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 的包可以让我解码 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?

我想将它存储在 Firebase 存储中(我知道怎么做)，但我需要 File 变量来做到这一点.

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

我有一个用节点 js 编写的 Web 服务，我有一个 POST 路由.在那里，我创建了一个 pdf 文件并将其编码为 base 64.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，它将 pdf 作为 base64 字符串返回.

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

现在，在 Flutter 中，我写了这个:

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.但我不知道如何解码以下载 pdf 或在我的 Flutter 应用中显示.

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

补充一点，可能除了解码之外，还需要创建一个pdf文件并打开.

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('
', ''));
    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(() {});
}

需要的库:1. open_file2. path_provider3.pdf

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

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