Introduction
ASP.NET is a popular programming language used for building web applications. One of the common challenges faced by developers is the failure of the ASP.NET Core HttpsRedirectionMiddleware to determine the HTTPS port for a request. In this article, we will explore this issue and provide possible solutions with examples.
Understanding the Problem
The HttpsRedirectionMiddleware in ASP.NET Core is responsible for redirecting HTTP requests to HTTPS. However, in some cases, it fails to determine the HTTPS port for a request, resulting in an error message like “Failed to determine the HTTPS port for redirect.” This can occur when the application is hosted behind a reverse proxy or load balancer.
Solution 1: Configuring Forwarded Headers
To solve this issue, we can configure the ASP.NET Core application to trust the forwarded headers from the reverse proxy or load balancer. This can be done by adding the following code to the ConfigureServices method in the Startup.cs file:
This code configures the application to trust the X-Forwarded-Proto header, which contains the scheme (HTTP or HTTPS) used by the reverse proxy or load balancer.
Solution 2: Setting the HTTPS Port Manually
If the forwarded headers solution doesn't work or is not applicable, we can manually set the HTTPS port in the application code. This can be done by adding the following code to the Configure method in the Startup.cs file:
app.UseHttpsRedirection();
app.Use((context, next) =>
{
context.Request.Scheme = "https";
context.Request.Host = new HostString(context.Request.Host.Host, 443);
return next();
});
This code explicitly sets the scheme to “https” and the port to 443, which is the default HTTPS port. This ensures that the HttpsRedirectionMiddleware correctly determines the HTTPS port for the request.
Conclusion
The failure of the ASP.NET Core HttpsRedirectionMiddleware to determine the HTTPS port for a request can be resolved by either configuring the application to trust forwarded headers or manually setting the HTTPS port in the code. By following the solutions provided in this article, developers can overcome this issue and ensure proper redirection from HTTP to HTTPS in their ASP.NET Core applications.
