Add httpAgent option

index.d.ts

@@ -1,5 +1,7 @@
 // Type definitions for express-openid-connect
 
+import type { Agent as HttpAgent } from 'http';
+import type { Agent as HttpsAgent } from 'https';
 import {
   AuthorizationParameters,
   IdTokenClaims,
@@ -590,6 +592,22 @@ interface ConfigParams {
    */
   httpTimeout?: number;
 
+  /**
+   * Specify an Agent or Agents to pass to the underlying http client https://github.com/sindresorhus/got/
+   *
+   * An object representing `http`, `https` and `http2` keys for [`http.Agent`](https://nodejs.org/api/http.html#http_class_http_agent),
+   * [`https.Agent`](https://nodejs.org/api/https.html#https_class_https_agent) and [`http2wrapper.Agent`](https://github.com/szmarczak/http2-wrapper#new-http2agentoptions) instance.
+   *
+   * See https://github.com/sindresorhus/got/blob/v11.8.6/readme.md#agent
+   *
+   * For a proxy agent see https://www.npmjs.com/package/proxy-agent
+   */
+  httpAgent?: {
+    http?: HttpAgent | false;
+    https?: HttpsAgent | false;
+    http2?: unknown | false;
+  };
+
   /**
    * Optional User-Agent header value for oidc client requests.  Default is `express-openid-connect/{version}`.
    */

lib/client.js

@@ -31,6 +31,7 @@ async function get(config) {
         : undefined),
     };
     options.timeout = config.httpTimeout;
+    options.agent = config.httpAgent;
     return options;
   };
 

lib/config.js

@@ -261,6 +261,7 @@ const paramsSchema = Joi.object({
     .default(10 * 60 * 1000),
   httpTimeout: Joi.number().optional().min(500).default(5000),
   httpUserAgent: Joi.string().optional(),
+  httpAgent: Joi.object().optional(),
 });
 
 module.exports.get = function (config = {}) {

test/client.tests.js

@@ -1,3 +1,5 @@
+const { Agent } = require('https');
+const { custom } = require('openid-client');
 const fs = require('fs');
 const { assert, expect } = require('chai').use(require('chai-as-promised'));
 const { get: getConfig } = require('../lib/config');
@@ -270,6 +272,26 @@ describe('client initialization', function () {
     });
   });
 
+  describe('client respects httpAgent configuration', function () {
+    const agent = new Agent();
+
+    const config = getConfig({
+      secret: '__test_session_secret__',
+      clientID: '__test_client_id__',
+      clientSecret: '__test_client_secret__',
+      issuerBaseURL: 'https://op.example.com',
+      baseURL: 'https://example.org',
+      httpAgent: { https: agent },
+    });
+
+    it('should pass agent argument', async function () {
+      const handler = sinon.stub().returns([200]);
+      nock('https://op.example.com').get('/foo').reply(handler);
+      const client = await getClient({ ...config });
+      expect(client[custom.http_options]({}).agent.https).to.eq(agent);
+    });
+  });
+
   describe('client respects clientAssertionSigningAlg configuration', function () {
     const config = {
       secret: '__test_session_secret__',