Configure cors to allow all subdomains using ASP.NET Core (Asp.net 5, MVC6, VNext)

Question

I have cors setup correctly in an ASP.NET Core web app. Im using the following package...

\"Microsoft.AspNet.Cors\": \"6.0.0-rc1-final\"

an

Answer 1

The out-of-the-box CorsService uses policy.Origins.Contains(origin) to evaluate a request. So, it does not look like there is a trivial way to do what you require, because the List must contain the origin. You could implement your own ICorsService, inherit what the out-of-the-box CorsService already provides, and tweak the methods to handle the *.mydomain.com wildcard.

Edit Here is what I accomplished using yo aspnet to generate a 1.0.0-rc1-update2 Web Api project. It works. Register your service in Startup.cs (see CorsServiceCollectionExtensions for details.)

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddOptions();

        services.TryAdd(
            ServiceDescriptor.Transient());

        services.TryAdd(
            ServiceDescriptor.Transient());
    }

    public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
    {
        loggerFactory.AddConsole(minLevel: LogLevel.Verbose);

        app.UseCors(corsPolictyBuilder =>
        {
            corsPolictyBuilder.WithOrigins("*.mydomain.com");
        });

        app.Run(async context =>
        {
            await context.Response.WriteAsync(
                $"Is Cors? {context.Request.Headers.ContainsKey(CorsConstants.Origin)}");
        });
    }
}

Here is the service, awaiting your implementation. You can either copy/paste or inherit from CorsService.

public class MyCorsService : CorsService, ICorsService
{
    private ILogger _logger;

    public MyCorsService(IOptions options, ILogger logger)
        : base(options)
    {
        _logger = logger;
        _logger.LogInformation("MyCorsService");
    }

    public override void ApplyResult(
        CorsResult result, HttpResponse response)
    {
        _logger.LogInformation("ApplyResult");
        base.ApplyResult(result, response);
    }

    public override void EvaluateRequest(
        HttpContext context, CorsPolicy policy, CorsResult result)
    {
        _logger.LogInformation("EvaluateRequest");
        base.EvaluateRequest(context, policy, result);
    }

    public override void EvaluatePreflightRequest(
        HttpContext context, CorsPolicy policy, CorsResult result)
    {
        _logger.LogInformation("EvaluatePreflightRequest");
        base.EvaluatePreflightRequest(context, policy, result);
    }
}