Add punycode support (2.0.6)

2026-05-18 09:35:50 +00:00 · 2019-01-20 03:45:57 -06:00 · 2019-01-20 03:45:57 -06:00 · 05619469b7
commit 05619469b7
parent 5aaff8e1e0
6 changed files with 141 additions and 64 deletions
--- a/lib/DnsResolver.js
+++ b/lib/DnsResolver.js
@ -0,0 +1,71 @@
+const dns = require('dns'),
+    Logger = require('./Logger'),
+    util = require('util'),
+    dnsLookupAsync = util.promisify(dns.lookup),
+    dnsResolveAsync = util.promisify(dns.resolve),
+    punycode = require('punycode');
+
+class DnsResolver {
+    /**
+     * @param {Logger} logger
+     */
+    constructor(logger) {
+        this.logger = logger;
+    }
+
+    isIp(host) {
+        return !!host.match(/\d+\.\d+\.\d+\.\d+/);
+    }
+
+    /**
+     * Response port will only be present if srv record was involved.
+     * @param {string} host
+     * @param {string=} srvRecordPrefix
+     * @returns {Promise<{address:string, port:number=}>}
+     */
+    async resolve(host, srvRecordPrefix) {
+        this.logger.debug("DNS Lookup: " + host);
+
+        if(this.isIp(host)) {
+            this.logger.debug("Raw IP Address: " + host);
+            return {address: host};
+        }
+
+        const asciiForm = punycode.toASCII(host);
+        if (asciiForm !== host) {
+            this.logger.debug("Encoded punycode: " + host + " -> " + asciiForm);
+            host = asciiForm;
+        }
+
+        if (srvRecordPrefix) {
+            this.logger.debug("SRV Resolve: " + srvRecordPrefix + '.' + host);
+            let records;
+            try {
+                records = await dnsResolveAsync(srvRecordPrefix + '.' + host, 'SRV');
+                if (records.length >= 1) {
+                    this.logger.debug("Found SRV Records: ", records);
+                    const record = records[0];
+                    const srvPort = record.port;
+                    const srvHost = record.name;
+                    if (srvHost === host) {
+                        throw new Error('Loop in DNS SRV records');
+                    }
+                    return {
+                        port: srvPort,
+                        ...await this.resolve(srvHost, srvRecordPrefix)
+                    };
+                }
+                this.logger.debug("No SRV Record");
+            } catch (e) {
+                this.logger.debug(e);
+            }
+        }
+
+        this.logger.debug("Standard Resolve: " + host);
+        const {address,family} = await dnsLookupAsync(host);
+        this.logger.debug("Found address: " + address);
+        return {address: address};
+    }
+}
+
+module.exports = DnsResolver;