实现方案

在github找了很多开源项目，发现都比较陈旧，且在项目中不能直接使用，想自己手写这些解析不太现实，且时间也是不允许的，所以只能基于这些项目进行二次开发，并且整合到一起做通用方案，下面是项目中用到的一些预览库。

那么是如何把这些整合到一起实现的呢，准备好瓜子，听我细细分说！！！

入口文件

import React, { FC, useEffect } from 'react'; import styled, { ThemeProvider } from 'styled-components'; import { HeaderBar } from './components/HeaderBar'; import { ProxyRenderer } from './components/ProxyRenderer'; import CloudDocRenderer from './plugins/cloud-doc'; import { AppProvider } from './state'; import { defaultTheme } from './theme'; import { DocViewerProps } from './types'; import { IStyledProps } from './types'; import { DocViewerRenderers as pluginRenderers } from './plugins'; import { i18n, I18nextProvider } from './i18n'  const DocViewer: FC<DocViewerProps> = (props) => {   const { documents, theme, language } = props;    if (!documents || documents === undefined) {     throw new Error(       "Please provide an array of documents to DocViewer.ne.g. <DocViewer documents={[ { uri: 'https://mypdf.pdf' } ]} />"     );   }    useEffect(() => {       i18n.changeLanguage(language ?? 'zh');   }, [language]);    return (            <AppProvider pluginRenderers={pluginRenderers} {...props} >         <ThemeProvider theme={theme ? { ...defaultTheme, ...theme } : defaultTheme}>         <I18nextProvider i18n={i18n}>           <Container id="react-doc-viewer" data-testid="react-doc-viewer" {...props}>             <HeaderBar />             <ProxyRenderer />           </Container>           </I18nextProvider>         </ThemeProvider>       </AppProvider>   ); };     export default DocViewer;  const Container = styled.div`   display: flex;   flex-direction: column;   overflow: hidden;   background: ${(props: IStyledProps) => props.theme.bg_100};   height: 100%; `;  export { DocViewerRenderers } from './plugins'; export * from './types'; export * from './utils/fileLoaders'; export { default as BMPRenderer } from './plugins/bmp'; export { default as HTMLRenderer } from './plugins/html'; export { default as ImageProxyRenderer } from './plugins/image' export { default as JPGRenderer } from './plugins/jpg'; export { default as MSDocRenderer } from './plugins/ppt' export { default as MSGRenderer } from './plugins/msg'; export { default as PDFRenderer } from './plugins/png'; export { default as PNGRenderer } from './plugins/png'; export { default as TIFFRenderer } from './plugins/tiff'; export { default as TXTRenderer } from './plugins/txt'; export { default as CloudDocRenderer } from './plugins/cloud-doc';

从我们的入口文件可以看出，这里的有很多文件类型的render组件，分别处理不同的类型文件，具体实现我后面会讲到，必传参数是documents就是我们需要预览的文件信息，那么我们这里需要做的是把render组件和documents文件信息做关联关系。

fetch请求获取文件信息

首先我们需要拿到当前的需要预览文件的信息，从我们的文件信息中拿到文件的线上地址，然后使用 fetch 方法发送一个 HEAD 请求到 documentURI。HEAD 请求只请求资源的头部信息，不获取实际的内容，从返回的content-type中获取到文件类型信息

 fetch(documentURI, { method: 'HEAD', signal }).then((response) => {     const contentTypeRaw = response.headers.get('content-type');     const contentTypes = contentTypeRaw?.split(';') || [];     let contentType = contentTypes.length ? contentTypes[0] : undefined;     handleCurrentDocument(contentType)  })

PDFRenderer.fileTypes = ['pdf', 'application/pdf'];

    const currenrRenderers: DocRenderer[] = [];     pluginRenderers?.map((r) => {       if (!currentDocument.fileType) return;       if (r.fileTypes.indexOf(currentDocument.fileType) >= 0 ) {         currenrRenderers = r;       }     });

import React, { FC, useCallback } from 'react'; import styled from 'styled-components'; import { setRendererRect } from '../state/actions'; import { useDocumentLoader } from '../hooks/useDocumentLoader'; import { useWindowSize } from '../hooks/useWindowSize'; import { DocumentNav } from './DocumentNav'; import NotRender from './NotRender';  export const ProxyRenderer: FC<{}> = () => {   const { state, dispatch, CurrentRenderer } = useDocumentLoader();   const { documents, documentLoading } = state;    const size = useWindowSize();    const containerRef = useCallback(     (node) => {       node && dispatch(setRendererRect(node?.getBoundingClientRect()));     },     // eslint-disable-next-line react-hooks/exhaustive-deps     [size]   );   const Contents = useCallback(() => {     if (!documents.length) {       return <div id="no-documents">{/* No Documents */}</div>;     } else {       return (         <>           <DocumentNav loading={documentLoading}>             {CurrentRenderer ? <CurrentRenderer mainState={state} /> : <NotRender />}           </DocumentNav>         </>       );     }   }, [CurrentRenderer, state]);    return (     <Container id="proxy-renderer" ref={containerRef}>       <Contents />     </Container>   ); };  const Container = styled.div`   display: flex;   flex: 1;   overflow-y: hidden;   height: calc(100% - 68px);   width: 100%; `;

