(
"Missing implementation method {$function->classname}::{$function->methodname}"
);
}
if (!method_exists($function->classname, $function->parameters_method)) {
throw new coding_exception(
"Missing parameters description method {$function->classname}::{$function->parameters_method}"
);
}
if (!method_exists($function->classname, $function->returns_method)) {
throw new coding_exception(
"Missing returned values description method {$function->classname}::{$function->returns_method}"
);
}
if (method_exists($function->classname, $function->deprecated_method)) {
if (call_user_func([$function->classname, $function->deprecated_method]) === true) {
$function->deprecated = true;
}
}
$function->allowed_from_ajax = false;
// Fetch the parameters description.
$function->parameters_desc = call_user_func([$function->classname, $function->parameters_method]);
if (!($function->parameters_desc instanceof external_function_parameters)) {
throw new coding_exception(
"{$function->classname}::{$function->parameters_method} did not return a valid external_function_parameters object"
);
}
// Fetch the return values description.
$function->returns_desc = call_user_func([$function->classname, $function->returns_method]);
// Null means void result or result is ignored.
if (!is_null($function->returns_desc) && !($function->returns_desc instanceof external_description)) {
throw new coding_exception(
"{$function->classname}::{$function->returns_method} did not return a valid external_description object"
);
}
// Now get the function description.
// TODO MDL-31115 use localised lang pack descriptions, it would be nice to have
// easy to understand descriptions in admin UI,
// on the other hand this is still a bit in a flux and we need to find some new naming
// conventions for these descriptions in lang packs.
$function->description = null;
$servicesfile = core_component::get_component_directory($function->component) . '/db/services.php';
if (file_exists($servicesfile)) {
$functions = null;
include($servicesfile);
if (isset($functions[$function->name]['description'])) {
$function->description = $functions[$function->name]['description'];
}
if (isset($functions[$function->name]['testclientpath'])) {
$function->testclientpath = $functions[$function->name]['testclientpath'];
}
if (isset($functions[$function->name]['type'])) {
$function->type = $functions[$function->name]['type'];
}
if (isset($functions[$function->name]['ajax'])) {
$function->allowed_from_ajax = $functions[$function->name]['ajax'];
} else if (method_exists($function->classname, $function->ajax_method)) {
if (call_user_func([$function->classname, $function->ajax_method]) === true) {
debugging('External function ' . $function->ajax_method . '() function is deprecated.' .
'Set ajax=>true in db/service.php instead.', DEBUG_DEVELOPER);
$function->allowed_from_ajax = true;
}
}
if (isset($functions[$function->name]['loginrequired'])) {
$function->loginrequired = $functions[$function->name]['loginrequired'];
} else {
$function->loginrequired = true;
}
if (isset($functions[$function->name]['readonlysession'])) {
$function->readonlysession = $functions[$function->name]['readonlysession'];
} else {
$function->readonlysession = false;
}
}
return $function;
}
/**
* Call an external function validating all params/returns correctly.
*
* Note that an external function may modify the state of the current page, so this wrapper
* saves and restores tha PAGE and COURSE global variables before/after calling the external function.
*
* @param string $function A webservice function name.
* @param array $args Params array (named params)
* @param boolean $ajaxonly If true, an extra check will be peformed to see if ajax is required.
* @return array containing keys for error (bool), exception and data.
*/
public static function call_external_function($function, $args, $ajaxonly = false) {
global $PAGE, $COURSE, $CFG, $SITE;
require_once("{$CFG->libdir}/pagelib.php");
$externalfunctioninfo = static::external_function_info($function);
// Eventually this should shift into the various handlers and not be handled via config.
