Axios 拦截器重试发送FormData

Question

I'm trying to create a "retry" functionality for a request containing a FormData as data. The retry happen when the JWT token is expired, my second request (the retry one) doesn't contain any data.

The idea:

const axiosInstance = axios.create();

  /**
   * Before each request, we'll add a possible retry if the
   * request need a refreshed token
   */
  axiosInstance.interceptors.request.use((request) => {
    if (typeof _.get(request, ['retried']) === 'undefined') {
      request.retried = false;
    }

    return request;
  });

/**
   * After a request with an error, we'll check if the error is a token not refreshed.
   * If we didn't already tried to refresh, we'll just fallback to the errorHandler function
   */
  axiosInstance.interceptors.response.use(null, async (error) => {
    const statusCode = _.get(error, ['response', 'data', 'statusCode']);
    const message = _.get(error, ['response', 'data', 'message']);
    const { config: request = {} } = error;

    if (statusCode === 401 && !request.retried) {
      try {
        const newTokens = await refreshTokens();
        request.retried = true;
        _.set(request, ['headers', 'authorization'], newTokens.accessToken);
        return axiosInstance.request(request);
      } catch (e) {
        return error;
      }
    }
    return error;
  });

The request:

  const formData = new FormData();
  formData.append('name', name);
  formData.append('file', fs.createReadStream(file.path));

  axiosInstance.post(
      'http://localhost/upload',
      formData,
      {
        headers: {
          ...formData.getHeaders(),
          authorization: tokens.accessToken
        }
      }
    );

If my token expired, the request will fail, the interceptor will then refresh my tokens, and retry the exact same request with just the new header Authorization . Yet, on the server side, the received payload is always null.

Answer 1

As far as I know, the formData needs to be added again on the retry (I think it is due to the data being added as a stream and consumed during the request, so a new retry cannot consume the already consumed stream).

You can take a look at request.data to see what I mean.

Answer 2

You can pass the form data within the config parameter:

axiosInstance.post(
  'http://localhost/upload',
  {},
  {
    data: formData, // <---- pass it here
    headers: {
      ...formData.getHeaders(),
      authorization: tokens.accessToken
    }
  }
);