Add support to change request contents

[infostreams]

This pull request add support to change which requests are issued. It does this by allowing you to inject a different implementation of the (new) ICalDAVRequestFactory into the CalDAVRequestFactory, thereby adding support to change what goes into a specific request.

It also adds support to retrieve the full list of found properties of a request.

My use case is that I added a custom property to my calendars, and I want to request that property. However, I either do not understand the Facades or I might have missed how I can change the outgoing requests. Every class is final (which is a good thing), but there are no ways do to dependency injection either.

With this implementation I can now do the following:

    CalDAVRequestFactory::setInstance(new Calendar\CalDAVRequestFactory());

    $this->client = new CalDavClient(....)

and then in Calendar\CalDAVRequestFactory:

namespace App\Helpers\Calendar;

use CalDAVClient\Facade\Requests\IAbstractWebDAVRequest,
    CalDAVClient\Facade\Requests\ICalDAVRequestFactory,
    CalDAVClient\Facade\Requests\UserPrincipalRequest,
    CalDAVClient\Facade\Requests\CalendarHomeRequest,
    CalDAVClient\Facade\Requests\GetCalendarRequest,
    CalDAVClient\Facade\Requests\CalendarSyncRequest,
    CalDAVClient\Facade\Requests\CalendarMultiGetRequest,
    CalDAVClient\Facade\Requests\CalendarQueryRequest,
    CalDAVClient\Facade\Requests\CalendarCreateRequest,
    CalDAVClient\Facade\Requests\EventCreateRequest,
    CalDAVClient\Facade\Requests\EventUpdateRequest,

    // redefine the GetCalendarsRequest
    App\Helpers\Calendar\Requests\GetCalendarsRequest;


class CalDAVRequestFactory implements ICalDAVRequestFactory {

    /**
     * Builds a request of a certain type.
     *
     * @param string $type
     * @param array $params
     * @return IAbstractWebDAVRequest|null
     * @throws \InvalidArgumentException
     */
    public function build($type, $params = [])
    {
          // omitted for brevity, basically literally copy-pasted from the default CalDAVRequestFactory
    }
}

This would then allow me to define my custom request in App\Helpers\Calendar\Requests\GetCalendarsRequest, and I can access my custom property as follows:

/**
 * @var $calendars \CalDAVClient\Facade\Responses\GetCalendarsResponse
 */
$calendars = $this->client->getCalendars($calendar_home_url);

/**
 * @var $responses[] \CalDAVClient\Facade\Responses\GetCalendarMultiResponse
 */
$responses = $calendars->getResponses();

/**
 * @var $multiresponse \CalDAVClient\Facade\Responses\GetCalendarMultiResponse
 */
foreach ($responses as $multiresponse) {

    /**
     * @var $multi[] \CalDAVClient\Facade\Responses\GetCalendarResponse
     */
    $multi = $multiresponse->getResponses();

    /**
     * @var $r \CalDAVClient\Facade\Responses\GetCalendarResponse
     */
    foreach ($multi as $r) {
        $props = $r->getFoundProps();

        if (!empty($r->getDisplayName())) {

            $list[] = [
                'title' => $r->getDisplayName(),
                'link' => $r->getHRef(),
                'color' => $r->getColor(),
                'ctag' => $r->getCTag(),
                'MY_CUSTOM_PROPERTY => $props['MY_CUSTOM_PROPERTY'] 
            ];
        }
    }
}

I've toyed with the idea of having a DefaultCalDAVRequestFactory or an AbstractCalDAVRequestFactory so that I did not have to copy-paste the 'build' method and could just do parent::build()or $this->buildDefault() or something, but they were all messy and I didn't find a clean / satisfactory solution.