我有一个fetch-api POST请求:

fetch(url, {
  method: 'POST',
  body: formData,
  credentials: 'include'
})

我想知道这个的默认超时时间是多少?我们如何将它设置为特定的值,比如3秒或不定秒?


当前回答

一个更简单的方法是在MDN中:https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal#aborting_a_fetch_operation_with_a_timeout

try {
    await fetch(url, { signal: AbortSignal.timeout(5000) });
} catch (e) {
    if (e.name === "TimeoutError") {
        console.log('5000 ms timeout');
    }
}

其他回答

  fetchTimeout (url,options,timeout=3000) {
    return new Promise( (resolve, reject) => {
      fetch(url, options)
      .then(resolve,reject)
      setTimeout(reject,timeout);
    })
  }

使用AbortController和setTimeout;

const abortController = new AbortController();

let timer: number | null = null;

fetch('/get', {
    signal: abortController.signal, // Content to abortController
})
    .then(res => {
        // response success
        console.log(res);

        if (timer) {
            clearTimeout(timer); // clear timer
        }
    })
    .catch(err => {
        if (err instanceof DOMException && err.name === 'AbortError') {
            // will return a DOMException
            return;
        }

        // other errors
    });

timer = setTimeout(() => {
    abortController.abort();
}, 1000 * 10); // Abort request in 10s.

这是@fatcherjs/middleware-aborter中的一个片段。

通过使用fatcher,可以很容易地中止取回请求。

import { aborter } from '@fatcherjs/middleware-aborter';
import { fatcher, isAbortError } from 'fatcher';

fatcher({
    url: '/bar/foo',
    middlewares: [
        aborter({
            timeout: 10 * 1000, // 10s
            onAbort: () => {
                console.log('Request is Aborted.');
            },
        }),
    ],
})
    .then(res => {
        // Request success in 10s
        console.log(res);
    })
    .catch(err => {
        if (isAbortError(err)) {
            //Run error when request aborted.
            console.error(err);
        }

        // Other errors.
    });

一个更简单的方法是在MDN中:https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal#aborting_a_fetch_operation_with_a_timeout

try {
    await fetch(url, { signal: AbortSignal.timeout(5000) });
} catch (e) {
    if (e.name === "TimeoutError") {
        console.log('5000 ms timeout');
    }
}

您可以创建一个timeoutPromise包装器

function timeoutPromise(timeout, err, promise) {
  return new Promise(function(resolve,reject) {
    promise.then(resolve,reject);
    setTimeout(reject.bind(null,err), timeout);
  });
}

然后可以包装任何承诺

timeoutPromise(100, new Error('Timed Out!'), fetch(...))
  .then(...)
  .catch(...)  

它实际上不会取消底层连接,但允许您超时承诺。 参考

正确的错误处理技巧


正常的做法:

为了在大多数情况下增加超时支持,建议引入一个Promise实用函数,如下所示:

function fetchWithTimeout(resource, { signal, timeout, ...options } = {}) {
  const controller = new AbortController();
  if (signal != null) signal.addEventListener("abort", controller.abort);
  const id = timeout != null ? setTimeout(controller.abort, timeout) : undefined;
  return fetch(resource, {
    ...options,
    signal: controller.signal
  }).finally(() => {
    if (id != null) clearTimeout(id);
  });
}

调用控制器。abort或拒绝setTimeout回调函数中的承诺会扭曲堆栈跟踪。

这是次优的,因为如果需要对错误后日志进行分析,就必须在调用fetch方法的函数中添加带有日志消息的样板错误处理程序。


好专业知识:

为了保留错误及其堆栈跟踪,可以应用以下技术:

function sleep(ms = 0, signal) { return new Promise((resolve, reject) => { const id = setTimeout(() => resolve(), ms); signal?.addEventListener("abort", () => { clearTimeout(id); reject(); }); }); } async function fetch( resource, options ) { const { timeout, signal, ...ropts } = options ?? {}; const controller = new AbortController(); let sleepController; try { signal?.addEventListener("abort", () => controller.abort()); const request = nodeFetch(resource, { ...ropts, signal: controller.signal, }); if (timeout != null) { sleepController = new AbortController(); const aborter = sleep(timeout, sleepController.signal); const race = await Promise.race([aborter, request]); if (race == null) controller.abort(); } return request; } finally { sleepController?.abort(); } } (async () => { try { await fetchWithTimeout(new URL(window.location.href), { timeout: 5 }); } catch (error) { console.error("Error in test", error); } })();