1.前後端不分離 （form表單提交）

控制器定義驗證規則

<?php

namespace App\Http\Controllers\Admin;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Validator;

class LoginController
{
    /**
     * @param Request $request
     * 登入
     */
    public function login(Request $request)
    {
        $post['name'] = $request
 
->input('name');
        $post['password'] = $request->input('password');

        $messages = [
            'name.required' => '請輸入賬號',
            'name.max' => '賬號錯誤',
            'password.required' => '請輸入密碼',
            'password.max' => '密碼錯誤',
            ];

        Validator
 
::make($post, [
            'name' => 'required|max:20',
            'password' => 'required|max:30',
        ],$messages)->validate();

    }
}

前端

@error('name')
   <span class="invalid-feedback" role="alert">
       <strong>{{ $message }}</strong>
   </span>
@enderror
 

2.前後端分離

<?php

namespace App\Http\Controllers\Admin;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Validator;

class LoginController
{
    /**
     * @param Request $request
     * 登入
     */
    public function login(Request $request)
    {
        $post['name'] = $request->input('name');
        $post['password'] = $request->input('password');

        $messages = [
            'name.required' => '請輸入賬號',
            'name.max' => '賬號錯誤',
            'password.required' => '請輸入密碼',
            'password.max' => '密碼錯誤',
            ];

        $validator = Validator::make($post, [
            'name' => 'required|max:20',
            'password' => 'required|max:30',
        ],$messages);
        
        if ($validator->fails()){
            //返回錯誤資訊
            //{
            //    "name": [
            //        "賬號錯誤"
            //    ],
            //    "password": [
            //        "密碼錯誤"
            //    ]
            //}
            return $validator->errors();
        }

    }
}