在 Javascript 中,如何解码包含二进制(例如非 UTF-8)数据的字符串?

In Javascript, how do I decode a string in which decoded string contains binary (e.g. non UTF-8) data?

我有一个表示二进制数据的 base64 字符串(例如,解码后不是一个很好的可读字符串或 UTF-8 数据,否则这个答案会帮助我 -- )。我的 JS 是

var byteCharacters = atob(base64str);

这导致

InvalidCharacterError: Failed to execute 'atob' on 'WorkerGlobalScope': The string to be decoded contains characters outside of the Latin1 range.

如何解码不是 ASCII(甚至 UTF-8 数据)的 base 64 字符串?

编辑: 下面是我所说的字符串类型的示例。使用 Mac,我可以像这样对文件进行 base64 编码

openssl base64 -in ~/Downloads/star.jpg -out ~/Downloads/star.base64

这是生成的 base64 字符串。如果你能用JS工具解码这个,你就解决了问题。通过执行 "cat myfile.base64" 获得以下结果,希望 "cat" 或者我的剪切和粘贴没有在此处引入任何奇怪的字符。

iVBORw0KGgoAAAANSUhEUgAAAQMAAADCCAMAAAB6zFdcAAAAulBMVEUNKlK+vr7/
///FxMMAJU/BwcAAFUgAIU1BUGoAHEsAIE0AI04AHkyztbgAGEkJKFEAEEXU2N48
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您可以试试下面的代码:

function decode_base64(s) {
  var b=l=0, r='',
  m='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
  s.split('').forEach(function (v) {
    b=(b<<6)+m.indexOf(v); l+=6;
    if (l>=8) r+=String.fromCharCode((b>>>(l-=8))&0xff);
  });
  return r;
}  

然后你可以创建一个异步函数来完成你的工作:

function decode_base64_async(s, cb) {
  setTimeout(function () { cb(decode_base64(s)); }, 0);
}  

P.S: 我没有检查过这段代码中的非 ASCII 字符,所以你需要尝试一下

最后编辑这句话来自 2015 年相关

The original solution (deprecated)

当提到 atob、btoa、base64js 和其他库 函数时:使用库节省您的时间并弃用 atob 和 btoa

尝试 base64.js.toByteArray 处理您的数据。按照 link 到图书馆 Github 自述文件:它说它完全按照您的要求行事,好吧,只是往返。

在 Chrome 66.0.3359.181

上使用您的数据 base64js.min.js 成功测试了 @1.3.0

使用您在 Nodejs @4.4.7

中的数据成功测试了 @1.3.0

引自自述文件:

base64js has three exposed functions, byteLength, toByteArray and fromByteArray, which both take a single argument.

  1. byteLength - 采用 base64 字符串和 returns 字节数组长度
  2. toByteArray - 采用 base64 字符串和 returns 字节数组
  3. fromByteArray - 采用字节数组和 returns base64 字符串

如果您可以访问它,我还会针对任何文件 type/structure 测试原始二进制数据 be/have。

你是否用base64测试了base64字符串,首先,它是一个正确的base64字符串吗?

为了公平起见,代码 Example link 和 Github 存储库中的更多信息,当作为脚本包含在客户端中时,请使用:

var byteArray = base64js.toByteArray(myBase64Str)

在 Node 中,你会做:

var fs = require('fs')
var base64js =  require('base64-js')
fs.readFile('pathToMyBase64File', 'utf8', (err, data) => { // here 'utf8' is mandatory
  if (err) throw err;
  var byteArray = base64js.toByteArray(data)
  console.log(base64js.byteLength(data) == byteArray.length)
})

重要,myBase64 文件应使用 utf-8 w/BOM 编码,否则将无法工作。

P.S。 : 我不是contributor这个库,只是一个大家知道的好工具,LICENSE MIT.

正如我在评论中提到的,问题出在编码上。 您共享的 base64 字符串中有很多换行符('\n')。 添加换行符(通过 cat)以提高用户可读性。但是它们在解码时会造成麻烦。 如果您在删除字符串中的所有 '\n' 并尝试使用 atob() 后尝试,它应该可以工作。

获取不带空格或'\n'的base64字符串

在Linux

$ base64 -w 0 ~/Downloads/star.jpg >~/Downloads/star.base64

在Mac中,你可以试试openssl中的-A选项。

$ openssl base64 -A -in ~/Downloads/star.jpg -out ~/Downloads/star.base64

请使用生成的字符串尝试 atob()(直接从文件复制,而不是从 cat 输出复制)。

注意:我不是 Mac 用户