What is CORS in ASP.NET Core?

What is CORS in ASP.NET Core?

CORS stands for Cross-Origin Resource Sharing. It's a security feature that allows or restricts resources on a web page to be requested from another domain outside the domain from which the first resource was served.

How do I enable CORS in my ASP.NET Core application?

You can enable CORS in ASP.NET Core by adding the CORS services in the ConfigureServices method and then using the CORS middleware in the Configure method of your Startup.cs file.

Can you show me an example of how to configure CORS?

Sure! In your Startup.cs, you can add services like this:

public void ConfigureServices(IServiceCollection services)
{
    services.AddCors(options =>
    {
        options.AddPolicy("AllowAllOrigins",
            builder => builder.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader());
    });
}

And then use it in the Configure method:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseCors("AllowAllOrigins");
    // other middleware
}

What are the security implications of enabling CORS?

Enabling CORS can expose your API to requests from other domains, which can be a security risk if not configured properly. It's important to restrict origins to trusted domains and to only allow the necessary HTTP methods and headers.