Question

我使用whatwg-fetch发出请求，并且我正在尝试检查response.status === 0以防response.ok为false，以查看服务器当前是否处于脱机状态并相应地通知用户。

问题是，当服务器脱机时，response.status始终为200，response.ok始终为真。

const interpretJsonResponse = (response, callback):object => {
    const responseClone = response.clone();
    if (response.ok) {
        response.json().then((json) => callback(null, respondJson(json))).catch(callback);
    } else {
        //  Response is not ok. Callback with a generic error to show to the user
        //  and log the error for detailed info
        if (response.status === 0) {
            //  Backend server is not up
            callback('Backend server is not responding. Please retry later!');
        } else {
            callback(`Error in request: ${response.statusText}`);
        }
    }

    // Return a clone to allow usage of .json() again if necessary
    return responseClone;
};

由于缺少要回复的服务器，因为响应为空，我也收到了JSON解析错误。我/我可以缺少什么？

示例响应对象：

"url":"http://localhost:8000/client_v1/auth/",
"status":200,
"statusText":"OK",
"headers": {}
"ok":true,
"body":{  
   "_readableState":{  
      "highWaterMark":16384,
      "buffer":[],
      "length":0, 
      "pipes":null,
      "pipesCount":0,
      "flowing":null,
      "ended":false,
      "endEmitted":false,
      "reading":false,
      "sync":false,
      "needReadable":true,
      "emittedReadable":false,
      "readableListening":false,
      "objectMode":false,
      "defaultEncoding":"utf8",
      "ranOut":false,
      "awaitDrain":0,
      "readingMore":false,
      "decoder":null,
      "encoding":null
  },
  "readable":true,
  "_events":{},
  "_writableState":{  
     "highWaterMark":16384,
     "objectMode":false,
     "needDrain":false,
     "ending":false,
     "ended":false,
     "finished":false,
     "decodeStrings":true,
     "defaultEncoding":"utf8",
     "length":0,
     "writing":false,
     "corked":0,
     "sync":true,
     "bufferProcessing":false,
     "writecb":null,
     "writelen":0,
     "buffer":[  

     ],
     "pendingcb":0,
     "prefinished":false,
     "errorEmitted":false
  },
  "writable":true,
  "allowHalfOpen":true,
  "_transformState":{  
     "needTransform":false,
     "transforming":false,
     "writecb":null,
     "writechunk":null
  }
},
"bodyUsed":false,
"size":0,
"timeout":0,
"_raw":[],
"_abort":false

编辑：添加完整功能编辑＃2：添加了示例whatwg-fetch响应对象

Answer 1

我刚刚在fetch中找到了这个警告，这可能对您有用：

Caveats

The fetch specification differs from jQuery.ajax() in mainly two ways that bear keeping in mind:

The Promise returned from fetch() won't reject on HTTP error status even if the response is a HTTP 404 or 500. Instead, it will resolve normally, and it will only reject on network failure, or if anything prevented the request from completing.

所以，我应该简单地检查响应是否为空（如果响应为空，如你所说）：

if (response === null) {
  return callback('Empty reponse from backend server. Please retry later!');
}
if (response.ok) {
  ...

whatwg-fetch response.ok ===即使服务器处于脱机状态也是如此

1 个答案: