Customizing Prezet Front Matter

Prezet makes it easy to customize the front matter of your markdown files. To learn more about how front matter works in general, check out the Typed Front Matter documentation.

This guide walks you through extending Prezet's default FrontmatterData class so that Prezet recognizes your custom front matter fields.

#The Default FrontmatterData Class

Prezet includes a default FrontmatterData class that validates essential fields like title, excerpt, category, draft, and more. You can review the source code here: FrontmatterData.php.

Key properties include:

• title (string)
• excerpt (string)
• category (nullable string)
• image (nullable string)
• draft (boolean)
• date (Carbon instance)
• author (nullable string)
• slug (nullable string)
• key (nullable string)
• tags (array)

Prezet uses the laravel-validated-dto package to ensure the fields in your YAML front matter are strictly typed.

#Adding Custom Fields

#1. Create a Custom Class

In app/Data/CustomFrontmatterData.php, you might add a legacy field to identify older docs you'd like to handle differently:

<?php

namespace App\Data;

use BenBjurstrom\Prezet\Data\FrontmatterData;
use WendellAdriel\ValidatedDTO\Attributes\Rules;

class CustomFrontmatterData extends FrontmatterData
{
    // Mark docs as "legacy: true" in the front matter if they should be excluded from certain features
    #[Rules(['nullable', 'bool'])]
    public ?bool $legacy;
}

Then your markdown front matter might look like:

---
title: "My Old Docs"
date: 2023-01-01
legacy: true
draft: false
---

#2. Override the Default in the Service Container

In a service provider (e.g., AppServiceProvider), bind Prezet's default FrontmatterData to your custom class:

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use BenBjurstrom\Prezet\Data\FrontmatterData;
use App\Data\CustomFrontmatterData;

class AppServiceProvider extends ServiceProvider
{
    public function register(): void
    {
        // Swap out the default front matter data for your custom class
        $this->app->bind(FrontmatterData::class, CustomFrontmatterData::class);
    }

    public function boot(): void
    {
        //
    }
}

This ensures that any time Prezet processes front matter, it uses your CustomFrontmatterData.