How can I set Cross-Origin in ASP.NET Core?

Question

I have a task about general-token. Each request comes from an IP, and I have to call WithOrigins in each request.

Actually I need an AddScoped service in a middleware.

Please help me

Answer 1

using Microsoft.AspNetCore.Cors.Infrastructure; 
using Microsoft.AspNetCore.Http;

public class CustomCorsPolicyProvider: ICorsPolicyProvider {
    public Task<CorsPolicy> GetPolicyAsync(HttpContext context,string policyName)
{
    // Implement logic to select a policy based on the request
    // For example, you can vary the policy based on the request's origin, headers, etc.

    var corsPolicyBuilder = new CorsPolicyBuilder()
        .WithOrigins("http://example.com") // Replace with dynamic logic
        .AllowAnyMethod()
        .AllowAnyHeader();

    return Task.FromResult(corsPolicyBuilder.Build());
} }

then

public void ConfigureServices(IServiceCollection services) {
    services.AddCors();
    services.AddSingleton<ICorsPolicyProvider, CustomCorsPolicyProvider>();
    // ... other services 
}

AND

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // ... other configurations

    app.UseCors(); // Use the custom CORS policy provider

    // ... other middleware
}