Conference URLs now use slugs instead of integer id

src/Controller/ConferenceController.php

@@ -21,7 +21,7 @@ class ConferenceController extends AbstractController
         ]);
     }
 
-    #[Route('/conference/{id}', name: 'conference')]
+    #[Route('/conference/{slug}', name: 'conference')]
     public function show(Request $request, Conference $conference, CommentRepository $commentRepository): Response
     {
         $offset = max(0, $request->query->getInt('offset', 0));

src/Entity/Conference.php

@@ -6,8 +6,11 @@ use App\Repository\ConferenceRepository;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
+use Doctrine\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
+use Symfony\Component\String\Slugger\SluggerInterface;
 
 #[ORM\Entity(repositoryClass: ConferenceRepository::class)]
+#[UniqueEntity('slug')]
 class Conference
 {
     #[ORM\Id]
@@ -30,6 +33,9 @@ class Conference
     #[ORM\OneToMany(targetEntity: Comment::class, mappedBy: 'conference', orphanRemoval: true)]
     private Collection $comments;
 
+    #[ORM\Column(length: 255, unique: true)]
+    private ?string $slug = null;
+
     public function __construct()
     {
         $this->comments = new ArrayCollection();
@@ -44,6 +50,13 @@ class Conference
         return $this->id;
     }
 
+    public function computeSlug(SluggerInterface $slugger)
+    {
+        if(!$this->slug || '-' === $this->slug) {
+            $this->slug = (string)$slugger->slug((string)$this)->lower();
+        }
+    }
+
     public function getCity(): ?string
     {
         return $this->city;
@@ -109,4 +122,16 @@ class Conference
 
         return $this;
     }
+
+    public function getSlug(): ?string
+    {
+        return $this->slug;
+    }
+
+    public function setSlug(string $slug): static
+    {
+        $this->slug = $slug;
+
+        return $this;
+    }
 }

src/EntityListener/ConferenceEntityListener.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\EntityListener;
+
+use App\Entity\Conference;
+use Doctrine\Bundle\DoctrineBundle\Attribute\AsEntityListener;
+use Doctrine\ORM\Events;
+use Doctrine\Persistence\Event\LifecycleEventArgs;
+use Symfony\Component\String\Slugger\SluggerInterface;
+
+#[AsEntityListener(event: Events::prePersist, entity: Conference::class)]
+#[AsEntityListener(event: Events::preUpdate, entity: Conference::class)]
+class ConferenceEntityListener
+{
+    public function __construct(
+        private SluggerInterface $slugger,
+    ) {
+    }
+
+    public function prePersist(Conference $conference, LifecycleEventArgs $event)
+    {
+        $conference->computeSlug($this->slugger);
+    }
+
+    public function preUpdate(Conference $conference, LifecycleEventArgs $event)
+    {
+        $conference->computeSlug($this->slugger);
+    }
+}