Laravel 5 - Validation - validation

Question

I am confuse how can I validate a user's username if I am updating it. Here's the scenario, if I click a specific user in list of users page it will redirect into a page which has a form with user's data in the form. Now, I have:
public function updateUser(Request $request){
$this->validate($request, [
'username' => 'required|unique:users',
'name' => 'required|max:255'
]);
}
UPDATE
$this->validate($request, [
'name' => 'unique:roles,name,'.$request->id
]);
I know the part where 'username' => 'required|unique:users' is checking if the username exists in the users table, but what if I dont want to change/update the username, and I just want to update the other field, then it says that the username is already exists. How can I validate it in a right way.
Need help guys. This can also help others for this kind of problem.

Answer 1

Laravel will accept a new parameter for the key of the table. This should be the id of the element you would like to ignore in your query.
something like 'username' => 'required|unique:users,username,'.$request->get('id'),
You will have to pass the id variable in your request when updating.
Laravel documentation: https://laravel.com/docs/5.4/validation#rule-unique
You can also try using the Rule class (search for "Forcing A Unique Rule To Ignore A Given ID"), which was added in Laravel version 5.3.
You can see an example of usage of my answer in the documentation at:
https://laravel.com/docs/5.2/validation#rule-unique (search for "Forcing A Unique Rule To Ignore A Given ID")
Update as per question update:
$this->validate($request, [
'name' => 'required|unique:roles, name,'.$request->id
]);

Answer 2

you want to update profile and at that time you stuck with this error "username is already exists". so my suggestion is just remove the required validation from username if username is not updated then don't send it to server, so you no need to check whether it's exists or not in table and also if want to check particular column you can write like this
public function updateUser(Request $request){
$this->validate($request, [
'username' => 'unique:users,column-name',
'name' => 'required|max:255'
]);
}
in above case if we receive a username then we check it's uniqueness else not

Answer 3

You just need to check if the user exists or not
'username' => 'exists:users'
If the user exists in the database you will update it.
What wrong you are doing is: You are trying to update a user and validating that the username should be unique (this validation should be applied during user creation), that is not correct.
Thanks.
EDIT 1
Generally, username or email is a key column which you should not allow the user to update. Otherwise, this problem will always exist.
EDIT 2
I agree with the actual scenario that we can not assume that the username field will always remain same and the user can not update it. If the user is updating the username then you can try this code.
'username' => 'required|unique:users,username,'.$user->id
If your table uses a primary key column name other than id, you may specify it as the fourth parameter:
'username' => 'required|unique:users,username,'.$user->id.',user_id'