using System.Threading.Tasks;

using Microsoft.AspNetCore.Builder;

using Microsoft.AspNetCore.Http;

using Microsoft.AspNetCore.Hosting;

namespace SAPI.API

{

public class OptionsMiddleware

{

private readonly RequestDelegate _next;

private IHostingEnvironment _environment;

public OptionsMiddleware(RequestDelegate next, IHostingEnvironment environment)

{

_next = next;

_environment = environment;

}

public async Task Invoke(HttpContext context)

{

this.BeginInvoke(context);

if (context.Request.Method != "OPTIONS")

{

await this._next.Invoke(context);

}

}

private async void BeginInvoke(HttpContext context)

{

if (context.Request.Method == "OPTIONS")

{

context.Response.Headers.Add("Access-Control-Allow-Origin", new[] { (string)context.Request.Headers["Origin"] });

context.Response.Headers.Add("Access-Control-Allow-Headers", new[] { "Origin, X-Requested-With, Content-Type, Accept" });

context.Response.Headers.Add("Access-Control-Allow-Methods", new[] { "GET, POST, PUT, DELETE, OPTIONS" });

context.Response.Headers.Add("Access-Control-Allow-Credentials", new[] { "true" });

context.Response.StatusCode = 200;

await context.Response.WriteAsync("OK");

}

}

}

public static class OptionsMiddlewareExtensions

{

public static IApplicationBuilder UseOptions(this IApplicationBuilder builder)

{

return builder.UseMiddleware<OptionsMiddleware>();

}

}

}