提取给出一个空的响应主体 [英] fetch gives an empty response body

问题描述

我有一个react/redux应用程序，我正在尝试向服务器发送一个简单的GET请求:

I have a react/redux application and I'm trying to do a simple GET request to a sever:

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
}).then((response) => {
  console.log(response.body); // null
  return dispatch({
    type: "GET_CALL",
    response: response
  });
})
.catch(error => { console.log('request failed', error); });

问题在于.then()函数中的响应主体为空，我不确定为什么.我在网上检查了示例，看起来我的代码应该可以正常工作，因此我显然在这里遗漏了一些东西. 关键是，如果我在Chrome的开发工具中选中了网络"标签，则发出请求并收到了我要查找的数据.

The problem is that the response body is empty in the .then() function and I'm not sure why. I checked examples online and it looks like my code should work so I'm obviously missing something here. The thing is, if I check the network tab in Chrome's dev tools, the request is made and I receive the data I'm looking for.

有人可以照亮它吗?

我尝试转换响应.

使用.text():

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
})
.then(response => response.text())
.then((response) => {
  console.log(response); // returns empty string
  return dispatch({
    type: "GET_CALL",
    response: response
  });
})
.catch(error => { console.log('request failed', error); });

和.json():

fetch('http://example.com/api/node', {
  mode: "no-cors",
  method: "GET",
  headers: {
    "Accept": "application/json"
  }
})
.then(response => response.json())
.then((response) => {
  console.log(response.body);
  return dispatch({
    type: "GET_CALL",
    response: response.body
  });
})
.catch(error => { console.log('request failed', error); }); // Syntax error: unexpected end of input

查看chrome开发工具:

Looking in the chrome dev tools:

推荐答案

我刚刚遇到了这个问题.如答案所述，使用mode: "no-cors"将为您提供一个opaque response，它似乎没有返回数据在体内.

I just ran into this. As mentioned in this answer, using mode: "no-cors" will give you an opaque response, which doesn't seem to return data in the body.

opaque:跨源资源的"no-cors"请求的响应. 受到严格限制.

opaque: Response for "no-cors" request to cross-origin resource. Severely restricted.

就我而言，我正在使用Express.安装Express的 cors 并对其进行配置并删除mode: "no-cors"后，我得到了一个承诺.响应数据将在应许中，例如

In my case I was using Express. After I installed cors for Express and configured it and removed mode: "no-cors", I was returned a promise. The response data will be in the promise, e.g.

fetch('http://example.com/api/node', {
  // mode: 'no-cors',
  method: 'GET',
  headers: {
    Accept: 'application/json',
  },
},
).then(response => {
  if (response.ok) {
    response.json().then(json => {
      console.log(json);
    });
  }
});

这篇关于提取给出一个空的响应主体的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！