如何在Flutter中解码base64 PDF字符串? [英] How to decode base64 PDF string in Flutter?

问题描述

我知道有一个名为dart:convert的程序包，它可以让我解码base64图像.但显然，它不适用于pdf文件.如何在Flutter中解码base64 PDF文件?

I know there is a package called dart:convert which let me decode base64 image. But apparently, it doesn't work with pdf files. How can I decode the base64 PDF file in Flutter?

我想将其存储在Firebase Storage中(我知道该怎么做)，但是我需要File变量来完成它.

I want to store it in Firebase Storage (I know how to do it) but I need the File variable to do it.

我有一个用js节点编写的Web服务，其中有一个POST路由.在那里，我创建了一个pdf文件，并将其编码为base64.响应是一个base64字符串，请查看代码.

I have a web service written in node js where I have a POST route. There, I create a pdf file and encode it to base 64. The response is a base64 string, look at the code.

router.post('/pdf', (req, res, next) => {
    //res.send('PDF');

    const fname = req.body.fname;
    const lname = req.body.lname;

    var documentDefinition = {
        content: [ write your pdf with pdfMake.org ],
        styles: { write your style };

    const pdfDoc = pdfMake.createPdf(documentDefinition);
    pdfDoc.getBase64((data) => {

        res.send({ "base64": data });

    });
});

如您所见，它返回pdf作为base64字符串.

As you can see, it returns the pdf as a base64 string.

现在，在Flutter中，我已经写过:

Now, in Flutter, I have written this:

http.post("https://mypostaddreess.com",body: json.encode({"data1":"data"}))
              .then((response) {
            print("Response status: ${response.statusCode}");
            print("Response body: ${response.body}");

            var data = json.decode(response.body);
            var pdf = base64.decode(data["base64"]);

          });

}

如您所见，我在变量'pdf'中有PDF.但是我不知道如何解码它以下载pdf或在Flutter应用中显示它.

I have the PDF in the variable 'pdf' as you see. But I don't know how to decode it to download the pdf or show it in my Flutter app.

推荐答案

@SwiftingDuster

@SwiftingDuster

添加了一些内容，也许除了解码外，还需要创建一个pdf文件并打开它.

a little added, maybe besides decoding, it's also necessary to create a pdf file and open it.

createPdf() async {
    var bytes = base64Decode(widget.base64String.replaceAll('\n', ''));
    final output = await getTemporaryDirectory();
    final file = File("${output.path}/example.pdf");
    await file.writeAsBytes(bytes.buffer.asUint8List());

    print("${output.path}/example.pdf");
    await OpenFile.open("${output.path}/example.pdf");
    setState(() {});
}

所需的库: 1. open_file 2. path_provider 3. pdf

library needed: 1. open_file 2. path_provider 3. pdf

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