$readonlysession = $externalfunctioninfo->readonlysession ?? false;
if (!$readonlysession || empty($CFG->enable_read_only_sessions)) {
\core\session\manager::restart_with_write_lock($readonlysession);
}
$currentpage = $PAGE;
$currentcourse = $COURSE;
$response = [];
try {
// Taken straight from from setup.php.
if (!empty($CFG->moodlepageclass)) {
if (!empty($CFG->moodlepageclassfile)) {
require_once($CFG->moodlepageclassfile);
}
$classname = $CFG->moodlepageclass;
} else {
$classname = 'moodle_page';
}
$PAGE = new $classname();
$COURSE = clone($SITE);
if ($ajaxonly && !$externalfunctioninfo->allowed_from_ajax) {
throw new moodle_exception('servicenotavailable', 'webservice');
}
// Do not allow access to write or delete webservices as a public user.
if ($externalfunctioninfo->loginrequired && !WS_SERVER) {
if (defined('NO_MOODLE_COOKIES') && NO_MOODLE_COOKIES && !PHPUNIT_TEST) {
throw new moodle_exception('servicerequireslogin', 'webservice');
}
if (!isloggedin()) {
throw new moodle_exception('servicerequireslogin', 'webservice');
} else {
require_sesskey();
}
}
// Validate params, this also sorts the params properly, we need the correct order in the next part.
$callable = [$externalfunctioninfo->classname, 'validate_parameters'];
$params = call_user_func(
$callable,
$externalfunctioninfo->parameters_desc,
$args
);
$params = array_values($params);
// Allow any Moodle plugin a chance to override this call. This is a convenient spot to
// make arbitrary behaviour customisations. The overriding plugin could call the 'real'
// function first and then modify the results, or it could do a completely separate
// thing.
$callbacks = get_plugins_with_function('override_webservice_execution');
$result = false;
foreach (array_values($callbacks) as $plugins) {
foreach (array_values($plugins) as $callback) {
$result = $callback($externalfunctioninfo, $params);
if ($result !== false) {
break 2;
}
}
}
// If the function was not overridden, call the real one.
if ($result === false) {
$callable = [$externalfunctioninfo->classname, $externalfunctioninfo->methodname];
$result = call_user_func_array($callable, $params);
}
// Validate the return parameters.
if ($externalfunctioninfo->returns_desc !== null) {
$callable = [$externalfunctioninfo->classname, 'clean_returnvalue'];
$result = call_user_func($callable, $externalfunctioninfo->returns_desc, $result);
}
$response['error'] = false;
$response['data'] = $result;
} catch (\Throwable $e) {
$exception = get_exception_info($e);
unset($exception->a);
$exception->backtrace = format_backtrace($exception->backtrace, true);
if (!debugging('', DEBUG_DEVELOPER)) {
unset($exception->debuginfo);
unset($exception->backtrace);
}
$response['error'] = true;
$response['exception'] = $exception;
// Do not process the remaining requests.
}
$PAGE = $currentpage;
$COURSE = $currentcourse;
return $response;
}
/**
* Set context restriction for all following subsequent function calls.
*
* @param \stdClass $context the context restriction
* @since Moodle 2.0
*/
public static function set_context_restriction($context) {
self::$contextrestriction = $context;
}
/**
* This method has to be called before every operation
* that takes a longer time to finish!
*
* @param int $seconds max expected time the next operation needs
* @since Moodle 2.0
*/
public static function set_timeout($seconds = 360) {
$seconds = ($seconds < 300) ? 300 : $seconds;
core_php_time_limit::raise($seconds);
}
/**
* Validates submitted function parameters, if anything is incorrect
* invalid_parameter_exception is thrown.
* This is a simple recursive method which is intended to be called from
* each implementation method of external API.
*
* @param external_description $description description of parameters
* @param mixed $params the actual parameters
* @return mixed params with added defaults for optional items, invalid_parameters_exception thrown if any problem found
* @since Moodle 2.0
*/
public static function validate_parameters(external_description $description, $params) {
if ($params === null && $description->allownull == NULL_ALLOWED) {
return null;
}
if ($description instanceof external_value) {
if (is_array($params) || is_object($params)) {
throw new invalid_parameter_exception('Scalar type expected, array or object received.');
}
if ($description->type == PARAM_BOOL) {
// Special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here.
