feat: httpclient_next proxy (#5763)

lazy initialize httpclient_next, since plugins may have accessed
app.httpclient ealier than config.httpclient.lookup modification

Author: Dipper30

lib/egg.js

@@ -297,18 +297,62 @@ class EggApplication extends EggCore {
    */
   createHttpClient(options = {}) {
     let httpClient;
-    options.lookup = options.lookup ?? this.config.httpclient.lookup;
-
     if (this.config.httpclient.useHttpClientNext || this.config.httpclient.allowH2) {
-      httpClient = new this.HttpClientNext(this, options);
+      httpClient = this._createHttpClientNextProxy(options);
     } else if (this.config.httpclient?.enableDNSCache) {
       httpClient = new DNSCacheHttpClient(this, options);
     } else {
+      options.lookup = options.lookup ?? this.config.httpclient.lookup;
       httpClient = new this.HttpClient(this, options);
     }
     return httpClient;
   }
 
+  _createHttpClientNextProxy(options = {}) {
+    const self = this;
+    let realClient = null;
+    const init = () => {
+      if (realClient) return;
+      options.lookup = options.lookup ?? self.config.httpclient.lookup;
+      realClient = new self.HttpClientNext(self, options);
+    };
+    return new Proxy({}, {
+      get(_target, prop) {
+        init();
+        const value = realClient[prop];
+        if (typeof value === 'function') {
+          return value.bind(realClient);
+        }
+        return value;
+      },
+      set(_target, prop, value) {
+        init();
+        realClient[prop] = value;
+        return true;
+      },
+      has(_target, prop) {
+        init();
+        return prop in realClient;
+      },
+      ownKeys() {
+        init();
+        return Reflect.ownKeys(realClient);
+      },
+      getOwnPropertyDescriptor(_target, prop) {
+        init();
+        return Object.getOwnPropertyDescriptor(realClient, prop);
+      },
+      deleteProperty(_target, prop) {
+        init();
+        return delete realClient[prop];
+      },
+      getPrototypeOf() {
+        init();
+        return Object.getPrototypeOf(realClient);
+      },
+    });
+  }
+
   /**
    * HttpClient instance
    * @see https://github.com/node-modules/urllib

test/lib/core/dns_resolver.test.js

@@ -1,4 +1,7 @@
 const utils = require('../../utils');
+const mm = require('egg-mock');
+const dns = require('dns');
+const dnsPromise = require('dns').promises;
 const assert = require('assert');
 
 describe('test/lib/core/dns_resolver.test.js', () => {
@@ -22,6 +25,8 @@ describe('test/lib/core/dns_resolver.test.js', () => {
     url2 = url2.replace('127.0.0.2', 'localhost');
   });
 
