Speaking URLs - Slugs

A slug is a unique name for an resource. The index has an slug field for all indices and can be used to map a "speaking URL" segment to an index. Since an event can produce multiple indices, we need an extra logic to generate unique slugs for them.

Slug structure

The slug of an index consists out of multiple parts:

{1:base-slug}-{2?:slug-suffix}-{3?:regular-core-conflict-counter}

base-slug

Speaking part of the slug for each event using the SpeakingUrlInterface (or a fallback method).
slug-suffix (optional)

Additionally date suffix for events with multiple occurrences.
regular-core-conflict-counter (optional)

Counting suffix to prevent duplicates, if the previous slug already exists.

Custom base slug for own events

The SpeakingUrlInterface can be used to generate the base slug for events. Implement this interface in your event model and return a value e.g. a title or slug. Alternatively, you could name your slug field slug or path_segment.

Extend the slug generation

The slugs are generated inside SlugService and can be expanded by using the following PSR-14 events:

BaseSlugGenerationEvent
SlugSuffixGenerationEvent

SlugSuffixGenerationEvent example

This example shows how to add a custom suffix to the slug, in this case the start time of the event. A resulting slug could look like test-20201103-1715.

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\EventListener;

use HDNET\Calendarize\Event\SlugSuffixGenerationEvent;

final class AddEventTimeSlugListener
{
    public function __invoke(SlugSuffixGenerationEvent $event): void
    {
        // Optional: some additional checks, e.g. based on Model or page id (pid)
        // Get the start_time (seconds since day start) from the record
        $startTime = $event->getRecord()['start_time'];
        // Add to the existing slug (e.g. test-20201103) the current time (17:15)
        // resulting in test-20201103-1715
        $newSlug = $event->getSlug() . '-' . date('Hi', $startTime);
        // Update the slug
        $event->setSlug($newSlug);
    }
}

Then register the event in your extension's Configuration/Services.yaml:

services:
  # ...
  MyVendor\MyExtension\EventListener\AddEventTimeSlugListener:
    tags:
      - name: event.listener
        identifier: 'addEventTimeSlug'

See Events for more details on implementing PSR-14 events.