CODEWITHSUNDEEP
asp.net-core.net-coreasp.net-core-webapi
w2olves
w2olves

Reputation: 2329

Enabling CORS in ASP.NET Core 6

I have an ASP.NET Core 6 Web API that has a react front end.

I would like to use named policies to enable cors so I have in my startup

public void ConfigureServices(IServiceCollection services)
{
    services.AddCors(options =>
    {
        options.AddPolicy("MyPolicy",
            builder => builder.WithOrigins("http://localhost:3000/"));
    });
 
    services.AddControllersWithViews();
}
 
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
        app.UseHsts();
    }
 
    app.UseHttpsRedirection();
 
    // Shows UseCors with named policy.
    app.UseCors("MyPolicy");
 
    app.UseStaticFiles();
 
    app.UseRouting();
 
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}");
    });
}

Now I can call it in the controller like this:

[EnableCors("MyPolicy")]
public class ProductsController : ControllerBase

This worked in .NET Core 3.1 but not in .NET 6.

What is the right way of doing this in an ASP.NET Core 6 Web API?

Changing the program CS to acomodate CORS policy still doesnt work

 public static void Main(string[] args)
        {
            var host = CreateHostBuilder(args).Build();
            using var scope = host.Services.CreateScope();
           var context = scope.ServiceProvider.GetRequiredService<StoreContext>();
            var logger = scope.ServiceProvider.GetRequiredService<ILogger<Program>>();
            try
            {
                context.Database.Migrate();
                DbInitializer.Initialize(context);
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "Problem migrating data");
            }

            var builder = WebApplication.CreateBuilder(args);
            var MyAllowSpecificOrigins = "AnotherPolicy";

            builder.Services.AddCors(options =>
            {
                options.AddPolicy(name: MyAllowSpecificOrigins,
                   builder =>
                   {
                       builder.AllowAnyOrigin()
                              .AllowAnyHeader()
                              .AllowAnyMethod();
                   });
            });

           var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
            builder.Services.AddDbContext<StoreContext>(options =>
        {
            options.UseSqlite(connectionString);
        });

            builder.Services.AddControllers();

            var app = builder.Build();

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseCors(MyAllowSpecificOrigins);

            app.UseAuthorization();

            app.MapControllers();

            try
            {
                app.Run();
            }
            catch (Exception)
            {

                throw;
            }
           //host.Run();


        }

This gives me the same error Access to fetch at 'http://localhost:5000/api/Products' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: Redirect is not allowed for a preflight request.

Upvotes: 5

Views: 7899

Answers (3)

MX313
MX313

Reputation: 153

This does the trick for me in program.cs

            // global cors policy
        app.UseCors(x => x
            .AllowAnyMethod()
            .AllowAnyHeader()
            .SetIsOriginAllowed(origin => true) // allow any origin 
            .AllowCredentials());

Upvotes: 0

Nawfel Hamdi
Nawfel Hamdi

Reputation: 321

As noted in the documentation:

The specified URL must not contain a trailing slash (/). If the URL terminates with /, the comparison returns false and no header is returned.

Upvotes: 2

Ahsan Ismail
Ahsan Ismail

Reputation: 91

in program.cs file:

app.UseCors(
  options => options.WithOrigins("*").AllowAnyMethod().AllowAnyHeader()
      );

Upvotes: 7

Related Questions