从文件和字符串编码时，Base64 输出不同

Question

我正在尝试根据 this 示例对 S3 策略字符串进行 base64 编码，但是当我使用模板文字将策略字符串分配给变量时，我的代码没有返回预期值。

但是，如果我 copy/paste 完全相同的字符串然后使用 fs 读取文件，它就可以工作。我什至可以对文字字符串进行 base64 编码，获取错误值，解码错误值，将解码后的字符串粘贴到文件中，然后对字符串进行编码（使用 fs）并获得预期结果。

const fs = require('fs')

const policyString =`{ "expiration": "2015-12-30T12:00:00.000Z",
  "conditions": [
    {"bucket": "sigv4examplebucket"},
    ["starts-with", "$key", "user/user1/"],
    {"acl": "public-read"},
    {"success_action_redirect": "http://sigv4examplebucket.s3.amazonaws.com/successful_upload.html"},
    ["starts-with", "$Content-Type", "image/"],
    {"x-amz-meta-uuid": "14365123651274"},
    {"x-amz-server-side-encryption": "AES256"},
    ["starts-with", "$x-amz-meta-tag", ""],

    {"x-amz-credential": "AKIAIOSFODNN7EXAMPLE/20151229/us-east-1/s3/aws4_request"},
    {"x-amz-algorithm": "AWS4-HMAC-SHA256"},
    {"x-amz-date": "20151229T000000Z" }
  ]
}`
const base64FromFile = fs.readFileSync('path/to/policy.txt')
console.log("String1:", base64FromFile.toString('base64'))
const base64FromString = Buffer(policyString).toString('base64')
console.log("String2:", base64FromString)

这是结果。请注意，字符串不同。

String1 (Expected. From file.):

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

String2 (Incorrect. From string variable):
 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

Answer 1

我发现了问题。当我用 crlf 替换所有换行字符时，我得到了正确的 base64 字符串。这很奇怪，因为它似乎直接与文档相矛盾，但它让我得到了正确的结果。

从文件和字符串编码时，Base64 输出不同

Base64 output differs when encoding from file vs string

string

base64

utf-8

fs

node.js