Windows Cordova 应用程序：应用程序无法在本地上下文中加载远程 Web 内容

Question

我有一个 UWP cordova 应用程序，它使用 PDFJS 来呈现 pdf 文件。它将嵌入字体加载为 data-uri，但我收到错误 An app can’t load remote web content in the local context. 以及警告 Warning: Load test font never loaded.。我想做的是这样的，但在 UWP 应用程序中：https://mozilla.github.io/pdf.js/web/viewer.html

这是加载字体的代码（在 pdf.js 7390 行附近找到）：

    data = spliceString(data, CFF_CHECKSUM_OFFSET, 4, (0, _util.string32)(checksum));
    var url = 'url(data:font/opentype;base64,' + btoa(data) + ');';
    var rule = '@font-face { font-family:"' + loadTestFontId + '";src:' + url + '}';

一个这样的场景： @font-face { font-family:"g_d0_f9"; src:url(data:font/opentype;base64,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)

有什么方法可以加载文件吗？

文件夹结构：

index.html

main.js

pdf-js/

cmaps/

images/

locale/

compatibility.js

l10n.js

pdf.js

pdf.worker.js

viewer.css

viewer.js

Index.html（此处包含的标记摘自 viewer.html）

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <link href="pdf-js/viewer.css" type="text/css" rel="stylesheet" />
  <script type="text/javascript" src="js/compatibility.js"></script>
  <link rel="resource" type="application/l10n" href="pdf-js/locale/locale.properties">
  <script type="text/javascript" src="pdf-js/l10n.js"></script>
  <script type="text/javascript" src="pdf-js/pdf.js"></script>
  <script type="text/javascript" src="pdf-js/pdf.worker.js"></script>
  <script type="text/javascript" src="pdf-js/viewer.js"></script>
  <script type="text/javascript" src="main.js"></script>
</head>
<body>
  <div id="pdf-viewer">
    <div id="outerContainer">
        <div id="sidebarContainer">
            <div id="toolbarSidebar">
                <div class="splitToolbarButton toggled">
                    <button id="viewThumbnail" class="toolbarButton group toggled" title="Show Thumbnails" tabindex="2" data-l10n-id="thumbs">
                        <span data-l10n-id="thumbs_label">Thumbnails</span>
                    </button>
                    <button id="viewOutline" class="toolbarButton group" title="Show Document Outline (double-click to expand/collapse all items)" tabindex="3" data-l10n-id="document_outline">
                        <span data-l10n-id="document_outline_label">Document Outline</span>
                    </button>
                    <button id="viewAttachments" class="toolbarButton group" title="Show Attachments" tabindex="4" data-l10n-id="attachments">
                        <span data-l10n-id="attachments_label">Attachments</span>
                    </button>
                </div>
            </div>
            <div id="sidebarContent">
                <div id="thumbnailView">
                </div>
                <div id="outlineView" class="hidden">
                </div>
                <div id="attachmentsView" class="hidden">
                </div>
            </div>
        </div>  <!-- sidebarContainer -->

        <div id="mainContainer">
            <div class="findbar hidden doorHanger hiddenSmallView" id="findbar">
                <label for="findInput" class="toolbarLabel" data-l10n-id="find_label">Find:</label>
                <input id="findInput" class="toolbarField" tabindex="91">
                <div class="splitToolbarButton">
                    <button class="toolbarButton findPrevious" title="" id="findPrevious" tabindex="92" data-l10n-id="find_previous">
                        <span data-l10n-id="find_previous_label">Previous</span>
                    </button>
                    <div class="splitToolbarButtonSeparator"></div>
                    <button class="toolbarButton findNext" title="" id="findNext" tabindex="93" data-l10n-id="find_next">
                        <span data-l10n-id="find_next_label">Next</span>
                    </button>
                </div>
                <input type="checkbox" id="findHighlightAll" class="toolbarField" tabindex="94">
                <label for="findHighlightAll" class="toolbarLabel" data-l10n-id="find_highlight">Highlight all</label>
                <input type="checkbox" id="findMatchCase" class="toolbarField" tabindex="95">
                <label for="findMatchCase" class="toolbarLabel" data-l10n-id="find_match_case_label">Match case</label>
                <span id="findResultsCount" class="toolbarLabel hidden"></span>
                <span id="findMsg" class="toolbarLabel"></span>
            </div>  <!-- findbar -->

