Openapi endpoint must provide CORS

[rafabene]

Environment Details

• Helidon Version: 1.4.4
• Helidon MP
• JDK version: N/A
• OS: N/A
• Docker version (if applicable):

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Problem Description

A Swagger-UI running outside Helidon application can't consume /openapi as it doesn't provide CORS support.
The response at Swagger-UI is Possible cross-origin (CORS) issue? The URL origin (http://localhost:8080) does not match the page (http://localhost). Check the server returns the correct 'Access-Control-Allow-*' headers.

I've implemented a custom CORSFilter/ContainerResponseFilter but it didn't affect /openapi

A property openapi.cors=true configuration should be provided to enable/disable CORS at /openapi endpoint.

Steps to reproduce

1. Execute Swagger-UI with docker run -p 80:8080 swaggerapi/swagger-ui
2. Execute a Helidon-MP application with OpenAPI enabled.
3. Open the URL http://localhost/?url=http://localhost:8080/openapi in any browser

[tjquinno]

This is not an issue in 2.x or later releases and we are not planning to fix this in 1.x.