if (is_bool($params) || $params === 0 || $params === 1 || $params === '0' || $params === '1') {
return (bool) $params;
}
}
$debuginfo = "Invalid external api parameter: the value is \"{$params}\", ";
$debuginfo .= "the server was expecting \"{$description->type}\" type";
return validate_param($params, $description->type, $description->allownull, $debuginfo);
} else if ($description instanceof external_single_structure) {
if (!is_array($params)) {
throw new invalid_parameter_exception(
// phpcs:ignore moodle.PHP.ForbiddenFunctions.Found
"Only arrays accepted. The bad value is: '" . print_r($params, true) . "'"
);
}
$result = [];
foreach ($description->keys as $key => $subdesc) {
if (!array_key_exists($key, $params)) {
if ($subdesc->required == VALUE_REQUIRED) {
throw new invalid_parameter_exception("Missing required key in single structure: {$key}");
}
if ($subdesc->required == VALUE_DEFAULT) {
try {
$result[$key] = static::validate_parameters($subdesc, $subdesc->default);
} catch (invalid_parameter_exception $e) {
// We are only interested by exceptions returned by validate_param() and validate_parameters().
// This is used to build the path to the faulty attribute.
throw new invalid_parameter_exception("{$key} => " . $e->getMessage() . ': ' . $e->debuginfo);
}
}
} else {
try {
$result[$key] = static::validate_parameters($subdesc, $params[$key]);
} catch (invalid_parameter_exception $e) {
// We are only interested by exceptions returned by validate_param() and validate_parameters().
// This is used to build the path to the faulty attribute.
throw new invalid_parameter_exception($key . " => " . $e->getMessage() . ': ' . $e->debuginfo);
}
}
unset($params[$key]);
}
if (!empty($params)) {
throw new invalid_parameter_exception(
'Unexpected keys (' . implode(', ', array_keys($params)) . ') detected in parameter array.'
);
}
return $result;
} else if ($description instanceof external_multiple_structure) {
if (!is_array($params)) {
throw new invalid_parameter_exception(
'Only arrays accepted. The bad value is: \'' .
// phpcs:ignore moodle.PHP.ForbiddenFunctions.Found
print_r($params, true) .
"'"
);
}
$result = [];
foreach ($params as $param) {
$result[] = static::validate_parameters($description->content, $param);
}
return $result;
} else {
throw new invalid_parameter_exception('Invalid external api description');
}
}
/**
* Clean response
* If a response attribute is unknown from the description, we just ignore the attribute.
* If a response attribute is incorrect, invalid_response_exception is thrown.
* Note: this function is similar to validate parameters, however it is distinct because
* parameters validation must be distinct from cleaning return values.
*
* @param external_description $description description of the return values
* @param mixed $response the actual response
* @return mixed response with added defaults for optional items, invalid_response_exception thrown if any problem found
* @author 2010 Jerome Mouneyrac
* @since Moodle 2.0
*/
public static function clean_returnvalue(external_description $description, $response) {
if ($response === null && $description->allownull == NULL_ALLOWED) {
return null;
}
if ($description instanceof external_value) {
if (is_array($response) || is_object($response)) {
throw new invalid_response_exception('Scalar type expected, array or object received.');
}
if ($description->type == PARAM_BOOL) {
// Special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here.
if (is_bool($response) || $response === 0 || $response === 1 || $response === '0' || $response === '1') {
return (bool) $response;
}
}
$responsetype = gettype($response);
$debuginfo = "Invalid external api response: the value is \"{$response}\" of PHP type \"{$responsetype}\", ";
$debuginfo .= "the server was expecting \"{$description->type}\" type";
try {
return validate_param($response, $description->type, $description->allownull, $debuginfo);
} catch (invalid_parameter_exception $e) {
// Proper exception name, to be recursively catched to build the path to the faulty attribute.
throw new invalid_response_exception($e->debuginfo);
}
} else if ($description instanceof external_single_structure) {
if (!is_array($response) && !is_object($response)) {
throw new invalid_response_exception(
// phpcs:ignore moodle.PHP.ForbiddenFunctions.Found
"Only arrays/objects accepted. The bad value is: '" . print_r($response, true) . "'"
);
}
// Cast objects into arrays.
