10. 소셜 로그인 구현

@Injectable()
export class GoogleStrategy extends PassportStrategy(Strategy, 'google') {
  constructor() {
    super({
      clientID: process.env.OAUTH_GOOGLE_CLIENT_ID,
      clientSecret: process.env.OAUTH_GOOGLE_CLIENT_SECRET,
      callbackURL: process.env.BASE_URL + '/auth/google/callback',
      scope: ['email', 'profile'],
    });
  }

  // refreshToken이 필요한 경우 설정
  authorizationParams(): { [key: string]: string } {
    return {
      access_type: 'offline',
      prompt: 'select_account',
    };
  }

  async validate(
    accessToken: string,
    refreshToken: string,
    profile: Profile,
    done: VerifyCallback,
  ): Promise<void> {
    const { name, emails, provider } = profile;

    const socialLoginUserInfo = {
      email: emails[0].value,
      firstName: name.givenName,
      lastName: name.familyName,
      socialProvider: provider,
      accessToken,
      refreshToken,
    };

    done(null, socialLoginUserInfo);
  }
}

@Injectable()
export class KakaoStrategy extends PassportStrategy(Strategy, 'kakao') {
  constructor() {
    super({
      clientID: process.env.OAUTH_KAKAO_CLIENT_ID,
      callbackURL: process.env.BASE_URL + '/auth/kakao/callback',
    });
  }

  async validate(
    accessToken: string,
    refreshToken: string,
    profile: Profile,
    done: VerifyCallback,
  ): Promise<void> {
    const { id, username, _json } = profile;

    const socialLoginUserInfo = {
      id,
      username,
      email: _json.kakao_account.email,
      accessToken,
      refreshToken,
    };

    done(null, socialLoginUserInfo);
  }
}

import { AuthGuard as Auth } from '@nestjs/passport';

@UseGuards(Auth('google'))
@Get('google')
googleAuth() {
  return 'Google OAuth';
}

@UseGuards(Auth('google'))
@Post('google/callback')
async loginGoogle(@Req() req, @Res() res: Response) {
  const user = await this.authService.getUserByEmail(req.user.email);

  const input = {
    email: req.user.email,
    password: 'OAuth',
    nickname: req.user.firstName,
  };

  const { accessToken, refreshToken } = user
    ? await this.authService.signIn(input)
    : await this.authService.signup(input);

  res
    .cookie('accessToken', accessToken, this.cookieOptions)
    .cookie('refreshToken', refreshToken, this.cookieOptions)
    .send({ message: 'google 로그인 성공' });
}

<Link href={`${process.env.NEXT_PUBLIC_BASE_URL}/api/auth/google`}>
  구글 로그인
</Link>

export default function Callback() {
  const { asPath, query, push, isReady } = useRouter();
  const { openId } = query;
  const [errorMessage, setErrorMessage] = useState('');

  useEffect(() => {
    if (!isReady) return;

    fetcher<Response>({
      url: process.env.NEXT_PUBLIC_BASE_URL + asPath,
      method: 'post',
    }).then((res) => {
      if (res.message === `${openId} 로그인 성공`) push('/');
      else setErrorMessage(res.message);
    });
  }, [asPath, openId, push, isReady]);

  return <>{errorMessage}</>;
}