            <div id="secondaryToolbar" class="secondaryToolbar hidden doorHangerRight">
                <div id="secondaryToolbarButtonContainer">
                    <button id="secondaryPresentationMode" class="secondaryToolbarButton presentationMode visibleLargeView hidden" title="Switch to Presentation Mode" tabindex="51" data-l10n-id="presentation_mode">
                        <span data-l10n-id="presentation_mode_label">Presentation Mode</span>
                    </button>

                    <button id="secondaryOpenFile" class="secondaryToolbarButton openFile visibleLargeView hidden" title="Open File" tabindex="52" data-l10n-id="open_file">
                        <span data-l10n-id="open_file_label">Open</span>
                    </button>

                    <button id="secondaryPrint" class="secondaryToolbarButton print visibleMediumView" title="Print" tabindex="53" data-l10n-id="print">
                        <span data-l10n-id="print_label">Print</span>
                    </button>

                    <button id="secondaryDownload" class="secondaryToolbarButton download visibleMediumView hidden" title="Download" tabindex="54" data-l10n-id="download">
                        <span data-l10n-id="download_label">Download</span>
                    </button>

                    <a href="#" id="secondaryViewBookmark" class="secondaryToolbarButton bookmark visibleSmallView hidden" title="Current view (copy or open in new window)" tabindex="55" data-l10n-id="bookmark">
                        <span data-l10n-id="bookmark_label">Current View</span>
                    </a>

                    <div class="horizontalToolbarSeparator visibleLargeView"></div>

                    <button id="firstPage" class="secondaryToolbarButton firstPage" title="Go to First Page" tabindex="56" data-l10n-id="first_page">
                        <span data-l10n-id="first_page_label">Go to First Page</span>
                    </button>
                    <button id="lastPage" class="secondaryToolbarButton lastPage" title="Go to Last Page" tabindex="57" data-l10n-id="last_page">
                        <span data-l10n-id="last_page_label">Go to Last Page</span>
                    </button>

                    <div class="horizontalToolbarSeparator"></div>

                    <button id="pageRotateCw" class="secondaryToolbarButton rotateCw" title="Rotate Clockwise" tabindex="58" data-l10n-id="page_rotate_cw">
                        <span data-l10n-id="page_rotate_cw_label">Rotate Clockwise</span>
                    </button>
                    <button id="pageRotateCcw" class="secondaryToolbarButton rotateCcw" title="Rotate Counterclockwise" tabindex="59" data-l10n-id="page_rotate_ccw">
                        <span data-l10n-id="page_rotate_ccw_label">Rotate Counterclockwise</span>
                    </button>

                    <div class="horizontalToolbarSeparator"></div>

                    <button id="toggleHandTool" class="secondaryToolbarButton handTool" title="Enable hand tool" tabindex="60" data-l10n-id="hand_tool_enable">
                        <span data-l10n-id="hand_tool_enable_label">Enable hand tool</span>
                    </button>

                    <div class="horizontalToolbarSeparator"></div>

                    <button id="documentProperties" class="secondaryToolbarButton documentProperties" title="Document Properties…" tabindex="61" data-l10n-id="document_properties">
                        <span data-l10n-id="document_properties_label">Document Properties…</span>
                    </button>
                </div>
            </div>  <!-- secondaryToolbar -->

