Consider improving the file upload tutorial

[javiereguiluz]

A Symfony newcomer is having some troubles following it: symfony/symfony#19361

[wouterj]

So the problem here is that we use the same property for the file path saved in the DB and the file saved in the DB.

What's very clear here is that using entities in the form is not the good solution for file uploads. We should instead use a DTO for the form. This is a very good place to actually show this much better practice :)

[javiereguiluz]

I don't agree with Wouter's comment. Uploading a file in Symfony is already more complex than it should be. Forcing the user to create more classes and complicate things a bit more would be too much in my opinion.

My reasoning may sound simplistic, but this is what I think:

1. Symfony framework is a web framework
2. A framework helps you providing features to avoid repeating trivial and common tasks
3. Uploading files is a common and trivial task in web applications
4. Therefore, Symfony should provide "something" to make file uploads trivial

[xabbuh]

@javiereguiluz But these are two (not completely) different things: Even if we come up with a better technical solution in the Symfony core (which we would still need to find), we will still have to provide good docs for already released versions (where to me using a DTO is way better than putting stuff into your entities that doesn't belong there).

[Koc]

We could add link to bundles wich reduce boilerplate code and provide support of multiple storage systems and persistence layer, like https://github.com/dustin10/VichUploaderBundle or https://github.com/vitiko/IphpFileStoreBundle

[Koc]

relates to #5603

[javiereguiluz]

Closing this in favor of the file uploading meta-issue: #8255.