Support changing the OpenAPI document based on the request

[botflux]

Is there an existing issue that is already proposing this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe it

I use NestJs with the swagger module in a multi-tenant environment where each customer is a tenant.
All my API endpoints are prefixed with "/:customer/" using setGlobalPrefix.

I want all the requests made by the swagger UI prefixed with the current customer.
For example, if I go on /customer-1/docs, I want all the requests to start with /customer-1/.

I serve my swagger under /:customer/docs using SwaggerModule.setup('/:customer/docs', app, document,{useGlobalPrefix: false}).

In this setup, if I have a route /:customer/my-route, the swagger UI will target /my-route since the swagger module doesn't know there is a global prefix.

I want to be able to change the servers field of the OpenAPI document to add the /:customer part.

Describe the solution you'd like

To support this behaviour, we could pass a function called patchDocument that takes the request, response and document and return a patched document.

SwaggerModule.setup('/:customer/docs', app, document, {
    useGlobalPrefix: false,
    patchDocument: (req: Request, res: Response, document: OpenAPIObject): OpenAPIObject => {
      // change document.servers based on req.params.customer
      // and return the patched document
    }
  });

Teachability, documentation, adoption, migration strategy

No response

What is the motivation / use case for changing the behavior?

In our multi-tenant environment, we want our customers to be isolated. Automatically patching the OpenAPI document based on the request allow us to not add the :customer path param to each request.

[kamilmysliwiec]

Would you like to create a PR for this issue?

[botflux]

Yes !

[kamilmysliwiec]

Let's track this here #2505