refactor(logger-plugin): extract getPort logic and add some tests

src/plugins/default/logger-plugin.ts

@@ -2,6 +2,7 @@ import { URL } from 'url';
 import { Plugin } from '../../types';
 import { getLogger } from '../../logger';
 import type { IncomingMessage } from 'node:http';
+import { getPort } from '../../utils/logger-plugin';
 
 type ExpressRequest = {
   /** Express req.baseUrl */
@@ -43,18 +44,19 @@ export const loggerPlugin: Plugin = (proxyServer, options) => {
     const originalUrl = req.originalUrl ?? `${req.baseUrl || ''}${req.url}`;
 
     // construct targetUrl
-    // const port = proxyRes.req?.socket?.autoSelectFamilyAttemptedAddresses?.[0]?.split(':')?.reverse()[0]; //.at(-1),
-    const port = Object.keys(proxyRes.req?.agent?.sockets || {})?.[0]?.split(':')[1];
+    const port = getPort(proxyRes.req?.agent?.sockets);
 
     const obj = {
       protocol: proxyRes.req.protocol,
       host: proxyRes.req.host,
-      port: port,
       pathname: proxyRes.req.path,
     } as URL;
 
     const target = new URL(`${obj.protocol}//${obj.host}${obj.pathname}`);
-    target.port = obj.port; // optional port
+
+    if (port) {
+      target.port = port;
+    }
     const targetUrl = target.toString();
 
     const exchange = `[HPM] ${req.method} ${originalUrl} -> ${targetUrl} [${proxyRes.statusCode}]`;

src/utils/logger-plugin.ts

@@ -0,0 +1,11 @@
+import type { Agent } from 'node:http';
+
+export type Sockets = Pick<Agent, 'sockets'>;
+
+/**
+ * Get port from target
+ * Using proxyRes.req.agent.sockets to determine the target port
+ */
+export function getPort(sockets?: Sockets): string | undefined {
+  return Object.keys(sockets || {})?.[0]?.split(':')[1];
+}

test/unit/utils/logger-plugin.spec.ts

@@ -0,0 +1,23 @@
+import { getPort, type Sockets } from '../../../src/utils/logger-plugin';
+
+describe('getPort()', () => {
+  it('should return port from proxyRes.req.agent.sockets', () => {
+    const sockets = {
+      'jsonplaceholder.typicode.com:80:': [],
+    } as unknown as Sockets;
+
+    expect(getPort(sockets)).toBe('80');
+  });
+
+  it('should handle missing "sockets" from proxyRes?.req?.agent?.sockets', () => {
+    const sockets = undefined;
+
+    expect(getPort(sockets)).toBe(undefined);
+  });
+
+  it('should handle empty "sockets" from proxyRes?.req?.agent?.sockets', () => {
+    const sockets = {} as unknown as Sockets;
+
+    expect(getPort(sockets)).toBe(undefined);
+  });
+});