/**
 * Given a coursemodule object, this function returns the extra
 * information needed to print this activity in various places.
 * For this module we just need to support external urls as
 * activity icons
 *
 * @param stdClass $coursemodule
 * @return cached_cm_info info
 */
function lti_get_coursemodule_info($coursemodule)
{
    global $DB, $CFG;
    require_once $CFG->dirroot . '/mod/lti/locallib.php';
    if (!($lti = $DB->get_record('lti', array('id' => $coursemodule->instance), 'icon, secureicon, intro, introformat, name, typeid, toolurl, launchcontainer'))) {
        return null;
    }
    $info = new cached_cm_info();
    if ($coursemodule->showdescription) {
        // Convert intro to html. Do not filter cached version, filters run at display time.
        $info->content = format_module_intro('lti', $lti, $coursemodule->id, false);
    }
    if (!empty($lti->typeid)) {
        $toolconfig = lti_get_type_config($lti->typeid);
    } else {
        if ($tool = lti_get_tool_by_url_match($lti->toolurl)) {
            $toolconfig = lti_get_type_config($tool->id);
        } else {
            $toolconfig = array();
        }
    }
    // We want to use the right icon based on whether the
    // current page is being requested over http or https.
    if (lti_request_is_using_ssl() && (!empty($lti->secureicon) || isset($toolconfig['secureicon']) && !empty($toolconfig['secureicon']))) {
        if (!empty($lti->secureicon)) {
            $info->iconurl = new moodle_url($lti->secureicon);
        } else {
            $info->iconurl = new moodle_url($toolconfig['secureicon']);
        }
    } else {
        if (!empty($lti->icon)) {
            $info->iconurl = new moodle_url($lti->icon);
        } else {
            if (isset($toolconfig['icon']) && !empty($toolconfig['icon'])) {
                $info->iconurl = new moodle_url($toolconfig['icon']);
            }
        }
    }
    // Does the link open in a new window?
    $launchcontainer = lti_get_launch_container($lti, $toolconfig);
    if ($launchcontainer == LTI_LAUNCH_CONTAINER_WINDOW) {
        $launchurl = new moodle_url('/mod/lti/launch.php', array('id' => $coursemodule->id));
        $info->onclick = "window.open('" . $launchurl->out(false) . "', 'lti'); return false;";
    }
    $info->name = $lti->name;
    return $info;
}

/**
 * Prints a Basic LTI activity
 *
 * $param int $basicltiid       Basic LTI activity id
 */
function lti_view($instance) {
    global $PAGE, $CFG;

    if (empty($instance->typeid)) {
        $tool = lti_get_tool_by_url_match($instance->toolurl, $instance->course);
        if ($tool) {
            $typeid = $tool->id;
        } else {
            $typeid = null;
        }
    } else {
        $typeid = $instance->typeid;
    }

    if ($typeid) {
        $typeconfig = lti_get_type_config($typeid);
    } else {
        //There is no admin configuration for this tool. Use configuration in the lti instance record plus some defaults.
        $typeconfig = (array)$instance;

        $typeconfig['sendname'] = $instance->instructorchoicesendname;
        $typeconfig['sendemailaddr'] = $instance->instructorchoicesendemailaddr;
        $typeconfig['customparameters'] = $instance->instructorcustomparameters;
        $typeconfig['acceptgrades'] = $instance->instructorchoiceacceptgrades;
        $typeconfig['allowroster'] = $instance->instructorchoiceallowroster;
        $typeconfig['forcessl'] = '0';
    }

    //Default the organizationid if not specified
    if (empty($typeconfig['organizationid'])) {
        $urlparts = parse_url($CFG->wwwroot);

