Handling image upload when one already exists

[seydu]

When I submit a form without uploading an image I lose the image I had previously uploaded.
I don't see anything in the doc to handle this situation.

Is something planed to handle this ?
I used to handle this with Javascript and some tweak server side:
The server sets some information in the response to let the JS know if an image already exists. If yes it hides the upload field, removes the "required" if any and adds a button to show the upload when clicked.

[dbu]

this seems a dilemma of http and the form layer: when submitting the form, the browser obviously does not re-send the file. the form layer does not magically insert the file when it was not changed - that could be very expensive and confusing as you don't know if the user uploaded a new file or you still have the same file. so you do need to detect this situation specifically - not sure why the form layer does not detect the file was not changed. if it would do that and not call the setter method, things would be simpler. this is what we use in the BlockBundle: https://github.com/symfony-cmf/BlockBundle/blob/master/Doctrine/Phpcr/ImagineBlock.php#L132-L176

do we have a document in the MediaBundle that would need the same logic?

[seydu]

Yes.
I have seen this problem in many applications (base on known framworks or in house ones).
Though the solution I described in my firt post is being used in many apps in an in house framework, I don't like it. And in the context of Symfony I don't want to allow myself to use it because there should be a cleaner way to do it.

I have a document that extends Symfony\Cmf\Bundle\MediaBundle\Doctrine\Phpcr\Image and adds an image (\Symfony\Cmf\Bundle\MediaBundle\Doctrine\Phpcr\Image).

Since I am SonataAdmin, I can use its functionality that allows to remove some fields before binding (I don't remember where I have seen it in the doc, I will have to check). Hoping a won't have a problem with the CRFS protection in the form layer.

[dbu]

i think we already have an issue talking about this: #8 - if you have a generic solution that you think we could provide with sonata / media bundle i would love to see PRs .

from a user point of view, i see two cases:

1. Image required: On new document, i must upload an image. Later on i may upload an image to replace the existing image.
2. Image optional: On a new or existing document i may upload an image to create/replace it. If there already is an image, i additionally have a little "delete" button to remove the currently uploaded image from the document on save.

I don't know what the most elegant and generic solution on server side is for this, how far the form layer can help with not overwriting an image when none was uploaded.