Laravel old() 输入值在表单验证后总是返回 Null

Question

I have a basic form (available for auth users)

<form method="POST" action="/admin/insert">
@csrf  
<div class="form-group">
<label>{{ __($cv->name) }}</label>
<input type="text" name="name" class="form-control @error($ck) is-invalid @enderror"  value="{{ old('name') }}" >
</div>
<button type="submit" class="btn btn-primary me-2">{{ __('Submit') }}</button>
</form>

For testing purposes, I intentionally failed validation for form in controller.

if ($validator->fails()) {
    return back()->withErrors($validator)
        ->withInput($request->input());
}

My session friver is file:

driver' => env('SESSION_DRIVER', 'file'),

Problem is that old('name') always returns NULL in blade, and It doesn't fills form value if validation failed.

Where is the problem? (Note: Login form work perfectly)

Answer 1

The problem may be caused by the fact that you're using the file session driver. The file session driver stores session data in the file system, and when a user navigates away from a page or closes their browser, their session data is lost. In this case, the old input function in your blade template is not able to retrieve the previously entered data from the session because the session data has been lost.

To solve this, you can change your session driver to cookie, database or memcached/redis in your.env file. These drivers will store session data on the user's browser as a cookie or in a database, allowing the old input function to retrieve the previously entered data even after the user navigates away from the page or closes their browser.

You should also make sure that your form includes the old input function where appropriate, that way the form will repopulate with the previously entered data if validation fails.

Another cause of the problem might be related to a CSRF token problem. Since your form includes the @csrf directive, you will need to make sure that the CSRF_TOKEN variable is being set in the config/session.php file, or in case you have the variable defined in your.env file that the value is correct.

Finally, make sure you are using the POST method for form submission, since the old input function only retrieves data from the previous POST request, so in case you are doing a GET request the function will not retrieve the data from the previous request.