在 React App 中使用 Axios 将响应数据下载为流

本文介绍了在 React App 中使用 Axios 将响应数据下载为流的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我需要通过将结果流式传输到 CSV 文件来从端点下载查询结果.这是为了支持一次通过浏览器发送大量 ResultSet.

I need to download query results from an endpoint by streaming results to a CSV file. This is in an effort to support enormous ResultSets being sent through the browser at one time.

有没有办法在 React 应用程序的上下文中使用 Axios 来实现这一点?

Is there a way to accomplish this using Axios in the context of a React App?

我见过 fetch() 并且知道它具有以下特点:

I have seen fetch() and know that it has the following characteristics:

返回可读流
IE11 不支持
不允许拦截请求
响应的状态与请求本身有关，与 HTTP 状态无关
- 这意味着接收错误的唯一方法是由于流提前结束而出现问题
- 这肯定对我不起作用，因为我有与用户权限相关的自定义错误处理
- returns ReadableStream
- Is NOT supported by IE11
- Does NOT allow for intercepting requests
- The status of a response relates to the request itself, not the HTTP status
  - This means that the only way to receive an error would be to have something go wrong with the stream ending prematurely
  - This definitely won't work for me since I have custom error-handling related to user permissions
  除了 ReadableStream 响应类型之外，列出的其余特征都是不允许的.我需要支持 IE11 并允许拦截请求/读取 HTTP 状态以确定如何处理流量.
  Besides the ReadableStream response type, the rest of the characteristics listed are not permissible. I will need to support IE11 and allow for intercepting requests / reading the HTTP status to determine how to handle the traffic.
```
      // The promise returned by `fetch` rejects if the fetch was unable to make HTTP-request
      //  e.g. network problems, or there’s no such site.
      // Abnormal HTTP-statuses, such as 404 or 500 do not cause an error.
      const results = await fetch(`${URL}/data`, {
        method: 'post', // HTTP POST to send query to server
        headers: {
          Accept: 'application/json, text/plain, */*', // indicates which files we are able to understand
          'Content-Type': 'application/json', // indicates what the server actually sent
        },
        body: JSON.stringify(query), // server is expecting JSON
        credentials: 'include', // sends the JSESSIONID cookie with the address
      }).then(res => res.json()) // turn the ReadableStream response back into JSON
        .then((res) => {
          if (res.ok) {
            // boolean, true if the HTTP status code is 200-299.
            console.log('response.ok!');
          } else if (res.status === 401) {
            throw Error(`You are not authenticated. Please login.`);
          } else if (res.status === 403) {
            throw Error(`You are not authorized to access this data.`);
          } else {
            throw Error(`Request rejected with status ${res.status}`);
          }
        })
        .catch((error) => {
          // catches error case and if fetch itself rejects
          error.response = {
            status: 0,
            statusText:
              'Cannot connect. Please make sure you are connected to internet.',
          };
          throw error;
        });

      console.log(results);
```
  axios 的示例(非流媒体)
  Axios 实例
```
import ...
const Api = axios.create({
  baseURL: `${URL}`,
  withCredentials: true,
});

// attach interceptors to requests and responses
// these are defined elsewhere and imported
Api.interceptors.request.use((request) => requestHandler(request));
Api.interceptors.response.use((response) => successHandler(response), (error) => errorHandler(error));

export default Api;
```
  axios 请求
```
const query = {"selections":{"TABLE_A":["COLUMN1"]},"filters":[{"predicates":[]}],"joins":[],"sorts":[],"limit":100,"offset":0}
const response = await Api.post('/data', query);
// further transformations to response to get formatted csv results required
```
  关于 Axios 的问题
  - 是否可以在 Axios 中拥有与 fetch 相同的 ReadableStream?
  - 仅当假设 Node 在仅服务器端设置中支持它时，才可以在 Axios 中进行流式传输吗?
    - this 等网站似乎在说使用 responseType: 'stream' 不是可以在浏览器中完成的事情，只能在 Node.js 中使用 fs

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