Laravel update model with unique validation rule for attribute

Working within my question:

public function update($id, $data) {
    $user = $this->findById($id);
    $user->fill($data);
    $this->validate($user->toArray(), $id);
    $user->save();
    return $user;
}


public function validate($data, $id=null) {
    $rules = User::$rules;
    if ($id !== null) {
        $rules['username'] .= ",$id";
        $rules['email'] .= ",$id";
    }
    $validation = Validator::make($data, $rules);
    if ($validation->fails()) {
        throw new ValidationException($validation);
    }
    return true;
}

is what I did, based on the accepted answer above.

EDIT: With Form Requests, everything is made simpler:

<?php namespace App\Http\Requests;

class UpdateUserRequest extends Request
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            'name' => 'required|unique:users,username,'.$this->id,
            'email' => 'required|unique:users,email,'.$this->id,
        ];
    }
}

You just need to pass the UpdateUserRequest to your update method, and be sure to POST the model id.

Append the id of the instance currently being updated to the validator.

1. Pass the id of your instance to ignore the unique validator.

2. In the validator, use a parameter to detect if you are updating or creating the resource.

If updating, force the unique rule to ignore a given id:

//rules
'email' => 'unique:users,email_address,' . $userId,

If creating, proceed as usual:

//rules
'email' => 'unique:users,email_address',

Unique Validation With Different Column ID In Laravel

'UserEmail'=>"required|email|unique:users,UserEmail,$userID,UserID"

Another elegant way...

In your model, create a static function:

public static function rules ($id=0, $merge=[]) {
    return array_merge(
        [
            'username'  => 'required|min:3|max:12|unique:users,username' . ($id ? ",$id" : ''),
            'email'     => 'required|email|unique:member'. ($id ? ",id,$id" : ''),
            'firstname' => 'required|min:2',
            'lastname'  => 'required|min:2',
            ...
        ], 
        $merge);
}

Validation on create:

$validator = Validator::make($input, User::rules());

Validation on update:

$validator = Validator::make($input, User::rules($id));

Validation on update, with some additional rules:

$extend_rules = [
    'password'       => 'required|min:6|same:password_again',
    'password_again' => 'required'
];
$validator = Validator::make($input, User::rules($id, $extend_rules));

Nice.