Background File Uploads using Filament Forms, FilePond, Livewire and Alpine.js: https://silvanhagen.com/writing/background-file-upload-in-filament-forms

LinkResource.php

<?php

namespace App\Filament\Resources;

use App\Filament\Resources\LinkResource\Pages;
use App\Models\Link;
use AshAllenDesign\FaviconFetcher\Facades\Favicon;
use Filament\Forms;
use Filament\Forms\Form;
use Filament\Forms\Set;
use Filament\Resources\Resource;
use Filament\Tables;
use Filament\Tables\Table;
use Illuminate\Http\UploadedFile;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Facades\URL;
use Illuminate\Support\Str;
use Livewire\Features\SupportFileUploads\TemporaryUploadedFile;

class LinkResource extends Resource
{
    protected static ?string $model = Link::class;

    protected static ?string $navigationIcon = 'heroicon-o-rectangle-stack';

    public static function form(Form $form): Form
    {
        return $form
            ->schema([
                Forms\Components\TextInput::make('url')
                    ->label('Website URL')
                    ->live(onBlur: true)
                    ->afterStateUpdated(function (Set $set, $state, $livewire) {
                        $title_from_url = Str::of($state)
                            ->remove(['http://', 'https://'])
                            ->before('/')
                            ->title();
                        $set('title', $title_from_url);

                        $favicon = Favicon::fetchAll($state)->largest();
                        $file = self::createTemporaryFileUploadFromUrl($favicon);

                        $livewire->dispatch('add-favicon', $file);
                    })
                    ->url()
                    ->required(),
                Forms\Components\TextInput::make('title')
                    ->required(),
                Forms\Components\FileUpload::make('favicon_path')
                    ->label('Favicon')
                    ->extraAlpineAttributes(['x-on:add-favicon.window' => '
                        const pond = FilePond.find($el.querySelector(".filepond--root"));
                        setTimeout(() => {
                            pond.removeFiles({ revert: true });
                            pond.addFile($event.detail);
                        }, 750);',
                    ])
                    ->image(),
            ])->columns(1);
    }

    public static function createTemporaryFileUploadFromUrl($favicon): string
    {
        // Step 1: Save the file to a temporary location
        $tempFilePath = tempnam(sys_get_temp_dir(), 'upload');
        file_put_contents($tempFilePath, $favicon->content());

        // Step 2: Create a UploadedFile instance
        $mimeType = mime_content_type($tempFilePath);
        $tempFile = new UploadedFile($tempFilePath, basename($favicon->getFaviconUrl()), $mimeType);
        $path = Storage::put('livewire-tmp', $tempFile);

        // Step 3: Create a TemporaryUploadedFile instance
        $file = TemporaryUploadedFile::createFromLivewire($path);

        return URL::temporarySignedRoute(
            'livewire.preview-file', now()->addMinutes(30)->endOfHour(), ['filename' => $file->getFilename()]
        );
    }
}