fix(event-handler): run global middleware on all requests for REST API

[svozza]

Summary

Fixes bug where global middleware did not run on every request but only if a specific route had been registered. Route handlers are executed as part of a special middleware that is always appended to the end of the middleware stack, if a route handler was not found we would throw a NotFound error and skip the middleware altogether.

In the process of fixing this issue, I also found a bug where if a handler returned a Response object we did not merge the headers from the middleware that had run before into the res.headers object.

Changes

• Removed the code that threw a not found error if a route handler was not found
• Moved the logic to handle returning a 404 to the handler middleware. Returned a 404 Response object rather than throwing to allow middleware stack to run to completion as throwing stops processing completely.
• Fixed a bug where headers were not merged if handler returned a Response object.
• Added tests for new middleware behaviour but did not add a specific test for CORS middleware as this bug is not CORS specific so test lives in main middelware test suite.

Note: if testing the behaviour in a lambda you need to ensure that your OPTIONS request has the Access-Control-Request-Method header or it will not be treated as a pre-flight request and still return a 404.

Issue number: closes #4506

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
8.5% Duplication on New Code

See analysis details on SonarQube Cloud

[dreamorosi]

Thank you - tested on the same website/setup I mentioned in the issue and it works!