Hi,

I am quite new to Symfony (so this is a BEGINNER question) and are just trying to implement a VERY simple web application:

• When a user accesses the page (without and request parameter), a UUID is generated and the user should enter her name, email and shirt color.
• If she submits, data (uuid, name, email, shirt color) is stored in a database and the user gets an email with a link (leveraging the uuid) that she can use to come back later and change her mind/data (of the shirt color, or even her name or email).

That's all. Basically a CRUD without the "D", and yes, not super secure, but this is what we need.

I thought this would be super easy with Symfony, leveraging doctrine and forms. Any yes, there are many good examples out there that describe how to easily build such an application, simply creating an entity (more or less a POPO with some validation rules), a respective form and type and a controller and then let Symfony do the work. Even the official documentation shws this with a "Task" object. Cool, 10 min work (at most) which I think is great for such a simple use case. Validation of new data as well as then saving new users is super easy.

But the challenge I face: Whenever I want to change existing data, i.e. display the user's data and let her update it, she might do the mistake and delete some of the data, say her name. While in case of a new entry, the form validation would then show a user friendly error in that case (e.g., "Name should not be blank"), in case of an update, Symfony throws an exception, as a null value cannot be copied to what is expected to be a string.

// ...
#[Route('/edit/{id}', name: 'app_save')]
public function edit(Request $request, EntityManagerInterface $entityManager, User $user): Response
{
    $form = $this->createForm(UserType::class, $user);
    $form->handleRequest($request);      // <----- Exception thrown if one of the text fields is empty
    if ($form->isSubmitted() && $form->isValid()) {
// ...

I searched for that and found out that it is exactly what has been described here: #39106

It seems one should use DTOs and with that decouple the "business entity" (which should always be "valid") from form data (which may not). I really did a lot of searching, reading docs, even watching YT videos etc. - I simply cannot find a SIMPLE example on how this should work - the "update case" is never shown, only the "create" where you simply copy all form->data(). So I did it by myself, ending up with two more or less similar objects, one being the "entity" that is stored to/retrieved from the database with a couple of constraints (Non-Null, etc.) and one being the DTO with more or less the same data and the same constraints just used in the form (but despite the constraints technically allowing null properties!). And of course I wrote a lot of stupid code to copy data between the DTO and the business entity when preparing/processing the form.

Question: Did I make a fundamental mistake in creating all the stupid DTO / copy code? If yes, can someone please help me finding a minimal example that avoids that and does validation properly for "null"-values in the update case?

Comment: If I did NOT do a mistake and that is in general how it should work: I would say it is perfectly fine for more complex situations where the business entity really differs from the form data, e.g., because there is some more complex logic to derive the entity from the data etc. BUT: I strongly believe Symfony should provide an easy way for the simple "CRUD"-type of application - and as far as I can say, the "U" part is really annoying. Maybe one should have some sort of configuration value that makes the request handling in the form do it in a bit of a "relaxed" way (what obviously is the case when adding new data)?

Thanks for any help!

Jonas