        $typeconfig['organizationid'] = $urlparts['host'];
    }

    if (!empty($instance->resourcekey)) {
        $key = $instance->resourcekey;
    } else if (!empty($typeconfig['resourcekey'])) {
        $key = $typeconfig['resourcekey'];
    } else {
        $key = '';
    }

    if (!empty($instance->password)) {
        $secret = $instance->password;
    } else if (!empty($typeconfig['password'])) {
        $secret = $typeconfig['password'];
    } else {
        $secret = '';
    }

    $endpoint = !empty($instance->toolurl) ? $instance->toolurl : $typeconfig['toolurl'];
    $endpoint = trim($endpoint);

    //If the current request is using SSL and a secure tool URL is specified, use it
    if (lti_request_is_using_ssl() && !empty($instance->securetoolurl)) {
        $endpoint = trim($instance->securetoolurl);
    }

    //If SSL is forced, use the secure tool url if specified. Otherwise, make sure https is on the normal launch URL.
    if ($typeconfig['forcessl'] == '1') {
        if (!empty($instance->securetoolurl)) {
            $endpoint = trim($instance->securetoolurl);
        }

        $endpoint = lti_ensure_url_is_https($endpoint);
    } else {
        if (!strstr($endpoint, '://')) {
            $endpoint = 'http://' . $endpoint;
        }
    }

    $orgid = $typeconfig['organizationid'];

    $course = $PAGE->course;
    $requestparams = lti_build_request($instance, $typeconfig, $course);

    $launchcontainer = lti_get_launch_container($instance, $typeconfig);
    $returnurlparams = array('course' => $course->id, 'launch_container' => $launchcontainer, 'instanceid' => $instance->id);

    if ( $orgid ) {
        $requestparams["tool_consumer_instance_guid"] = $orgid;
    }

    if (empty($key) || empty($secret)) {
        $returnurlparams['unsigned'] = '1';

        //Add the return URL. We send the launch container along to help us avoid frames-within-frames when the user returns
        $url = new moodle_url('/mod/lti/return.php', $returnurlparams);
        $returnurl = $url->out(false);

        if ($typeconfig['forcessl'] == '1') {
            $returnurl = lti_ensure_url_is_https($returnurl);
        }

//.........这里部分代码省略.........

    $lti = $DB->get_record('lti', array('id' => $cm->instance), '*', MUST_EXIST);
}
$course = $DB->get_record('course', array('id' => $cm->course), '*', MUST_EXIST);
$tool = lti_get_tool_by_url_match($lti->toolurl);
if ($tool) {
    $toolconfig = lti_get_type_config($tool->id);
} else {
    $toolconfig = array();
}
$PAGE->set_cm($cm, $course);
// set's up global $COURSE
$context = context_module::instance($cm->id);
$PAGE->set_context($context);
$url = new moodle_url('/mod/lti/view.php', array('id' => $cm->id));
$PAGE->set_url($url);
$launchcontainer = lti_get_launch_container($lti, $toolconfig);
if ($launchcontainer == LTI_LAUNCH_CONTAINER_EMBED_NO_BLOCKS) {
    $PAGE->set_pagelayout('frametop');
    //Most frametops don't include footer, and pre-post blocks
    $PAGE->blocks->show_only_fake_blocks();
    //Disable blocks for layouts which do include pre-post blocks
} else {
    if ($launchcontainer == LTI_LAUNCH_CONTAINER_REPLACE_MOODLE_WINDOW) {
        redirect('launch.php?id=' . $cm->id);
    } else {
        $PAGE->set_pagelayout('incourse');
    }
}
require_login($course);
// Mark viewed by user (if required).
$completion = new completion_info($course);

