[GS] use the request's basePath when processing server-side result urls

[pgayvallet]

Summary

Related to #72331

Fix a bug causing the server-side GS results to use the server's basePath instead of the inbound request's when processing result urls.

Checklist

• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 4696893

Build metrics

distributable file count

id	value	diff	baseline
default	45410	+1	45409

History

• 💚 Build #72564 succeeded ac54fa9

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@elasticmachine merge upstream

[mshustov]

is it possible to reuse basePath.prepend here?

[pgayvallet]

AFAIK there is no way to only retrieve the request-specific (requestScopePath) part of the basePath via the service, as get returns the 'whole' base path:

kibana/src/core/server/http/base_path_service.ts

Lines 43 to 49 in bf04235

	/**
	* returns `basePath` value, specific for an incoming request.
	*/
	public get = (request: KibanaRequest | LegacyRequest) => {
	const requestScopePath = this.basePathCache.get(ensureRawRequest(request)) || '';
	return `${this.serverBasePath}${requestScopePath}`;
	};

and prepend only allow to preprend using the server's base path, not a request-scoped basePath:

kibana/src/core/server/http/base_path_service.ts

Lines 70 to 77 in bf04235

	public prepend = (path: string): string => {
	if (this.serverBasePath === '') return path;
	return modifyUrl(path, (parts) => {
	if (!parts.hostname && parts.pathname && parts.pathname.startsWith('/')) {
	parts.pathname = `${this.serverBasePath}${parts.pathname}`;
	}
	});
	};

But maybe adding a new core API is better. I was surprised to be the first to have such need on the server-side TBH.

I can add something like prependRequestPath(path: string, request: KibanaRequest) to the server-side BasePath?