如何从解码缓冲区编码 CBOR答案

【问题标题】：How to encode CBOR from the decoding buffer如何从解码缓冲区编码 CBOR
【发布时间】：2021-11-12 22:27:33
【问题描述】：

在解码、编码和解码 CBOR 时，缓冲区返回的结果不同。

const greenpassData = cbor.decodeAllSync(cbor_data);

// --------------------------------
//Want the CBOR data after decoding  CBOR Data

const greenpassDataEncode = cbor.encode(greenpassData);

console.log(greenpassDataEncode);
console.log(cbor_data);

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/**
 * Simple green pass decoder inspired by https://git.gir.st/greenpass.git/blob_plain/master:/greenpass.py
 *
 * 2021 Lorenzo Millucci
 * 
 * Before usage install following dependecies `npm install base45 cbor jpeg-js jsqr pako`
 */

const base45 = require('base45');
const cbor = require('cbor');
const fs = require('fs');
const jpeg = require('jpeg-js');
const jsQR = require("jsqr");
const pako = require('pako');

// Set the path to the green pass QR
const FILE_PATH = __dirname + '/greenpass.jpeg';

// Read image file
const greenpassJpeg = fs.readFileSync(FILE_PATH);
const greenpassImageData = jpeg.decode(greenpassJpeg, { useTArray: true });

// Decode QR
const decodedGreenpass = jsQR(greenpassImageData.data, greenpassImageData.width, greenpassImageData.height);

// Remove `HC1:` from the string
const greenpassBody = decodedGreenpass.data.substr(4);
console.log(greenpassBody)

// Data is Base45 encoded
const decodedData = base45.decode(greenpassBody);

// And zipped
const output = pako.inflate(decodedData);
const results = cbor.decodeAllSync(output);
[headers1, headers2, cbor_data, signature] = results[0].value;

const greenpassData = cbor.decodeAllSync(cbor_data);

// --------------------------------
//Want the cbor data after decoding  cbor Data

const greenpassDataEncode = cbor.encode(greenpassData);

console.log(greenpassDataEncode);
console.log(cbor_data);
// --------------------------------

var josnString = JSON.stringify(greenpassData[0].get(-260).get(1), null, 2);
//new Encoded Array
const ecodeArrayGreenPassData = cbor.encode(greenpassData);
const greenpassData2 = cbor.decodeAllSync(ecodeArrayGreenPassData);

【问题讨论】：

我也想知道这个。缓冲区中有一些奇怪的第一项，切片时，缓冲区相同 console.log('c', cbor_data); console.log('g', greenpassDataEncode.slice(1));

标签： node.js encoding buffer decoding cbor

【解决方案1】：

也许是因为……

错误..

让您的控制台记录 Pako 创建的内容，这应该类似于：

 Uint8Array(350) [
  210, 132,  67, 
   ....
   35,  68,  98,  99,
  ... 250 more items
]

..而普通的 cbor.encode() 从 decodeAllSync 结果构建，如下所示：

<Buffer 11 21 31 41 51 61 ... 302 more bytes>

..你错过了这一点：

const build = new Uint8Array(cbor.encode(my-decode-result))

玩得开心！

（..但老实说：也花了我一点时间..不过，剩下的路应该更容易。）

【讨论】：

哦.. 刚刚认识到：我不使用“cbor.decodeAllSync()”（返回一个数组），而是使用“cbor.decode()”（..returns 对象）。 ..就像一个魅力。