fix(proxy): close proxy when server closes (#508)

Author: chimurai

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## next
+
+- fix(proxy): close proxy when server closes ([#508](https://github.com/chimurai/http-proxy-middleware/pull/508))
+- refactor(lodash): remove lodash ([#459](https://github.com/chimurai/http-proxy-middleware/pull/459)) ([#507](https://github.com/chimurai/http-proxy-middleware/pull/507)) ([TrySound](https://github.com/TrySound))
+- fix(ETIMEDOUT): return 504 on ETIMEDOUT ([#480](https://github.com/chimurai/http-proxy-middleware/pull/480)) ([aremishevsky](https://github.com/aremishevsky))
+
 ## [v1.0.6](https://github.com/chimurai/http-proxy-middleware/releases/tag/v1.0.6)
 
 - chore(deps): lodash 4.17.20 ([#475](https://github.com/chimurai/http-proxy-middleware/pull/475))

src/http-proxy-middleware.ts

@@ -1,3 +1,4 @@
+import * as https from 'https';
 import * as express from 'express';
 import * as httpProxy from 'http-proxy';
 import { createConfig } from './config-factory';
@@ -12,6 +13,7 @@ export class HttpProxyMiddleware {
   private logger = getInstance();
   private config;
   private wsInternalSubscribed = false;
+  private serverOnCloseSubscribed = false;
   private proxyOptions: Options;
   private proxy: httpProxy;
   private pathRewriter;
@@ -58,13 +60,31 @@ export class HttpProxyMiddleware {
       next();
     }
 
+    /**
+     * Get the server object to subscribe to server events;
+     * 'upgrade' for websocket and 'close' for graceful shutdown
+     *
+     * NOTE:
+     * req.socket: node >= 13
+     * req.connection: node < 13 (Remove this when node 12/13 support is dropped)
+     */
+    const server: https.Server = ((req.socket ?? req.connection) as any)?.server;
+
+    if (server && !this.serverOnCloseSubscribed) {
+      server.on('close', () => {
+        this.logger.info('[HPM] server close signal received: closing proxy server');
+        this.proxy.close();
+      });
+      this.serverOnCloseSubscribed = true;
+    }
+
     if (this.proxyOptions.ws === true) {
       // use initial request to access the server object to subscribe to http upgrade event
-      this.catchUpgradeRequest((req.connection as any).server);
+      this.catchUpgradeRequest(server);
     }
   };
 
-  private catchUpgradeRequest = (server) => {
+  private catchUpgradeRequest = (server: https.Server) => {
     if (!this.wsInternalSubscribed) {
       server.on('upgrade', this.handleUpgrade);
       // prevent duplicate upgrade handling;

test/e2e/express-router.spec.ts

@@ -4,8 +4,8 @@ import { createProxyMiddleware } from './_utils';
 import { Options } from '../../src/index';
 
 describe('Usage in Express', () => {
-  let app;
-  let server;
+  let app: express.Express;
+  let server: http.Server;
 
   beforeEach(() => {
     app = express();
@@ -46,6 +46,7 @@ describe('Usage in Express', () => {
       server = app.listen(3000);
     });
 
+    // FIXME: flaky e2e test; caused by fixed port:3000
     it('should still return a response when route does not match proxyConfig', (done) => {
       let responseBody;
       http.get('http://localhost:3000/sub/hello', (res) => {

test/e2e/http-proxy-middleware.spec.ts

@@ -382,11 +382,12 @@ describe('E2E http-proxy-middleware', () => {
     });
 
     describe('option.logLevel & option.logProvider', () => {
-      let logMessage;
+      let logMessages: string[];
 
       beforeEach(() => {
-        const customLogger = (message) => {
-          logMessage = message;
+        logMessages = [];
+        const customLogger = (message: string) => {
+          logMessages.push(message);
         };
 
         agent = request(
@@ -406,9 +407,12 @@ describe('E2E http-proxy-middleware', () => {
         await mockTargetServer.get('/api/foo/bar').thenReply(200);
         await agent.get(`/api/foo/bar`).expect(200);
 
-        expect(logMessage).toMatchInlineSnapshot(
-          `"[HPM] Proxy created: /api  -> http://localhost:8000"`
-        );
+        expect(logMessages).toMatchInlineSnapshot(`
+          Array [
+            "[HPM] Proxy created: /api  -> http://localhost:8000",
+            "[HPM] server close signal received: closing proxy server",
+          ]
+        `);
       });
     });
   });