+  afterEach(mm.restore);
+
   after(() => {
     if (server1?.server?.listening) server1.server.close();
     if (server2?.server?.listening) server2.server.close();
@@ -76,4 +81,114 @@ describe('test/lib/core/dns_resolver.test.js', () => {
       assert(err.message.includes('fetch failed'));
     }
   });
+
+  it('should not fail even if dns.lookup fail, because lookup is overridden', async () => {
+    mm.error(dnsPromise, 'lookup', 'mock dns lookup error');
+    const res = await app.curl(url2 + '/get_headers', { dataType: 'json' });
+    assert(res.status === 200);
+  });
+});
+
+describe('test/lib/core/dns_resolver with dns error', () => {
+  let server;
+  let app;
+  let url;
+  let originalDNSServers;
+
+  const cache = new Map();
+  before(async () => {
+    server = await utils.startNewLocalServer('127.0.0.1');
+    if (!server) {
+      throw new Error('start local server failed');
+    }
+    app = utils.app('apps/dns_resolver');
+    await app.ready();
+    app.config.httpclient.lookup = function(hostname, options, callback) {
+      if (cache.has(hostname)) {
+        const record = cache.get(hostname);
+        if (options && options.all) {
+          const addresses = record.map(r => ({ address: r.address, family: 4 }));
+          callback(null, addresses);
+          return;
+        }
+        callback(null, record[0].address, 4);
+        return;
+      }
+      dnsPromise.resolve4(hostname, { ttl: true }).then(addresses => {
+        if (addresses && addresses.length !== 0) {
+          if (Array.isArray(addresses)) {
+            cache.set(hostname, addresses);
+          } else {
+            cache.set(hostname, [ addresses ]);
+          }
+          if (options && options.all) {
+            const addrList = addresses.map(r => ({ address: r.address, family: 4 }));
+            callback(null, addrList);
+            return;
+          }
+          callback(null, addresses[0].address, 4);
+        } else {
+          callback(new Error('no addresses found'));
+        }
+      }).catch(err => {
+        callback(err);
+      });
+
+    };
+    url = server.url;
+    url = url.replace('127.0.0.1', 'localhost');
+    originalDNSServers = dns.getServers();
+    dns.setServers([ '223.5.5.5', '223.6.6.6' ]);
+  });
+
+  afterEach(mm.restore);
+
+  after(() => {
+    dns.setServers(originalDNSServers);
+    if (server?.server?.listening) server.server.close();
+  });
+
+
+  it('should cache work when dns fails', async () => {
+    const res1 = await app.curl(url + '/get_headers', { dataType: 'json' });
+    assert(res1.status === 200);
+    assert(cache.has('localhost'));
+
+    mm.error(dnsPromise, 'resolve4', 'mock dns lookup error');
+    const res2 = await app.curl(url + '/get_headers', { dataType: 'json' });
+    assert(res2.status === 200);
+    cache.delete('localhost');
+    // should fail now
+    // assert.error(app.curl(url + '/get_headers', { dataType: 'json' }))
+    let shouldFail = false;
+    try {
+      await app.curl(url + '/get_headers', { dataType: 'json' });
+    } catch (err) {
+      shouldFail = true;
+      assert(err.message.includes('mock dns lookup error'));
+    }
+    assert(shouldFail);
+  });
+
+  it('should cache work when name server fails', async () => {
+    const successRes = await app.curl(url + '/get_headers', { dataType: 'json' });
+    assert(successRes.status === 200);
+    assert(cache.has('localhost'));
+    // can't resolve localhost now, but cache still works
+    dns.setServers([ '8.8.8.8' ]);
+    const res = await app.curl(url + '/get_headers', { dataType: 'json' });
+    assert(res.status === 200);
+
+    // clear cache, should fail now
+    cache.delete('localhost');
+    let shouldFail = false;
+    try {
+      await app.curl(url + '/get_headers', { dataType: 'json' });
+    } catch (err) {
+      shouldFail = true;
+      assert(err.message.includes('queryA ENOTFOUND localhost'));
+    }
+    assert(shouldFail);
+  });
 });
+

test/lib/core/httpclient.test.js

@@ -382,6 +382,53 @@ describe('test/lib/core/httpclient.test.js', () => {
           assert(err.message.includes('url should start with http, but got unknown url'));
         });
     });
+
+    it('should Proxy be fully functional', () => {
+      const httpclient = app.httpclient;
+
+      // Test get trap - method access
+      assert(typeof httpclient.request === 'function');
+      assert(typeof httpclient.curl === 'function');
+      assert(typeof httpclient.safeCurl === 'function');
+
+      // Test has trap - 'in' operator
+      assert('request' in httpclient);
+      assert('curl' in httpclient);
+      assert('safeCurl' in httpclient);
+
+      const ownKeys = Reflect.ownKeys(httpclient);
+      assert(ownKeys.length > 0);
+
+      httpclient.testProp = 'test';
+      const customDescriptor = Object.getOwnPropertyDescriptor(httpclient, 'testProp');
+      assert(customDescriptor);
+      assert.equal(customDescriptor.value, 'test');
+      assert.equal(customDescriptor.writable, true);
+      assert.equal(customDescriptor.enumerable, true);
+      assert.equal(customDescriptor.configurable, true);
+
+      const proto = Object.getPrototypeOf(httpclient);
+      assert(proto);
+      assert(proto instanceof HttpclientNext);
+      assert(proto.constructor);
+
+      httpclient.customProperty = 'test-value';
+      assert.equal(httpclient.customProperty, 'test-value');
+
+      delete httpclient.customProperty;
+      assert.equal(httpclient.customProperty, undefined);
+
+      delete httpclient.testProp;
+      assert.equal(httpclient.testProp, undefined);
+
+      // Test that methods are properly bound
+      const { request } = httpclient;
+      assert(typeof request === 'function');
+
+      // Test Object.getOwnPropertyNames() which uses ownKeys trap
+      const propNames = Object.getOwnPropertyNames(httpclient);
+      assert(Array.isArray(propNames));
+    });
   });
 
   describe('overwrite httpclient support allowH2=true', () => {