fix(devtools-proxy-support): add yet another proxy-agent workaround (#453)

Author: addaleax

packages/devtools-proxy-support/src/agent.spec.ts

@@ -345,4 +345,21 @@ q/I2+0j6dAkOGcK/68z7qQXByeGri3n28a1Kn6o=
       }
     });
   });
+
+  context('invalid arguments', function () {
+    it('does not receive unhandled rejections when using invalid options', async function () {
+      // This test may seem contrived, but it mimics FIPS mode without a valid system FIPS config
+      // (i.e. OpenSSL cannot load ciphers) -- this should result in a handled rejection, rather than
+      // an unhandled one.
+      try {
+        await get(
+          'https://example.com/hello',
+          createAgent({ ciphers: 'unknown' } as any)
+        );
+        expect.fail('missed exception');
+      } catch (err: any) {
+        expect(err.message).to.include('no cipher match');
+      }
+    });
+  });
 });

packages/devtools-proxy-support/src/agent.ts

@@ -1,8 +1,9 @@
 import { ProxyAgent } from './proxy-agent';
-import type { Agent } from 'https';
+import type { Agent as HTTPSAgent } from 'https';
 import type { DevtoolsProxyOptions } from './proxy-options';
 import { proxyForUrl } from './proxy-options';
-import type { ClientRequest, Agent as HTTPAgent } from 'http';
+import type { ClientRequest } from 'http';
+import { Agent as HTTPAgent } from 'http';
 import type { TcpNetConnectOpts } from 'net';
 import type { ConnectionOptions, SecureContextOptions } from 'tls';
 import type { Duplex } from 'stream';
@@ -16,7 +17,7 @@ import { mergeCA, systemCA } from './system-ca';
 // Helper type that represents an https.Agent (= connection factory)
 // with some custom properties that TS does not know about and/or
 // that we add for our own purposes.
-export type AgentWithInitialize = Agent & {
+export type AgentWithInitialize = HTTPSAgent & {
   // This is genuinely custom for our usage (to allow establishing an SSH tunnel
   // first before starting to push connections through it)
   initialize?(): Promise<void>;
@@ -96,7 +97,18 @@ class DevtoolsProxyAgent extends ProxyAgent implements AgentWithInitialize {
     }
     this._req = req;
     this._reqLock = new Promise((resolve) => (this._reqLockResolve = resolve));
-    return await super.connect(req, opts);
+    const agent = await super.connect(req, opts);
+    // Work around https://github.com/TooTallNate/proxy-agents/pull/330
+    if ('addRequest' in agent && typeof agent.addRequest === 'function') {
+      const dummyHttpAgent = Object.assign(new HTTPAgent(), {
+        addRequest() {
+          //ignore
+        },
+      });
+      agent.addRequest(req, opts);
+      return dummyHttpAgent;
+    }
+    return agent;
   }
 
   destroy(): void {