Form::file: How to repopulate with Input::old After Validation Errors and/or on Update?

问题

In my PhotosController, I am trying to modify the edit action so that it shows the existing value in the Form::file() input field (and, so that it repopulates the field if validation fails).

if ($validation->passes())
{
        // saves the image on the FS and updates the db entry
}

    return Redirect::route('photos.edit')
        ->withInput(Input::all())
        ->withErrors($validation)
        ->with('message', 'There were validation errors.');

The uploading process works fine, but when I view an existing record, or if validation fails upon creation, the Form::file doesn't show the value. I looked up the method in the api, and it only accepts the name and optional options arrays. Whereas, the other methods in the FormBuilder class allow us to set the value using Input::old().

I've tried passing in the following values to withInput, but they've been to no avail: * Input::all() * Input::old() * Input::except('photo_path') * Input::get('photo_path')

How can I update this so that if validation fails, or if a user views an existing record, the Form::file() method will show the existing value?

I'm sure that I'm overlooking something incredibly simple because I haven't found other threads of people asking this...

回答1:

Apparently you can't. Browsers don't allow you to set a value on a file input for security reasons.

There are two silimar questions, not laravel related but i think answers could help you:

Can you re-populate file inputs after failed form submission with PHP or JavaScript?

Restoring the value of a input type=file after failed validation

回答2:

Maybe your best shot would be to make the validation client-side (javascript/jquery).

Of course there has to be (ALWAYS) server-side validation. (remember javascript can be disabled on client-side).

But I believe that, this way 99.99% of the cases, the form submission will be successful!

Basically, when is indeed submit, it is already validated with sames rules as the servers, so it will not submit until it is not "as the server likes" :)

Cheers

回答3:

For complex form submits I would recommend to use AJAX:

1. You may do a first AJAX form send that does the server side validation.
2. Then, if it's all fine you should launch via Javascript the form POST with file input.

I've answered a similar question for Laravel there but I hope it will be helpful for a general approach: Laravel 5.1: keep uploaded file as old input

回答4:

Remove the redirect, your validation and input values should show on the same page, only redirect upon success.

来源：https://stackoverflow.com/questions/22659345/formfile-how-to-repopulate-with-inputold-after-validation-errors-and-or-on