铁矿石或CORS问题

我在Polymer 2.0上使用iron ajax时遇到问题。我的代码是基于Polymer 1.0的，我正在尝试调整它。我通过如下方式发送我的表格：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

模板：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

Iron Ajax设置：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

    <iron-localstorage name="user-storage" value="{{storedUser}}"></iron-localstorage>
    <app-data key="userData" data="{{storedUser}}"></app-data>

    <iron-ajax
        id="registerLoginAjax"
        method="post"
        content-type="application/json"
        handle-as="text"
        on-response="handleUserResponse"
        on-error="handleUserError"></iron-ajax>

错误似乎是一个CORS问题：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

无法加载XMLHttpRequest。 对飞行前请求的响应未通过访问控制检查： 响应中“Access Control Allow Origin”标头的值必须为 当请求的凭据模式为时，不能为通配符“*” “包括”。因此，不允许使用源“” 通道由发起的请求的凭据模式 XMLHttpRequest由withCredentials属性控制

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

---

我做错了什么？

更改

http://localhost:3001/sessions/create

backend发送响应头

Access Control Allow Origin:http://127.0.0.1:8081/

对来自

http://127.0.0.1:8081/

，而不是像现在这样发回响应头

访问控制允许原点：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

报告解释了原因：

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

当响应认证请求时，服务器必须在

访问控制允许原点

头的值中指定原点，而不是指定“

*

”通配符

        <div class="wrapper-btns">
            <paper-button raised class="primary" on-tap="postLogin">Log In</paper-button>
            <paper-button class="link" on-tap="postRegister">Sign Up</paper-button>
        </div>

---

服务器端有什么？聚合物1的使用是否正确？