Save base64 string as PDF at client side with Java

2019-01-11 01:14发布

So here my problem: I have a pdf file as a base64 String that i am getting from the server. I would like to use this string to either display the PDF directly to the browser or give it a option of "Save as..." when clicking on a link. Here the code i am using:

<!doctype>
<html>
<head>
   <title>jsPDF</title>
   <script type="text/javascript" src="../libs/base64.js"></script>
   <script type="text/javascript" src="../libs/sprintf.js"></script>
   <script type="text/javascript" src="../jspdf.js"></script>

       <script type="text/javascript">

        function demo1() {
            jsPDF.init();
            jsPDF.addPage();
            jsPDF.text(20, 20, 'Hello world!');
            jsPDF.text(20, 30, 'This is client-side Javascript, pumping out a PDF.');

            // Making Data URI
            var out = jsPDF.output();
            var url = 'data:application/pdf;base64,' + Base64.encode(out);

            document.location.href = url;
         }
    </script>
</head>
<body>

<a href="javascript:demo1()">Run Code</a>

</body>
</html>

Its working fine with Chrome and Safari. Firefox does recognize the pdf but does not display it as FF requires extensions to be present but the data-uri has none in this case. The reason im insisting here, if chrome and safari get it ti work, then there has to be a solution for FF and IE

I know there are a few relevant questions to this but not really the exact one and now also a bit old ones. I know a workaround would be to have the pdf generated at server side but i would like to generate it at client side.

So please intelligent folks, is it possible through some hacks or additional JS download plugins?

3条回答
狗以群分
2楼-- · 2019-01-11 01:23

I know this question is old, but also wanted to accomplish this and came across it while looking. For internet explorer I used code from here to save a Blob. To create a blob from the base64 string there were many results on this site, so its not my code I just can't remember the specific source:

function b64toBlob(b64Data, contentType) {
    contentType = contentType || '';
    var sliceSize = 512;
    b64Data = b64Data.replace(/^[^,]+,/, '');
    b64Data = b64Data.replace(/\s/g, '');
    var byteCharacters = window.atob(b64Data);
    var byteArrays = [];

    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
        var slice = byteCharacters.slice(offset, offset + sliceSize);

        var byteNumbers = new Array(slice.length);
        for (var i = 0; i < slice.length; i++) {
            byteNumbers[i] = slice.charCodeAt(i);
        }

        var byteArray = new Uint8Array(byteNumbers);

        byteArrays.push(byteArray);
    }

    var blob = new Blob(byteArrays, {type: contentType});
    return blob;

Using the linked filesaver:

if (window.saveAs) { window.saveAs(blob, name); }
    else { navigator.saveBlob(blob, name); }
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爷、活的狠高调
3楼-- · 2019-01-11 01:26

You can create an anchor like the one showed below to download the base64 pdf:

<a download=pdfTitle href=pdfData title='Download pdf document' />

where pdfData is your base64 encoded pdf like "data:application/pdf;base64,JVBERi0xLjQKJcOkw7zDtsOfCjIgMCBvYmoKPDwvTGVuZ3RoIDMgMCBSL0ZpbHRlci9GbGF0ZURlY29kZT4+CnN0cmVhbQp4nO1cyY4ktxG911fUWUC3kjsTaBTQ1Ytg32QN4IPgk23JMDQ2LB/0+2YsZAQzmZk1PSPIEB..."

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对你真心纯属浪费
4楼-- · 2019-01-11 01:35

You should be able to download the file using

window.open("data:application/pdf;base64," + Base64.encode(out));
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