相关疑难解决方法(0)

我有一个HTTP API,它在成功和失败时返回JSON数据.

示例失败将如下所示:

~ ? http get http://localhost:5000/api/isbn/2266202022 
HTTP/1.1 400 BAD REQUEST
Content-Length: 171
Content-Type: application/json
Server: TornadoServer/4.0

{
    "message": "There was an issue with at least some of the supplied values.", 
    "payload": {
        "isbn": "Could not find match for ISBN."
    }, 
    "type": "validation"
}

我想在JavaScript代码中实现的是这样的:

fetch(url)
  .then((resp) => {
     if (resp.status >= 200 && resp.status < 300) {
       return resp.json();
     } else {
       // This does not work, since the Promise returned by `json()` is never fulfilled
       return Promise.reject(resp.json()); …

我正在尝试使用fetch和ES6 promises智能地处理来自API的成功/错误响应.

以下是我需要处理响应状态的方法:

204: has no json response, but need to treat as success
406: should redirect to sign in
422: has json for error message
< 400 (but not 204): success, will have json
>= 400 (but not 422): error, will not have json

所以,我正在努力学习如何干净利落地写这个.

我现在有一些不太常用的代码,看起来像这样:

fetch()
  .then(response => checkStatus(response))
  .then(parseJSON)                           //will throw for the 204
  .then(data => notify('success', someMsg))
  .catch(error => checkErrorStatus(error))
  .then(parseJSON)
  .then(data => notify('error', dataForMsg)
  .catch(error => notify('error', someGenericErrorMsg)

但是使用catch两次似乎很奇怪,我还不知道如何处理204.

另外,只是澄清checkStatus并checkErrorStatus做类似的事情:

export …