Caliper: An example of using caliper-php to send an event with custom action and context.

caliper_custom_action_example.php

<?php
require_once 'vendor/autoload.php';

use IMSGlobal\Caliper\actions\Action;
use IMSGlobal\Caliper\Client;
use IMSGlobal\Caliper\context\Context;
use IMSGlobal\Caliper\entities\agent\Person;
use IMSGlobal\Caliper\entities\agent\SoftwareApplication;
use IMSGlobal\Caliper\entities\media\MediaLocation;
use IMSGlobal\Caliper\entities\media\VideoObject;
use IMSGlobal\Caliper\events\MediaEvent;
use IMSGlobal\Caliper\Options;
use IMSGlobal\Caliper\request\HttpRequestor;
use IMSGlobal\Caliper\Sensor;
use IMSGlobal\Caliper\util;

class CustomAction extends Action {
    const
        STREAMED_TO_TIME = 'StreamedToTime';
}

// In order for UDP to accept a custom action, a custom context must be used.
// NOTE: If an array of context URIs is used, the serialization code in
// caliper-php gives warnings, like…
// `PHP Warning:  Array to string conversion in /umich-caliper-php/src/util/BasicEnum.php on line 104`
// These are harmless, but annoying.  This will be addressed in a future
// release of caliper-php.
// As a workaround to avoid warnings, use a single URI instead of
// multiple.  A single, non-standard URI is good enough to indicate to UDP
// that this event is special and UDP will accept the custom action.
// Technically, the multiple context should be used here.
class CustomContext extends Context {
    const
        SINGLE = 'http://example.edu/caliper/context/v1p1_custom.json',
        MULTIPLE = [
            parent::CONTEXT,
            self::SINGLE],
        __default = self::SINGLE;
}

date_default_timezone_set(
    DateTimeZone::listIdentifiers(DateTimeZone::UTC)[0]);

$sensorId = 'umich_caliper_example';

$options = (new Options())
    ->setApiKey('super_secret_key')
    ->setDebug(true)
    ->setHost('https://lti.tools/caliper/event?key=' . $sensorId);

$sensor = (new Sensor($sensorId))
    ->registerClient('http',
        new Client('clientId',
            $options));

$video = (new VideoObject('https://example.edu/videos/' .
    util\UuidUtil::makeUuidV4()))
    ->setDuration('PT59M59S')
    ->setName('A Highly Important Instructional Video')
    ->setDateCreated(new DateTime('2016-05-19'));

// Current minute and seconds as pseudorandom video time
$currentVideoTime = date('\P\Ti\Ms\S');

$event = (new MediaEvent())
    // Using a subclass of Context seems like a complicated way to set context.
    // Ideally, the context of events should be based on the context(s)
    // of their entities.
    ->setContext(new CustomContext())

    // Example of using multiple contexts.
    // ->setContext(new CustomContext(CustomContext::MULTIPLE))

    // Ideally, caliper-php should also set context on actions, but it
    // doesn't.  If it did, the event context could be based on the action
    // context, as described above.
    ->setAction(new CustomAction(CustomAction::STREAMED_TO_TIME))
    
    ->setActor(new Person('https://example.edu/user/' .
        get_current_user()))
    ->setEventTime(util\TimestampUtil::makeDateTimeWithSecondsFraction())
    ->setObject($video)
    
    // The intent of the `StreamedToTime` custom action is to mark when
    // the media playback reaches a quartile.  There aren't any Caliper
    // media entities which encode the percentage of playback (yet),
    // so it can be encoded in an `extensions` property of an appropriate
    // entity for now.
    ->setTarget(
        (new MediaLocation($video->getId() . '#currentTime=' . $currentVideoTime))
            ->setIsPartOf($video->makeReference())
            ->setCurrentTime($currentVideoTime)
            ->setExtensions([
                'percentage' => 0.25,
            ])
    )
    
    ->setEdApp((new SoftwareApplication('https://example.edu/video_player'))
        ->setVersion('1.2')
        ->setDateCreated(new DateTime('2015-02-09T12:25'))
    );

/*
 * NOTE: The next few blocks of code are for debugging and demonstration
 * purposes.  It is not necessary for sending events.
 */

// Makes JSON for event, but includes attributes without values
// print json_encode($event->jsonSerialize(),
//         $options->getJsonEncodeOptions()) . PHP_EOL;

// Requestor-based serialization removes attributes without values and
// includes an envelope.
$requestor = new HttpRequestor($options);
$envelope = $requestor->createEnvelope($sensor, $event);

// Using `@` here suppresses warnings about context array instead of string.
// However, all other warnings are also suppressed, so be careful.
// It may be better to use a single string context instead of an array.
$payload = $requestor->serializeData($envelope);
print $payload . PHP_EOL;

/*
 * End of debugging and demonstration code.
 */

// As above, `@` suppresses warnings about multiple contexts.  Caveat emptor.
try {
    @$sensor->send($sensor, $event);
} catch (\RuntimeException $sendException) {
    echo 'Error sending event: ' . $sendException->getMessage() . PHP_EOL;
}