Implement Resolver.cancel()

src/bun.js/api/bun/dns_resolver.zig

@@ -3043,6 +3043,13 @@ pub const DNSResolver = struct {
         return resolver.toJS(globalThis);
     }
 
+    pub fn cancel(this: *DNSResolver, globalThis: *JSC.JSGlobalObject, callframe: *JSC.CallFrame) bun.JSError!JSC.JSValue {
+        _ = callframe;
+        const channel = try this.getChannelOrError(globalThis);
+        c_ares.ares_cancel(channel);
+        return .undefined;
+    }
+
     // Resolves the given address and port into a host name and service using the operating system's underlying getnameinfo implementation.
     // If address is not a valid IP address, a TypeError will be thrown. The port will be coerced to a number.
     // If it is not a legal port, a TypeError will be thrown.

src/bun.js/bindings/BunObject.cpp

@@ -58,6 +58,7 @@ BUN_DECLARE_HOST_FUNCTION(Bun__DNS__lookupService);
 BUN_DECLARE_HOST_FUNCTION(Bun__DNS__prefetch);
 BUN_DECLARE_HOST_FUNCTION(Bun__DNS__getCacheStats);
 BUN_DECLARE_HOST_FUNCTION(Bun__DNSResolver__new);
+BUN_DECLARE_HOST_FUNCTION(Bun__DNSResolver__cancel);
 BUN_DECLARE_HOST_FUNCTION(Bun__fetch);
 BUN_DECLARE_HOST_FUNCTION(Bun__fetchPreconnect);
 BUN_DECLARE_HOST_FUNCTION(Bun__randomUUIDv7);
@@ -378,7 +379,7 @@ static JSValue constructDNSObject(VM& vm, JSObject* bunObject)
         JSC::PropertyAttribute::DontDelete | 0);
     dnsObject->putDirectNativeFunction(vm, globalObject, JSC::Identifier::fromString(vm, "getCacheStats"_s), 0, Bun__DNS__getCacheStats, ImplementationVisibility::Public, NoIntrinsic,
         JSC::PropertyAttribute::DontDelete | 0);
-    dnsObject->putDirectNativeFunction(vm, globalObject, JSC::Identifier::fromString(vm, "newResolver"_s), 0, Bun__DNSResolver__new, ImplementationVisibility::Public, NoIntrinsic,
+    dnsObject->putDirectNativeFunction(vm, globalObject, JSC::Identifier::fromString(vm, "newResolver"_s), 1, Bun__DNSResolver__new, ImplementationVisibility::Public, NoIntrinsic,
         JSC::PropertyAttribute::DontDelete | 0);
     dnsObject->putDirect(vm, JSC::Identifier::fromString(vm, "ADDRCONFIG"_s), jsNumber(AI_ADDRCONFIG),
         JSC::PropertyAttribute::DontDelete | 0);

src/bun.js/node/node.classes.ts

@@ -57,6 +57,10 @@ export default [
         fn: "resolveCname",
         length: 1,
       },
+      cancel: {
+        fn: "cancel",
+        length: 0,
+      },
     },
   }),
   define({

src/js/node/dns.ts

@@ -274,7 +274,9 @@ var InternalResolver = class Resolver {
     this.#resolver = this._handle = dns.newResolver(options);
   }
 
-  cancel() {}
+  cancel() {
+    this.#resolver.cancel();
+  }
 
   static #getResolver(object) {
     return #resolver in object ? object.#resolver : dns;
@@ -751,7 +753,9 @@ const promises = {
       this.#resolver = this._handle = dns.newResolver(options);
     }
 
-    cancel() {}
+    cancel() {
+      this.#resolver.cancel();
+    }
 
     static #getResolver(object) {
       return #resolver in object ? object.#resolver : dns;

test/js/node/test/parallel/test-dns-channel-cancel.js

@@ -0,0 +1,46 @@
+'use strict';
+const common = require('../common');
+const { Resolver } = require('dns');
+const assert = require('assert');
+const dgram = require('dgram');
+
+const server = dgram.createSocket('udp4');
+const resolver = new Resolver();
+
+const desiredQueries = 11;
+let finishedQueries = 0;
+
+server.bind(0, common.mustCall(async () => {
+  resolver.setServers([`127.0.0.1:${server.address().port}`]);
+
+  const callback = common.mustCall((err, res) => {
+    assert.strictEqual(err.code, 'ECANCELLED');
+    assert.strictEqual(err.syscall, 'queryA');
+    assert.strictEqual(err.hostname, `example${finishedQueries}.org`);
+
+    finishedQueries++;
+    if (finishedQueries === desiredQueries) {
+      server.close();
+    }
+  }, desiredQueries);
+
+  const next = (...args) => {
+    callback(...args);
+
+    server.once('message', () => {
+      resolver.cancel();
+    });
+
+    // Multiple queries
+    for (let i = 1; i < desiredQueries; i++) {
+      resolver.resolve4(`example${i}.org`, callback);
+    }
+  };
+
+  server.once('message', () => {
+    resolver.cancel();
+  });
+
+  // Single query
+  resolver.resolve4('example0.org', next);
+}));