            <div class="toolbar">
                <div id="toolbarContainer">
                    <div id="toolbarViewer">
                        <div id="toolbarViewerLeft">
                            <button id="sidebarToggle" class="toolbarButton" title="Toggle Sidebar" tabindex="11" data-l10n-id="toggle_sidebar">
                                <span data-l10n-id="toggle_sidebar_label">Toggle Sidebar</span>
                            </button>
                            <div class="toolbarButtonSpacer"></div>
                            <button id="viewFind" class="toolbarButton group hiddenSmallView" title="Find in Document" tabindex="12" data-l10n-id="findbar">
                                <span data-l10n-id="findbar_label">Find</span>
                            </button>
                            <div class="splitToolbarButton">
                                <button class="toolbarButton pageUp" title="Previous Page" id="previous" tabindex="13" data-l10n-id="previous">
                                    <span data-l10n-id="previous_label">Previous</span>
                                </button>
                                <div class="splitToolbarButtonSeparator"></div>
                                <button class="toolbarButton pageDown" title="Next Page" id="next" tabindex="14" data-l10n-id="next">
                                    <span data-l10n-id="next_label">Next</span>
                                </button>
                            </div>
                            <input type="number" id="pageNumber" class="toolbarField pageNumber" title="Page" value="1" size="4" min="1" tabindex="15" data-l10n-id="page">
                            <span id="numPages" class="toolbarLabel"></span>
                        </div>
                        <div id="toolbarViewerRight">
                            <button id="presentationMode" class="toolbarButton presentationMode hiddenLargeView hidden" title="Switch to Presentation Mode" tabindex="31" data-l10n-id="presentation_mode">
                                <span data-l10n-id="presentation_mode_label">Presentation Mode</span>
                            </button>

                            <button id="openFile" class="toolbarButton openFile hiddenLargeView hidden" title="Open File" tabindex="32" data-l10n-id="open_file">
                                <span data-l10n-id="open_file_label">Open</span>
                            </button>

                            <button id="print" class="toolbarButton print hiddenMediumView" title="Print" tabindex="33" data-l10n-id="print">
                                <span data-l10n-id="print_label">Print</span>
                            </button>

                            <button id="download" class="toolbarButton download hiddenMediumView hidden" title="Download" tabindex="34" data-l10n-id="download">
                                <span data-l10n-id="download_label">Download</span>
                            </button>
                            <a href="#" id="viewBookmark" class="toolbarButton bookmark hiddenSmallView hidden" title="Current view (copy or open in new window)" tabindex="35" data-l10n-id="bookmark">
                                <span data-l10n-id="bookmark_label">Current View</span>
                            </a>

                            <div class="verticalToolbarSeparator hiddenSmallView"></div>

                            <button id="secondaryToolbarToggle" class="toolbarButton" title="Tools" tabindex="36" data-l10n-id="tools">
                                <span data-l10n-id="tools_label">Tools</span>
                            </button>
                        </div>
                        <div id="toolbarViewerMiddle">
                            <div class="splitToolbarButton">
                                <button id="zoomOut" class="toolbarButton zoomOut" title="Zoom Out" tabindex="21" data-l10n-id="zoom_out">
                                    <span data-l10n-id="zoom_out_label">Zoom Out</span>
                                </button>
                                <div class="splitToolbarButtonSeparator"></div>
                                <button id="zoomIn" class="toolbarButton zoomIn" title="Zoom In" tabindex="22" data-l10n-id="zoom_in">
                                    <span data-l10n-id="zoom_in_label">Zoom In</span>
                                </button>
                            </div>
                            <span id="scaleSelectContainer" class="dropdownToolbarButton">
                                <select id="scaleSelect" title="Zoom" tabindex="23" data-l10n-id="zoom">
                                    <option id="pageAutoOption" title="" value="auto" selected="selected" data-l10n-id="page_scale_auto">Automatic Zoom</option>
                                    <option id="pageActualOption" title="" value="page-actual" data-l10n-id="page_scale_actual">Actual Size</option>
                                    <option id="pageFitOption" title="" value="page-fit" data-l10n-id="page_scale_fit">Fit Page</option>
                                    <option id="pageWidthOption" title="" value="page-width" data-l10n-id="page_scale_width">Full Width</option>
                                    <option id="customScaleOption" title="" value="custom" disabled="disabled" hidden="true"></option>
                                    <option title="" value="0.5" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 50 }'>50%</option>
                                    <option title="" value="0.75" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 75 }'>75%</option>
                                    <option title="" value="1" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 100 }'>100%</option>
                                    <option title="" value="1.25" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 125 }'>125%</option>
                                    <option title="" value="1.5" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 150 }'>150%</option>
                                    <option title="" value="2" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 200 }'>200%</option>
                                    <option title="" value="3" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 300 }'>300%</option>
                                    <option title="" value="4" data-l10n-id="page_scale_percent" data-l10n-args='{ "scale": 400 }'>400%</option>
                                </select>
                            </span>
                        </div>
                    </div>
                    <div id="loadingBar">
                        <div class="progress">
                            <div class="glimmer">
                            </div>
                        </div>
                    </div>
                </div>
            </div>

