Custom Upload of Avatar in Nova

HashSha256UploadedFileMacro.php

<?php

// put this in AppServiceProvider::register to make the hash of the filename
// correspond to the SHA256 of the *CONTENTS* of the UploadedFile automatically
UploadedFile::macro('setHash', function () {
    /** @var UploadedFile $this */
    $this->hashName = hash_file('sha256',
        $this->getRealPath(), false);
});

ImageFieldCustomNova.php

<?php

// this is put in the fields of a resource
Image::make('Avatar', 'avatar_url')
    ->disk('azure')
    ->store(function (Request $request, UserModel $model) {
        $corp = $model->corp;
        $path = '/' . $corp->subdomain;
        /** @var UploadedFile $attachment */
        $attachment = $request->avatar_url;

        $attachment->setHash();

        $url = $attachment->store($path, 'azure');

        return [
            'avatar_url' => $url,
            'avatar_size' => $attachment->getSize(),
            'avatar_filename' => $attachment->getClientOriginalName(),
        ];
    })
    ->download(function($req, $model, $disk, $value) {
        return Storage::disk($disk)->download($value, $model->avatar_filename);
    })
    // I had to put this on the Field declaration to avoid the previous uploaded file be deleted
    ->prunable(false)
    ->deletable(false),