Fix ExpressAdapter to accept Express app directly#504
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These two markdown files are all a human needs to write — the e2e testing skill generates and manages the actual Playwright test code from here. Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
When users passed an http.Server that already had an Express app
(e.g. http.createServer(app)), the adapter created a second Express
app and attached it via server.on('request'), causing double request
handling and ERR_HTTP_HEADERS_SENT errors.
The constructor now accepts http.Server | express.Application:
- Express app: uses it directly, creates server from it (no double handling)
- http.Server: creates internal Express app, attaches to server
- Nothing: creates both (existing behavior)
Fixes #503
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
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Pull request overview
This PR updates the ExpressAdapter to accept an express.Application directly (in addition to an http.Server) to avoid accidentally attaching two Express apps to the same Node server, which can lead to ERR_HTTP_HEADERS_SENT. It also updates the Express http-adapter example and adds tests for the new constructor behavior.
Changes:
- Extend
ExpressAdapterconstructor to accepthttp.Server | express.Application | undefinedand adjust lifecycle handling. - Add tests for passing an Express app into
ExpressAdapterand for start/stop behavior when lifecycle is external. - Update the Express http-adapter example to pass an Express app into the adapter and create the server externally.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| packages/apps/src/http/express-adapter.ts | Adds support for passing an Express app and changes server lifecycle behavior. |
| packages/apps/src/http/express-adapter.spec.ts | Adds coverage for Express-app construction and lifecycle errors. |
| examples/http-adapters/express/teams-app.ts | Updates example to construct adapter with the Express app instead of an http.Server. |
| examples/http-adapters/express/index.ts | Moves server creation/listen into the example’s entrypoint to reflect external lifecycle management. |
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Co-authored-by: Copilot <[email protected]>
corinagum
reviewed
Apr 6, 2026
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Summary
ERR_HTTP_HEADERS_SENTwhen passing anhttp.Serverthat already has an Express app attached — the adapter no longer creates a second Express app in that scenarioExpressAdapterconstructor now acceptshttp.Server | express.Application | undefined:The original
http.Server-only constructor was designed to match theHttpPlugin's capabilities, but it led users into a trap: passinghttp.createServer(app)caused the adapter to attach a second Express app to the same server, resulting in double request handling. Accepting the Express app directly is the natural fix. Ideally, we should probably just not accept an http server and just accept an existing express app. If someone is managing an express app outside, they can continue doing that, and they should be responsible for handling the http server too.Fixes #503
Test plan
express-adaptertests pass (9/9)