import { renderAsync } from 'polaris-docx-preview';  const Container = styled.div`   width: 100%;   height: 100%;   overflow-y: auto; `  const MSDocRenderer: DocRenderer = ({ mainState: { currentDocument } }) => {    useEffect(() => {     const element = document.getElementById('doc-renderer');     if(element && currentDocument?.uri) {       fetch(currentDocument.uri).then((response) => {         let docData = response.blob();         renderAsync(docData, element)       })     }   }, [])   if (!currentDocument) return null;    return (     <Container id="doc-renderer">     </Container>   ); };

import FileViewer from 'polaris-offices-viewer';  const MSDocRenderer: DocRenderer = ({ mainState: { currentDocument } }) => {    if (!currentDocument) return null;    return (     <Container id="msdoc-renderer">       <FileViewer          filePath={currentDocument?.uri}         errorComponent={<>errorc错误</>}        />     </Container>   ); };

import { PDFAllPages } from './PDFAllPages'; import PDFSinglePage from './PDFSinglePage';  const PDFPages: FC<{}> = () => {   const {     state: { mainState, paginated },     dispatch,   } = useContext(PDFContext);   const { t } = useTranslation()    const currentDocument = mainState?.currentDocument || null;    useEffect(() => {     dispatch(setNumPages(initialPDFState.numPages));   }, [currentDocument]);    if (!currentDocument || currentDocument.fileData === undefined) return null;    return (     <DocumentPDF       file={currentDocument.fileData}       onLoadSuccess={({ numPages }) => dispatch(setNumPages(numPages))}       loading={<span>{t('loading')}...</span>}>       {paginated ? <PDFSinglePage /> : <PDFAllPages />}     </DocumentPDF>   ); };

import React, { FC, useContext } from 'react'; import { Page } from 'react-pdf'; import styled from 'styled-components'; import { IStyledProps } from '../../../../types'; import { PDFContext } from '../../state'; import { useTranslation } from 'react-i18next';  interface Props {   pageNum?: number; }  const PDFSinglePage: FC<Props> = (props) => {   const { pageNum } = props;    const { t } = useTranslation()    const {     state: { mainState, paginated, zoomLevel, numPages, currentPage },   } = useContext(PDFContext);    const rendererRect = mainState?.rendererRect || null;    const _pageNum = pageNum || currentPage;   const defaultWidth = rendererRect?.width || 100;   const width = defaultWidth > 940 ? 940 : rendererRect?.width;    return (     <PageWrapper id="pdf-page-wrapper" last={_pageNum >= numPages}>       {!paginated && (         <PageTag id="pdf-page-info">           {t('page')} {_pageNum}/{numPages}         </PageTag>       )}       <Page         pageNumber={_pageNum || currentPage}         scale={zoomLevel}         height={(rendererRect?.height || 100) - 100}         width={width}       />     </PageWrapper>   ); };

import React, { FC, useContext } from 'react'; import { PDFContext } from '../../state'; import PDFSinglePage from './PDFSinglePage';  interface Props {   pageNum?: number; }  export const PDFAllPages: FC<Props> = (props) => {   const {     state: { numPages },   } = useContext(PDFContext);    const PagesArray = [];   for (let i = 0; i < numPages; i++) {     PagesArray.push(<PDFSinglePage key={i + 1} pageNum={i + 1} />);   }    return <>{PagesArray}</>; };

import styled from "styled-components"; import Artplayer from 'artplayer'; import type { DocRenderer } from "../..";  const VideoRenderer: DocRenderer = ({ mainState: { currentDocument, language } }) => {   useEffect(() => {     const lang = language === 'zh' ? 'zh-cn' : language     var art = new Artplayer({       container: '#video-renderer',       url: currentDocument?.uri || '',       volume: 0.5,       lang   });   art.on('click', (event) => {     console.info('click', event); });   art.on('screenshot', (dataUri) => {     art.screenshot();   });    }, [])   if (!currentDocument) return null;    return (     <Container className="video-renderer">       <div id='video-renderer'>       </div>     </Container>   ); };