if (is_object($response)) {
$response = (array) $response;
}
$result = [];
foreach ($description->keys as $key => $subdesc) {
if (!array_key_exists($key, $response)) {
if ($subdesc->required == VALUE_REQUIRED) {
throw new invalid_response_exception(
"Error in response - Missing following required key in a single structure: {$key}"
);
}
if ($subdesc instanceof external_value) {
if ($subdesc->required == VALUE_DEFAULT) {
try {
$result[$key] = static::clean_returnvalue($subdesc, $subdesc->default);
} catch (invalid_response_exception $e) {
// Build the path to the faulty attribute.
throw new invalid_response_exception("{$key} => " . $e->getMessage() . ': ' . $e->debuginfo);
}
}
}
} else {
try {
$result[$key] = static::clean_returnvalue($subdesc, $response[$key]);
} catch (invalid_response_exception $e) {
// Build the path to the faulty attribute.
throw new invalid_response_exception("{$key} => " . $e->getMessage() . ': ' . $e->debuginfo);
}
}
unset($response[$key]);
}
return $result;
} else if ($description instanceof external_multiple_structure) {
if (!is_array($response)) {
throw new invalid_response_exception(
// phpcs:ignore moodle.PHP.ForbiddenFunctions.Found
"Only arrays accepted. The bad value is: '" . print_r($response, true) . "'"
);
}
$result = [];
foreach ($response as $param) {
$result[] = static::clean_returnvalue($description->content, $param);
}
return $result;
} else {
throw new invalid_response_exception('Invalid external api response description');
}
}
/**
* Makes sure user may execute functions in this context.
*
* @param context $context
* @since Moodle 2.0
*/
public static function validate_context($context) {
global $PAGE;
if (empty($context)) {
throw new invalid_parameter_exception('Context does not exist');
}
if (empty(self::$contextrestriction)) {
self::$contextrestriction = context_system::instance();
}
$rcontext = self::$contextrestriction;
if ($rcontext->contextlevel == $context->contextlevel) {
if ($rcontext->id != $context->id) {
throw new restricted_context_exception();
}
} else if ($rcontext->contextlevel > $context->contextlevel) {
throw new restricted_context_exception();
} else {
$parents = $context->get_parent_context_ids();
if (!in_array($rcontext->id, $parents)) {
throw new restricted_context_exception();
}
}
$PAGE->reset_theme_and_output();
[, $course, $cm] = get_context_info_array($context->id);
require_login($course, false, $cm, false, true);
$PAGE->set_context($context);
}
/**
* Get context from passed parameters.
* The passed array must either contain a contextid or a combination of context level and instance id to fetch the context.
* For example, the context level can be "course" and instanceid can be courseid.
*
* See context_helper::get_all_levels() for a list of valid numeric context levels,
* legacy short names such as 'system', 'user', 'course' are not supported in new
* plugin capabilities.
*
* @param array $param
* @since Moodle 2.6
* @throws invalid_parameter_exception
* @return context
*/
protected static function get_context_from_params($param) {
if (!empty($param['contextid'])) {
return context::instance_by_id($param['contextid'], IGNORE_MISSING);
} else if (!empty($param['contextlevel']) && isset($param['instanceid'])) {
// Numbers and short names are supported since Moodle 4.2.
$classname = \core\context_helper::parse_external_level($param['contextlevel']);
if (!$classname) {
throw new invalid_parameter_exception('Invalid context level = '.$param['contextlevel']);
}
return $classname::instance($param['instanceid'], IGNORE_MISSING);
} else {
// No valid context info was found.
throw new invalid_parameter_exception(
'Missing parameters, please provide either context level with instance id or contextid'
);
}
}
/**
* Returns a prepared structure to use a context parameters.
* @return external_single_structure
*/
protected static function get_context_parameters() {
$id = new external_value(
PARAM_INT,
'Context ID. Either use this value, or level and instanceid.',
VALUE_DEFAULT,
0
);
$level = new external_value(
PARAM_ALPHANUM, // Since Moodle 4.2 numeric context level values are supported too.
'Context level. To be used with instanceid.',
VALUE_DEFAULT,
''
);
$instanceid = new external_value(
PARAM_INT,
'Context instance ID. To be used with level',
VALUE_DEFAULT,
0
);
return new external_single_structure([
'contextid' => $id,
'contextlevel' => $level,
'instanceid' => $instanceid,
]);
}
}