/**
 * Return the launch data required for opening the external tool.
 *
 * @param  stdClass $instance the external tool activity settings
 * @return array the endpoint URL and parameters (including the signature)
 * @since  Moodle 3.0
 */
function lti_get_launch_data($instance)
{
    global $PAGE, $CFG;
    if (empty($instance->typeid)) {
        $tool = lti_get_tool_by_url_match($instance->toolurl, $instance->course);
        if ($tool) {
            $typeid = $tool->id;
        } else {
            $typeid = null;
        }
    } else {
        $typeid = $instance->typeid;
        $tool = lti_get_type($typeid);
    }
    if ($typeid) {
        $typeconfig = lti_get_type_config($typeid);
    } else {
        // There is no admin configuration for this tool. Use configuration in the lti instance record plus some defaults.
        $typeconfig = (array) $instance;
        $typeconfig['sendname'] = $instance->instructorchoicesendname;
        $typeconfig['sendemailaddr'] = $instance->instructorchoicesendemailaddr;
        $typeconfig['customparameters'] = $instance->instructorcustomparameters;
        $typeconfig['acceptgrades'] = $instance->instructorchoiceacceptgrades;
        $typeconfig['allowroster'] = $instance->instructorchoiceallowroster;
        $typeconfig['forcessl'] = '0';
    }
    // Default the organizationid if not specified.
    if (empty($typeconfig['organizationid'])) {
        $urlparts = parse_url($CFG->wwwroot);
        $typeconfig['organizationid'] = $urlparts['host'];
    }
    if (isset($tool->toolproxyid)) {
        $toolproxy = lti_get_tool_proxy($tool->toolproxyid);
        $key = $toolproxy->guid;
        $secret = $toolproxy->secret;
    } else {
        $toolproxy = null;
        if (!empty($instance->resourcekey)) {
            $key = $instance->resourcekey;
        } else {
            if (!empty($typeconfig['resourcekey'])) {
                $key = $typeconfig['resourcekey'];
            } else {
                $key = '';
            }
        }
        if (!empty($instance->password)) {
            $secret = $instance->password;
        } else {
            if (!empty($typeconfig['password'])) {
                $secret = $typeconfig['password'];
            } else {
                $secret = '';
            }
        }
    }
    $endpoint = !empty($instance->toolurl) ? $instance->toolurl : $typeconfig['toolurl'];
    $endpoint = trim($endpoint);
    // If the current request is using SSL and a secure tool URL is specified, use it.
    if (lti_request_is_using_ssl() && !empty($instance->securetoolurl)) {
        $endpoint = trim($instance->securetoolurl);
    }
    // If SSL is forced, use the secure tool url if specified. Otherwise, make sure https is on the normal launch URL.
    if (isset($typeconfig['forcessl']) && $typeconfig['forcessl'] == '1') {
        if (!empty($instance->securetoolurl)) {
            $endpoint = trim($instance->securetoolurl);
        }
        $endpoint = lti_ensure_url_is_https($endpoint);
    } else {
        if (!strstr($endpoint, '://')) {
            $endpoint = 'http://' . $endpoint;
        }
    }
    $orgid = $typeconfig['organizationid'];
    $course = $PAGE->course;
    $islti2 = isset($tool->toolproxyid);
    $allparams = lti_build_request($instance, $typeconfig, $course, $typeid, $islti2);
    if ($islti2) {
        $requestparams = lti_build_request_lti2($tool, $allparams);
    } else {
        $requestparams = $allparams;
    }
    $requestparams = array_merge($requestparams, lti_build_standard_request($instance, $orgid, $islti2));
    $customstr = '';
    if (isset($typeconfig['customparameters'])) {
        $customstr = $typeconfig['customparameters'];
    }
    $requestparams = array_merge($requestparams, lti_build_custom_parameters($toolproxy, $tool, $instance, $allparams, $customstr, $instance->instructorcustomparameters, $islti2));
    $launchcontainer = lti_get_launch_container($instance, $typeconfig);
    $returnurlparams = array('course' => $course->id, 'launch_container' => $launchcontainer, 'instanceid' => $instance->id, 'sesskey' => sesskey());
    // Add the return URL. We send the launch container along to help us avoid frames-within-frames when the user returns.
    $url = new \moodle_url('/mod/lti/return.php', $returnurlparams);
    $returnurl = $url->out(false);
//.........这里部分代码省略.........