            <menu type="context" id="viewerContextMenu">
                <menuitem id="contextFirstPage" label="First Page"
                          data-l10n-id="first_page"></menuitem>
                <menuitem id="contextLastPage" label="Last Page"
                          data-l10n-id="last_page"></menuitem>
                <menuitem id="contextPageRotateCw" label="Rotate Clockwise"
                          data-l10n-id="page_rotate_cw"></menuitem>
                <menuitem id="contextPageRotateCcw" label="Rotate Counter-Clockwise"
                          data-l10n-id="page_rotate_ccw"></menuitem>
            </menu>

            <div id="viewerContainer" tabindex="0">
                <div id="viewer" class="pdfViewer"></div>
            </div>

            <div id="errorWrapper" hidden='true'>
                <div id="errorMessageLeft">
                    <span id="errorMessage"></span>
                    <button id="errorShowMore" data-l10n-id="error_more_info">
                        More Information
                    </button>
                    <button id="errorShowLess" data-l10n-id="error_less_info" hidden='true'>
                        Less Information
                    </button>
                </div>
                <div id="errorMessageRight">
                    <button id="errorClose" data-l10n-id="error_close">
                        Close
                    </button>
                </div>
                <div class="clearBoth"></div>
                <textarea id="errorMoreInfo" hidden='true' readonly="readonly"></textarea>
            </div>
        </div> <!-- mainContainer -->

        <div id="overlayContainer" class="hidden">
            <div id="passwordOverlay" class="container hidden">
                <div class="dialog">
                    <div class="row">
                        <p id="passwordText" data-l10n-id="password_label">Enter the password to open this PDF file:</p>
                    </div>
                    <div class="row">
                        <!-- The type="password" attribute is set via script, to prevent warnings in Firefox for all http:// documents. -->
                        <input id="password" class="toolbarField">
                    </div>
                    <div class="buttonRow">
                        <button id="passwordCancel" class="overlayButton"><span data-l10n-id="password_cancel">Cancel</span></button>
                        <button id="passwordSubmit" class="overlayButton"><span data-l10n-id="password_ok">OK</span></button>
                    </div>
                </div>
            </div>
            <div id="documentPropertiesOverlay" class="container hidden">
                <div class="dialog">
                    <div class="row">
                        <span data-l10n-id="document_properties_file_name">File name:</span> <p id="fileNameField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_file_size">File size:</span> <p id="fileSizeField">-</p>
                    </div>
                    <div class="separator"></div>
                    <div class="row">
                        <span data-l10n-id="document_properties_title">Title:</span> <p id="titleField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_author">Author:</span> <p id="authorField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_subject">Subject:</span> <p id="subjectField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_keywords">Keywords:</span> <p id="keywordsField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_creation_date">Creation Date:</span> <p id="creationDateField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_modification_date">Modification Date:</span> <p id="modificationDateField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_creator">Creator:</span> <p id="creatorField">-</p>
                    </div>
                    <div class="separator"></div>
                    <div class="row">
                        <span data-l10n-id="document_properties_producer">PDF Producer:</span> <p id="producerField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_version">PDF Version:</span> <p id="versionField">-</p>
                    </div>
                    <div class="row">
                        <span data-l10n-id="document_properties_page_count">Page Count:</span> <p id="pageCountField">-</p>
                    </div>
                    <div class="buttonRow">
                        <button id="documentPropertiesClose" class="overlayButton"><span data-l10n-id="document_properties_close">Close</span></button>
                    </div>
                </div>
            </div>
            <div id="printServiceOverlay" class="container hidden">
                <div class="dialog">
                    <div class="row">
                        <span data-l10n-id="print_progress_message">Preparing document for printing…</span>
                    </div>
                    <div class="row">
                        <progress value="0" max="100"></progress>
                        <span data-l10n-id="print_progress_percent" data-l10n-args='{ "progress": 0 }' class="relative-progress">0%</span>
                    </div>
                    <div class="buttonRow">
                        <button id="printCancel" class="overlayButton"><span data-l10n-id="print_progress_close">Cancel</span></button>
                    </div>
                </div>
            </div>
        </div>  <!-- overlayContainer -->

