HTTPDNS:Best practices for using HTTPDNS with Alibaba Cloud OSS SDK for Node.js

2.1 Install dependencies

First, install the required dependency packages:

Download the Node.js SDK and integration examples: httpdns-nodejs-sdk.zip.

npm install ali-oss

Version requirements:

• ali-oss: >= 4.0.0

• Node.js: >= 12.0.0

• httpdns-nodejs-sdk: >= 1.0.0

2.2 Initialize the HTTPDNS SDK

Initialize the HTTPDNS SDK when the application starts:

const { createClient } = require('httpdns-nodejs-sdk');

// Initialize the HTTPDNS client
const httpdnsClient = createClient({
  accountId: 'your-account-id',
  secretKey: 'your-secret-key', // Optional. Used for authenticated parsing.
});

2.3 Create a custom agent that integrates HTTPDNS

Create a custom HTTPS agent that integrates the HTTPDNS parsing capability:

const https = require('https');
const dns = require('dns');

/**
 * Creates a custom DNS lookup function
 */
function createHTTPDNSLookup(httpdnsClient) {
  return (hostname, options, callback) => {
    // Standardize parameters
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
  
    // Make sure the callback exists
    if (typeof callback !== 'function') {
      throw new Error('callback must be a function');
    }
  
    // Use HTTPDNS to parse the domain name
    const result = this.httpdnsClient.getHttpDnsResultForHostSyncNonBlocking(hostname);
  
    if (result && result.success) {
      const hasIPv4 = result.ipv4 && result.ipv4.length > 0;
      const hasIPv6 = result.ipv6 && result.ipv6.length > 0;
  
      if (hasIPv4 || hasIPv6) {
        if (options && options.all) {
          // Return all IP addresses
          const addresses = [
            ...(hasIPv4 ? result.ipv4.map(ip => ({ address: ip, family: 4 })) : []),
            ...(hasIPv6 ? result.ipv6.map(ip => ({ address: ip, family: 6 })) : [])
          ];
          console.log(`[DNS Lookup] HTTPDNS parsing successful: ${hostname} -> Returning all IP addresses (${addresses.length})`);
          callback(null, addresses);
        } else {
          // Prioritize IPv4, then IPv6
          if (hasIPv4) {
            console.log(`[DNS Lookup] HTTPDNS parsing successful: ${hostname} -> ${result.ipv4[0]} (IPv4)`);
            callback(null, result.ipv4[0], 4);
          } else {
            console.log(`[DNS Lookup] HTTPDNS parsing successful: ${hostname} -> ${result.ipv6[0]} (IPv6)`);
            callback(null, result.ipv6[0], 6);
          }
        }
        return;
      }
    }
  
    console.log(`[DNS Lookup] No available IP from HTTPDNS. Falling back to system DNS for: ${hostname}`);
    dns.lookup(hostname, options, callback);
  };
}

/**
 * Creates an HTTPS agent that integrates HTTPDNS
 */
function createHTTPDNSAgent(httpdnsClient) {
  return new https.Agent({
    lookup: createHTTPDNSLookup(httpdnsClient),
    keepAlive: true,
    maxSockets: 10,
  });
}

2.4 Initialize the OSS client

Initialize the OSS client with the custom agent:

const OSS = require('ali-oss');

/**
 * Creates an OSS client that integrates HTTPDNS
 */
function createOSSClient(httpdnsClient, ossConfig) {
  // Create a custom agent
  const httpsAgent = createHTTPDNSAgent(httpdnsClient);
  
  // Create an OSS client and pass in the custom agent
  const ossClient = new OSS({
    region: ossConfig.region,
    accessKeyId: ossConfig.accessKeyId,
    accessKeySecret: ossConfig.accessKeySecret,
    bucket: ossConfig.bucket,
    httpsAgent: httpsAgent // Core: Pass in the agent that integrates HTTPDNS
  });

  console.log('OSS client created and integrated with HTTPDNS');
  return ossClient;
}

// Example usage
const ossConfig = {
  region: 'oss-cn-hangzhou',
  accessKeyId: 'your-access-key-id',
  accessKeySecret: 'your-access-key-secret',
  bucket: 'your-bucket-name'
};

const ossClient = createOSSClient(httpdnsClient, ossConfig);