问题描述
我正在短暂轮询一个端点,直到准备好一些数据为止,我想最多重试该请求10次.
I am short polling an endpoint until some data is ready i would like to retry the request up to 10 times.
数据准备好后,我将收到一个非空数组200.
When the data is ready i recieve a 200 with a non-empty array.
我使用以下库 https://github.com/axios/axios https://github.com/softonic/axios-retry
try {
const axiosInstance = axios.create();
axiosInstance.interceptors.response.use((response) => {
if (response.data.metrics.length === 0) {
const error = new Error("Metrics Not Ready");
return Promise.reject(error);
}
return response;
}, (error) => {
return Promise.reject(error);
});
axiosRetry(axiosInstance, {
retries: 10,
retryCondition: (error) => {
console.log("RETRY CONDITION", error);
},
});
const metrics = await axiosInstance(options);
} catch (error) {
console.log(error);
}
我创建了一个axios拦截器,以检查数组的长度(如果0引发错误).但是,axiosRetry并没有抓住这一点,在这一点上我想重试该请求.相反,它被捕获在try catch块中并结束.
I have created an axios interceptor to check the length of the array if its 0 i am throwing an error. However this does not get caught by axiosRetry which at this point i want to retry the request. Instead it is being caught in the try catch block and ends.
推荐答案
您不需要axios-retry,只需要axios及其响应拦截器即可,并执行以下步骤:
You don't need axios-retry, all you need is axios and its response interceptor, with following steps:
- 检查数据是否为空.如果是,则抛出
axios.Cancel
错误.这将取消请求,调用错误处理程序而不是成功处理程序. - 在错误处理程序中,如果我们没有超过最大重试次数(在您的情况下为10),则重新发送HTTP请求.
- 继续执行第1步和第2步,直到获得数据或重试10次为止.
- Check whether data is empty. If yes, throw an
axios.Cancel
error. This would cancel the request, invoking error handler instead of success handler. - In the error handler, re-send the HTTP request if we haven't exceeded the maximum retry number (in your case, it is 10).
- Keep running step 1 and 2 until we get data or have retried 10 times.
代码如下:
const axios = require('axios');
const MAX_RETRY = 10;
let currentRetry = 0;
function successHandler() {
console.log('Data is Ready');
}
function errorHandler() {
if (currentRetry < MAX_RETRY) {
currentRetry++;
console.log('Retrying...');
sendWithRetry();
} else {
console.log('Retried several times but still failed');
}
}
function sendWithRetry() {
axios.get('http://example.com')
.then(successHandler).catch(errorHandler);
}
axios.interceptors.response.use(function (response) {
if (response.data.metrics.length) {
throw new axios.Cancel('Operation canceled by the user.');
} else {
return response;
}
}, function (error) {
return Promise.reject(error);
});
sendWithRetry();
不幸的是,对于axios-retry,当响应状态为200 OK
时,您无法重试HTTP请求,因为axios-retry使用axios.interceptors.response.use
,但对成功的响应"不执行任何操作.
For axios-retry, unfortunately you cannot retry HTTP request when response status is 200 OK
, as axios-retry uses axios.interceptors.response.use
but does nothing for "successful response".
这是axios-retry的源文件es/index.js
中的相应代码.您可以看到成功响应的拦截器是null
:
Here is the corresponding code in axios-retry's source file es/index.js
. You can see that the interceptor of successful response is null
:
export default function axiosRetry(axios, defaultOptions) {
axios.interceptors.request.use(config => {
const currentState = getCurrentState(config);
currentState.lastRequestTime = Date.now();
return config;
});
axios.interceptors.response.use(null, error => {
const config = error.config;
// If we have no information to retry the request
if (!config) {
return Promise.reject(error);
}
....
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