API Rails上的获取请求不返回json

Question

在Rails API中,我在UsersController中有一个登录POST方法,它接受2个参数(邮件和密码),如果找到记录则检入DB,如果是,则返回JSON.

  def login(mail, password)
    mail, password = params.values_at(:mail, :password)
    user = User.where(mail: mail, password: password)
    render json: user
  end

在我的正面,在React中,我使用fetch调用此方法,该方法在表单中获取邮件和密码值,并期望在我的用户中将用户设置为JSON 'res':

  login = () => {
    if(this.state.mail != null && this.state.password != null){
        fetch('http://127.0.0.1:3001/api/login', {
            method: 'post',
            body: JSON.stringify({
                            mail: this.state.mail,
                            password: this.state.password
                        }),
            headers: {
                'Accept': 'application/json',
                'Content-type': 'application/json'
            }
        })
        .then((res) => {
            console.log(res)
            if(res.data.length === 1 ){
                const cookies = new Cookies();
                cookies.set('mercato-cookie',res.data[0].id,{path: '/'});
                this.setState({redirect: true})
            }
        })
    }    bodyUsed: false
headers: Headers {  }
ok: true
redirected: false
status: 200
statusText: "OK"
type: "cors"
url: "http://127.0.0.1:3001/api/login"
__proto__: ResponsePrototype { clone: clone(), arrayBuffer: arrayBuffer(), blob: blob(), … } auth.js:32

  }

问题是我res不符合我的回报render json: user,所以我做了一个console.log(res):

Response
bodyUsed: false
headers: Headers {  }
ok: true
redirected: false
status: 200
statusText: "OK"
type: "cors"
url: "http://127.0.0.1:3001/api/login"
__proto__: ResponsePrototype { clone: clone(), arrayBuffer: arrayBuffer(), blob: blob(), … } auth.js:32

我尝试返回简单的JSON文本,以防我的user变量出现问题,并尝试更改render json: user为format.json { render json: user }但没有结果:/

我在Postman上发出了请求,它返回了合适的JSON,所以我猜问题来自于我fetch？

Answer 1

Fetch的响应不会自动转换为JSON,您需要调用response.json()(返回一个promise)以获取JSON值.从MDN看这个例子,或者这里有一些ES6来匹配你的代码:

fetch(myRequest)
  .then(response => response.json())
  .then((data) => {
    // I'm assuming you'll have direct access to data instead of res.data here,
    // depending on how your API is structured
    if (data.length === 1) {
      const cookies = new Cookies();
      cookies.set('mercato-cookie', data[0].id, {path: '/'});
      this.setState({redirect: true});
    }
  });