    </div> <!-- outerContainer -->
    <div id="printContainer"></div>
</div>
</body>
</html>

main.js

...
btn.onClick = function() {
  PDFViewerApplication.open('ms-appdata:///local/xxxxx/somefile.pdf'); // It loads a file that was downloaded and stored within the app's local storage
}
...

Answer 1

根据错误消息，您当前正在本地上下文中加载一些远程 Web 内容，出于安全原因，这是不允许的。详情请参考Features and restrictions by context (HTML)的table

因此，要解决此问题，您可以将加载 PDF 部分放入 x-ms-webview:

onDeviceReady 在 index.js:

function onDeviceReady() {
    // Handle the Cordova pause and resume events
    document.addEventListener( 'pause', onPause.bind( this ), false );
    document.addEventListener( 'resume', onResume.bind( this ), false );

    // TODO: Cordova has been loaded. Perform any initialization that requires Cordova here.
        if (cordova.platformId == "windows")
        {
            var webview = document.createElement("x-ms-webview");
            webview.src = "ms-appx-web:///www/pdftest.html";
            webview.width = 500;
            webview.height = 500;
            document.getElementById("main").appendChild(webview);
        }
};

www\pdftest.html:

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
    <canvas id="the-canvas"></canvas>
    <script src="lib/pdf.js"></script>
    <script src="scripts/main.js"></script>
</body>
</html>

www\main.js:

var url = 'http://cdn.mozilla.net/pdfjs/helloworld.pdf';

// 禁用工人以避免另一个跨源问题（工人需要 // 待加载脚本的URL，动态加载一个跨域 // 脚本不起作用）。 // PDFJS.disableWorker = 真；

// 必须指定 workerSrc 属性。 PDFJS.workerSrc = 'http://mozilla.github.io/pdf.js/build/pdf.worker.js';

//异步下载PDF var loadingTask = PDFJS.getDocument(url); loadingTask.promise.then(函数 (pdf) { console.log('PDF loaded');

// Fetch the first page
var pageNumber = 1;
pdf.getPage(pageNumber).then(function (page) {
    console.log('Page loaded');

    var scale = 1.5;
    var viewport = page.getViewport(scale);

    // Prepare canvas using PDF page dimensions
    var canvas = document.getElementById('the-canvas');
    var context = canvas.getContext('2d');
    canvas.height = viewport.height;
    canvas.width = viewport.width;

    // Render PDF page into canvas context
    var renderContext = {
        canvasContext: context,
        viewport: viewport
    };
    var renderTask = page.render(renderContext);
    renderTask.then(function () {
        console.log('Page rendered');
    });
});
}, function (reason) {
    // PDF loading error
    console.error(reason);
});

这里是完整的测试演示：PDFJSCordovaDemo

Windows Cordova 应用程序：应用程序无法在本地上下文中加载远程 Web 内容

Windows Cordova App: An app can’t load remote web content in the local context

viewer

cordova

pdf.js

visual-studio-cordova

uwp