首页确保项目中使用了axios
axios ondownloadprogress中total总为零，content-length不返回?
点我查看 Axios Documention
npm i axios
yarn add axios
以下我们举例接口调用配置说明：
由于接口下载时，不确定文件下载时长，所以直接设置不限时
timeout: -1,
由于 axios 已提供下载与上传的回掉函数（callback），所以我们直接调用就好
import { useState } from "react"type ProgressStatusType = "normal" | "active" | "success" | "exception"interface TestReportState {showProgressModal: booleandownloadPercent: numberdownloadStatus: ProgressStatusType
}const [showProgressModal,setShowProgressModal] = useState<boolean>(false)
const [downloadPercent,setDownloadPercent] = useState<number>(0)
const [downloadStatus,setDownloadStatus] = useState<ProgressStatusType>("normal")// 外层调用
const downloadFile = async (filename: string): Promise<void> => {try {setShowProgressModal(true)setDownloadStatus("active")const res = await downLoadFileTemp({ filename }, state)setDownloadStatus("success")downloadFileAction(filename, res)} catch (error) {setDownloadStatus("exception")console.error("downloadFile->", error)}
}export const downLoadFile = (params: { filename: string }, setDownloadPercent:()=>void ): Promise<Blob> => {return get(`api/getFile?${qs.stringify(params)}`, {timeout: -1, // 不限时onDownloadProgress: (progressEvent: ProgressEvent) => {setDownloadPercent(calcProgress(progressEvent)) },onUploadProgress: (progressEvent: ProgressEvent) => {// Do whatever you want with the Axios progress event},})
}
为了提高代码互用性与可维护性所以将计算进度的逻辑做了封装
/*** 计算进度条百分比*/
export const calcProgress = (progressEvent: ProgressEvent): number => {const { loaded = 0, total = 0 } = progressEvent || {}return Math.ceil((loaded / total) * 100) || 0
}
你可能有疑惑 progressEvent 中所含有的字段，请看以下示例：
/*** Events measuring progress of an underlying process, like an HTTP request (for an XMLHttpRequest, or the loading of the underlying resource of an <img>, <audio>, <video>, <style> or <link>).** [MDN Reference](https://developer.mozilla.org/docs/Web/API/ProgressEvent)*/
interface ProgressEvent<T extends EventTarget = EventTarget> extends Event {/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/ProgressEvent/lengthComputable) */readonly lengthComputable: boolean;/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/ProgressEvent/loaded) */readonly loaded: number;readonly target: T | null;/** [MDN Reference](https://developer.mozilla.org/docs/Web/API/ProgressEvent/total) */readonly total: number;
}
axios ondownloadprogress中total总为零，content-length不返回?
- 后端在header中加上content-length
- 如果使用了Gzip做了文件分块获取到的 content-length 也可能是不准确的，所以可以让后端将此信息新建一个字段解决 例如：
response header {...custom-content-length: 2040
}
)
)
