Allow relative URL being used as base URL

[yifanbian-msft]

Based on the specification, the Server URL might be relative; and when consumer tries to customize the server list, this might block Swagger UI from rendering.

Use the following configuration to repro:

    internal class OpenApiConfigurationOptions : DefaultOpenApiConfigurationOptions
    {
        public override OpenApiInfo Info { get; set; } = new OpenApiInfo()
        {
            Title = "Some REST API",
            Version = "1.0.0",
        };

        public override OpenApiVersionType OpenApiVersion { get; set; } = OpenApiVersionType.V3;

        public override bool IncludeRequestingHostName { get; set; } = false;

        public override List<OpenApiServer> Servers { get; set; } = new List<OpenApiServer>()
        {
            new OpenApiServer()
            {
                Url = "/api",
            },
        };
    }

The Uri(string) constructor assumes that the URI string is absolute.

[yifanbian-msft]

@Azure/azure-functions-team @Azure/dotnet-cda to review.

[justinyoo]

@yifanbian-msft Thanks for your PR! I found that there's another line 68 for you to take a look. Would you please find and update the line, please?

[yifanbian-msft]

@justinyoo Actually, for the one on L68, it only gets executed when user didn't specify custom configuration, the this._baseUrl comes from baseUrl, which is an absolute one. It doesn't need UriKind to be specified.

[justinyoo]

I left a comment on your change. Could you take a look?

[justinyoo]

I cloned your repo and run it on my local machine. Unfortunately, this doesn't render the Swagger UI properly. Would you please take a further look?

[yifanbian-msft]

Thanks for catching this! I just took a closer look at the code, maybe we just don't need to parse that URL? I have updated the code, could you take a look?

[justinyoo]

Thanks for the long wait! I found that the issue was actually on the other line. Could you take a look and make an appropriate change on your side?

[justinyoo]

Thanks for clarifying your change. They now make sense to me.