使用 NodeJS 为 Google Cloud Storage 创建签名 URL

Question

我正在尝试为 Google Cloud Storage 中的私人存储文件创建签名；以便我可以分发一个限时链接。

目前正在这样做，它的签名太短了......我哪里出错了？

var crypto = require("crypto");

var ttl = new Date().getTime() + 3600;
var id = 'the_target_file.txt';
var bucketName = 'bucket_name';
var POLICY_JSON = "GET\n" + "\n" + "\n" + ttl + "\n" + '/' + bucketName + '/' + id;

// stringify and encode the policy
var stringPolicy = JSON.stringify(POLICY_JSON);
var base64Policy = Buffer(stringPolicy, "utf-8").toString("base64");

// sign the base64 encoded policy
var privateKey = "MY_PRIVATE_KEY";
var sha256 = crypto.createHmac("sha256", privateKey);
var signature = sha256.update(new Buffer(base64Policy, "utf-8")).digest("base64");

console.log ( signature );

Answer 1

意识到我做错了什么......我正在对策略字符串进行散列而不是对其进行签名。 下面的代码现在给了我正确的输出。

var crypto = require("crypto");
var fs = require("fs");

var expiry = new Date().getTime() + 3600;
var key = 'the_target_file';
var bucketName = 'bucket_name';
var accessId = 'my_access_id';
var stringPolicy = "GET\n" + "\n" + "\n" + expiry + "\n" + '/' + bucketName + '/' + key; 
var privateKey = fs.readFileSync("gcs.pem","utf8");
var signature = encodeURIComponent(crypto.createSign('sha256').update(stringPolicy).sign(privateKey,"base64"));   
var signedUrl = "https://" + bucketName + ".commondatastorage.googleapis.com/" + key +"?GoogleAccessId=" + accessId + "&Expires=" + expiry + "&Signature=" + signature;

console.log(signedUrl);

为了完整性...这里有一个 PHP 版本，它做同样的事情，我用它来检查我的结果

$expiry = time() + 3600;
$key = 'the_target_file';
$bucketName = 'bucket_name';
$accessId = 'my_access_id';
$stringPolicy = "GET\n\n\n".$expiry."\n/".$bucketName."/".$key;
$fp = fopen('gcs.pem', 'r');
$priv_key = fread($fp, 8192);
fclose($fp);
$pkeyid = openssl_get_privatekey($priv_key,"password"); 
if (openssl_sign( $stringPolicy, $signature, $pkeyid, 'sha256' )) {
    $signature = urlencode( base64_encode( $signature ) );    
    echo 'https://'.$bucketName.'.commondatastorage.googleapis.com/'.
              $key.'?GoogleAccessId='.$accessId.'&Expires='.$expiry.'&Signature='.$signature;
}

Answer 2

现在有一个用于获取签名 URL 的 API/模块。

模块：https://www.npmjs.com/package/@google-cloud/storage
API 文档：https://googleapis.dev/nodejs/storage/latest/File.html#getSignedUrl

例子

var storage = require('@google-cloud/storage')();
var myBucket = storage.bucket('my-bucket');

var file = myBucket.file('my-file');

//-
// Generate a URL that allows temporary access to download your file.
//-
var request = require('request');

var config = {
  action: 'read',
  expires: '03-17-2025'  // this could also include time (MM-DD-YYYYTHH:MM:SSZ)
};

file.getSignedUrl(config, function(err, url) {
  if (err) {
    console.error(err);
    return;
  }

  // The file is now available to read from this URL.
  request(url, function(err, resp) {
    // resp.statusCode = 200
  });
});

Answer 3

假设这个问题是签署由谷歌存储桶后端支持的 CDN url，这对我有用（上面的代码对我不起作用）。

选择和签名函数调用：

const signUrlOptions = {
  expires: '' + new Date().getTime() + 3600, // one hour
  keyName: '_SIGNING_KEY_NAME_', // URL signing key name (the one one you created in the CDN backend bucket)
  keyBase64: '_SIGNING_KEY_BASE64_', // the URL signing key base64 content (base64-encoded, 128-bit value, ~24 characters)
  baseUrl: '_CDN_BASE_URL_' // your base CDN URL (can be IP http://123.... when dev env or https://cdn_dns_name or https dns name)
}

const signedUrl = signCdnUrl('demo.png', signedUrlOptions);

签名功能：

import { createHmac } from 'crypto';

const BASE64_REPLACE = { '+': '-', '/': '_', '=': '' };

export function signCdnUrl(fileName, opts) {
  // URL to sign
  const urlToSign = `${opts.baseUrl}/${fileName}?Expires=${opts.expires}&KeyName=${opts.keyName}`;

  // Compute signature
  const keyBuffer = Buffer.from(opts.keyBase64, 'base64');
  let signature = createHmac('sha1', keyBuffer).update(urlToSign).digest('base64');
  signature = signature.replace(/[+/=]/g, c => (<any>BASE64_REPLACE)[c]); // might be a better way

  // Add signature to urlToSign and return signedUrl
  return urlToSign + `&Signature=${signature}`;
}

希望这会有所帮助。不知何故，谷歌云文档没有 nodejs 示例，并且 file.getSignedUrl() 增加了混乱，因为它似乎与 CDN URL 签名无关。

注意：

注意：可能希望将 base64 -> 缓冲区工作作为 opts.keyBuffer 转移给调用者

Answer 4

如果 nodejs @google-cloud/storage 库已经是您项目的一部分，那么最好的方法是使用它。下面的代码来自 google storage sdk docs for nodejs Link here

npm install @google-cloud/storage

function main(bucketName = 'you_bucket_name', filename = 'your_file_path_without_bucket_name') {
    const {Storage} = require('@google-cloud/storage');

    // Creates a client (Parameters not required if you are already in GCP environment)
    const storage = new Storage({
        projectId: 'your_project_id',
        keyFilename: './json_key_path_for_some_service_account.json'
    });

    async function generateV4ReadSignedUrl() {
        // These options will allow temporary read access to the file
        const options = {
            version: 'v4',
            action: 'read',
            expires: Date.now() + 15 * 60 * 1000, // 15 minutes
        };

        // Get a v4 signed URL for reading the file
        const [url] = await storage
            .bucket(bucketName)
            .file(filename)
            .getSignedUrl(options);

        console.log('Generated GET signed URL:');
        console.log(url);
        console.log('You can use this URL with any user agent, for example:');
        console.log(`curl '${url}'`);
    }

    generateV4ReadSignedUrl().catch(console.error);
    // [END storage_generate_signed_url_v4]
}
main(...process.argv.slice(2));