【vue3】实现pdf在线预览的几种方式

今天一天对当前可用的pdf预览插件做了测试，主要需求是只能预览不能下载，但对于前端来说，没有绝对的禁止，这里只罗列实现方式。
目前采用vue3版本为：3.2.37

1. iframe
2. vue-office
3. pdfjs-dist

iframe

先说最简单的，iframe可以直接展示pdf文件，所以如果不作禁止预览等操作，iframe是最合适的。

    <el-dialog
      v-model="previewOtherUpload"
      reset-drag-position
      draggable
      sticky
      :title="_options.imgName || '详情'"
      footer-hide
      class-name="vertical-center-modal"
    >
        <div
          @contextmenu.prevent
          style="user-select: none;"
        >
          <iframe
            ref="iframe"
            :src="`${modelValue}#toolbar=0`"
            width="100%"
            height="600px"
            @load="onIframeLoad"
          >
          </iframe>
        </div>
    </el-dialog>

<script setup>
const modelValue = ref('https://501351981.github.io/vue-office/examples/dist/static/test-files/test.pdf')
let previewOtherUpload = ref(false);
const iframe = ref(null)

const clickShow = () => {
	previewOtherUpload.value = true;
}

// 尝试在iframe加载完毕后，进行右键禁用，但实际需要通过postmessage来处理，所以这里无实际用处
const onIframeLoad = () => {
  try {
    console.log('iframe 已加载', iframe.value.contentWindow.window);
    if (iframe.value.contentWindow.document) {
      iframe.value.contentWindow.document.addEventListener('contextmenu', (e) => e.preventDefault());
    }
  } catch (error) {
    console.error('无法访问 iframe 内容:', error);
  }
}
</script>

vue-office

vue-office-gitcode地址

安装
#docx文档预览组件
npm install @vue-office/docx vue-demi@0.14.6

#excel文档预览组件
npm install @vue-office/excel vue-demi@0.14.6

#pdf文档预览组件
npm install @vue-office/pdf vue-demi@0.14.6

#pptx文档预览组件
npm install @vue-office/pptx vue-demi@0.14.6

如果是vue2.6版本或以下还需要额外安装 @vue/composition-api
npm install @vue/composition-api

我们如果只预览pdf，则安装 npm install @vue-office/pdf vue-demi@0.14.6

    <el-dialog
      v-model="previewOtherUpload"
      reset-drag-position
      draggable
      sticky
      :title="_options.imgName || '详情'"
      footer-hide
      class-name="vertical-center-modal"
    >
        <div
          @contextmenu.prevent
          style="user-select: none;"
        >
          <VueOfficePdf
            :src="modelValue"
          />
        </div>
    </el-dialog>

<script setup>
import VueOfficePdf from '@vue-office/pdf'
const modelValue = ref('https://501351981.github.io/vue-office/examples/dist/static/test-files/test.pdf')
let previewOtherUpload = ref(false);

const clickShow = () => {
	previewOtherUpload.value = true;
}
</script>

pdfjs-dist

这是目前最麻烦的一个插件，一定先确定下载的版本"pdfjs-dist": “2.16.105”，我用的是这个，否则下面的workerSrc设置会有问题。

  <el-dialog
      v-model="previewOtherUpload"
      reset-drag-position
      draggable
      sticky
      :title="_options.imgName || '详情'"
      footer-hide
      class-name="vertical-center-modal"
    >
		<div 
          id="pdf-view"
          @contextmenu.prevent
          style="user-select: none;"
        >
            <canvas v-for="page in state.pdfPages" :key="page" id="pdfCanvas" />
            <div id="text-view"></div>
        </div>
    </el-dialog>

<script setup>
import { computed, reactive, ref, watch, nextTick } from "vue";
import * as pdfjsViewer from 'pdfjs-dist/web/pdf_viewer.js'
import 'pdfjs-dist/web/pdf_viewer.css'
import * as PDF from 'pdfjs-dist'
// 设置 pdf.worker.js 路径
PDF.GlobalWorkerOptions.workerSrc = '../../../node_modules/pdfjs-dist/build/pdf.worker.js';
let pdfDoc = null;

const modelValue = ref('https://501351981.github.io/vue-office/examples/dist/static/test-files/test.pdf')
let previewOtherUpload = ref(false);

const clickShow = () => {
	loadFile(modelValue)
	previewOtherUpload.value = true;
}

const loadFile = (url) => {
    PDF.getDocument({
        url,
        cMapUrl: 'https://cdn.jsdelivr.net/npm/pdfjs-dist@2.16.105/cmaps/',
        cMapPacked: true,
    }).promise.then((pdf) => {
        pdfDoc = pdf
        // 获取pdf文件总页数
        state.pdfPages = pdf.numPages
        nextTick(() => {
            renderPage(1) // 从第一页开始渲染
        })
    })
}
const renderPage = (num) => {
    pdfDoc.getPage(num).then((page) => {
        const canvas = document.getElementById('pdfCanvas')
        const ctx = canvas.getContext('2d')
        const viewport = page.getViewport({ scale: state.pdfScale })
        canvas.width = viewport.width
        canvas.height = viewport.height
        const renderContext = {
            canvasContext: ctx,
            viewport
        }
        page.render(renderContext)
    })
}
</script>

插件样式也不好调整，不推荐。

总结：
最后还是使用了第二种方式，作为禁止下载的展示。