AXIOS：如何并发运行http请求并在请求失败时获取所有请求事件的结果

Question

我试图让服务器同时获取请求，为了做到这一点，我编写了以下函数。

问题

如果单个调用失败，那么我将无法获得其余请求的响应。

export const getAll = async (collection) => {
    return new Promise((resolve, reject) => {
        const requests = collection.map(req => {
            const config = {
                headers: req.headers,
                params: req.params
            }
            return axios.get(req.url, config);
        })

        axios.all(requests)
            .then(axios.spread((...args) => {
                // all succerss
                resolve(args);
            }))
            .catch(function (error) {
                // single call fails and all calls are lost
                reject(error)
            });
    })
}

是否有可能获得所有请求的结果，无论失败还是成功？

Answer 1

换句话说，即使请求失败，您也希望像请求成功一样执行其余代码。

让我们假设 response 不能为null 。 然后我们捕获请求的错误并在这种情况下为请求返回null 。

export const getAll = async (collection) => {
    const requests = collection.map(req => {
        const config = {
            headers: req.headers,
            params: req.params
        };
        return axios.get(req.url, config).catch(() => null);
    })
    return axios.all(requests);
}

因此，如果您有catch()并且它没有抛出异常，则所有后续代码都可以像 Promise 一样工作，而不是被拒绝。

另请注意，您不需要从async函数显式返回Promise ，因为它会自动发生。 甚至更多：由于您在函数内没有await您实际上不需要将其标记为async 。 最后axios.all返回Promise因此您无需手动resolve / reject Promise。

Answer 2

我过去这样做的方法是将我的承诺的返回值包装到一个对象中，该对象具有一个result字段或类似的内容和一个err字段：

export const getAll = async (collection) => {
    const requests = collection.map(req => {
        const config = {
            headers: req.headers,
            params: req.params
        }

        return axios.get(req.url, config)
            //wrap all responses into objects and always resolve
            .then(
                (response) => ({ response }),
                (err) => ({ err })
            );
    });

    return axios.all(requests)
        //note that .then(axios.spread((...args) => {}) is the same as not using
        //spread at all: .then((args) => {})
        .then(axios.spread((...args) => {
            //getAll will resolve with a value of
            //[{ response: {}, err: null }, ...]

            return args;
        }))
        .catch((err) => {
            //this won't be executed unless there's an error in your axios.all
            //.then block

            throw err;
        });
}

另请参阅@skyboyer 的帖子，了解他对您的其余代码提出的一些优点。

Answer 3

以下是基于 Andrew 解决方案的完整基于 node js 的示例：

const axios = require('axios');

const getAll = async (collection) => {
    const requests = collection.map(req => {
        const config = {
            // headers: req.headers,
            params: req.params
        }

        return axios.get(req.url, config)
        //wrap all responses into objects and always resolve
            .then(
                (apiResponse) => ({
                    apiResponse
                }),
                (apiError) => ({
                    apiError
                })
            );
    });

    return axios.all(requests)
    //note that .then(axios.spread((...args) => {}) is the same as not using
    //spread at all: .then((args) => {})
        .then(axios.spread((...args) => {
            //getAll will resolve with a value of
            //[{ response: {}, err: null }, ...]

            return args;
        }))
        .catch((axiosError) => {
            //this won't be executed unless there's an error in your axios.all
            //.then block

            throw axiosError;
        });
}

let api1 = {url: "http://localhost:3000/test?id=1001", param: ""};
let api2 = {url: "http://localhost:3000/test?id=1002", param: ""};
let api3 = {url: "http://localhost:3000/test?id=1003", param: ""};
let apis = [api1, api2, api3];

getAll(apis).then((res) => {
        console.log("getAll call finished");
        //console.log(res);
    }
);