Laravel Auth::attempt() 返回 false

In case you want to preserve this structure, you need to flash the request data of postRegister() into the session (which is persistent between requests) and then retrieve it in the postLogin() method using Session facade, session() helper or the actual IlluminateSessionSessionManager class.

我的意思是:
(我稍微修改了您的代码；删除了额外的变量，使其更简洁，等等.)

public function postRegister(Request $request)
{
    // Retrieve all request data including username, email & password.
    // I assume that the data IS validated.
    $input = $request->all();

    // Hash the password
    $input['password'] = bcrypt($input['password']);

    // Create the user
    User::create($input);

    // Redirect
    return redirect()
        // To the route named `login`
        ->route('login')

        // And flash the request data into the session,
        // if you flash the `$input` into the session, you'll
        // get a "Failure" message again. That's because the 
        // password in the $input array is already hashed and 
        // the attempt() method requires user's password, not 
        // the hashed copy of it. 
        //
        ->with($request->only('username', 'password'));
}

public function postLogin(Request $request)
{
    // Create the array using the values from the session
    $credentials = [
        'username' => session('username'),
        'password' => session('password'),
    ];

    // Attempt to login the user
    if (Auth::attempt($credentials)) {
        return redirect()->route('dashboard');
    }

    return 'Failure';
}

我强烈建议您不要使用这种方法.这样，应该负责登录用户的 postLogin() 方法的实现与会话数据耦合在一起，这是不好的.这样，您就无法独立于 postRegister 使用 postLogin.

public function postRegister(Request $request)
{
    $input = $request->all();

    $input['password'] = bcrypt($input['password']);

    User::create($input);

    // event(UserWasCreated::class);

    if (Auth::attempt($request->only('username', 'password'))) {
        return redirect()
            ->route('dashboard')
            ->with('Welcome! Your account has been successfully created!');
    }

    // Redirect
    return redirect()
        // To the previous page (probably the one generated by a `getRegister` method)
        ->back()
        // And with the input data (so that the form will get populated again)
        ->withInput();
}