I am currently migrating an application originally built on .NET Framework 4.6.1 to .NET 8. The relevant piece of the application is an API Controller that receives a batch of API requests from the browser, and executes them one-by-one on the server side, bundling the responses into a single response.
In the original .NET Framework code, manually created an HttpControllerContext instance, and called the ApiController.ExecuteAsync() method, which works well to replicate the action pipeline and call the correct API Action with the provided querystring and/or form parameters.
In the migrated version, I can’t figure out how to do that. As an initial alternative, I am using reflection to grab the MethodInfo for the controller action. This works for simple cases, but it is very fragile due to possibility of upper/lower case differences, and also method overloading.
Question: I am looking for solutions to effectively migrate and optimize this functionality for ASP.NET Core (.Net 8) and leverage automatic Route binding instead of manually creating the MethodInfo object.
Below is the relevant section of code, before and after migration.
Original code snippet from .NET Framework 4.6.1 that I’m migrating:
// Original .NET Framework 4.6.1 code
private async Task ExecuteItemAsync(
BatchItem item,
BatchApiInternalResult batchResult)
{
try
{
var apiPrefix = webFxOptions.ApiRoutePrefix; // Get the API route prefix from the options
var hostComponents = Request.Host.ToUriComponent().Split(':'); // Split the host into components (hostname and port)
// Build the URI for the API request
var builder = new UriBuilder
{
Scheme = Request.Scheme,
Host = hostComponents[0],
Path = $"api/{item.Controller}/{item.Action}",
Query = this.GetQueryStringForItem(item) // Get the query string for the item
};
// If the host includes a port, set it in the UriBuilder
if (hostComponents.Length == 2)
{
builder.Port = Convert.ToInt32(hostComponents[1]);
}
var uri = builder.Uri; // Construct the final URI
var reqMsg = new HttpRequestMessage(HttpMethod.Get, uri); // Create a new HTTP GET request message
// Get the controller type based on the item.Controller value
var type = BatchApiHelper.Controllers.FirstOrDefault(o => o.Name.Equals(item.Controller + "Controller", StringComparison.CurrentCultureIgnoreCase)) ?? GetType();
// Get the controller instance from the service provider
var controller = serviceProvider.GetService(type) as ControllerBase;
var controllerType = BatchApiHelper.Controllers.FirstOrDefault(o => o.Name.Equals(item.Controller + "Controller", StringComparison.CurrentCultureIgnoreCase));
var controllerDescriptor = new ControllerDescriptor(Configuration, item.Controller, controllerType); // Create a controller descriptor
// Set up the route and route data for the request
var route = Configuration.Routes.FirstOrDefault(o => o.RouteTemplate == "api/{controller}/{id}"); // Find the route matching the template
var routeData = new HttpRouteData(route, new HttpRouteValueDictionary());
routeData.Values.Add("Controller", item.Controller); // Add controller to route data
routeData.Values.Add("Action", item.Action); // Add action to route data
// Create the controller context
var ctlContext = new HttpControllerContext(Configuration, routeData, reqMsg)
{
Controller = controller,
ControllerDescriptor = controllerDescriptor,
Request = reqMsg,
};
ctlContext.RequestContext.Principal = RequestContext.Principal; // Set the user principal in the context
reqMsg.SetRequestContext(ctlContext.RequestContext); // Set the request context
// Execute the controller action
var httpResponse = await controller.ExecuteAsync(ctlContext, CancellationToken.None);
batchResult.Result = (httpResponse.Content as ObjectContent)?.Value; // Get the result from the response content
batchResult.ReasonPhrase = httpResponse.ReasonPhrase; // Set the reason phrase
batchResult.StatusCode = httpResponse.StatusCode; // Set the status code
var headers = httpResponse.Headers.Select(o => new KeyValuePair<string, object>(o.Key, o.Value.FirstOrDefault())); // Get the response headers
batchResult.Headers = headers.ToList();
batchResult.IsSuccessStatusCode = httpResponse.IsSuccessStatusCode; // Check if the response is successful
}
catch (HttpResponseException e) // Handle HttpResponseException separately
{
// HttpResponseException is specifically thrown to return HTTP-specific error details in the response.
// This allows for capturing detailed HTTP response information such as status code and headers.
if (webFxOptions.SanitizeExceptions)
{
// Sanitize the error message if the option is enabled
batchResult.Error = webFxOptions.DefaultApiExceptionMessage;
batchResult.Result = new { message = batchResult.Error };
}
else
{
batchResult.Error = e.ToString();
batchResult.Result = new { message = e.Message };
}
// Capture detailed HTTP response information
batchResult.ReasonPhrase = e.Response.ReasonPhrase;
batchResult.StatusCode = e.Response.StatusCode;
var headers = e.Response.Headers.Select(o => new KeyValuePair<string, object>(o.Key, o.Value.FirstOrDefault()));
batchResult.Headers = headers.ToList();
batchResult.IsSuccessStatusCode = e.Response.IsSuccessStatusCode;
}
catch (Exception e) // Handle general exceptions
{
// General exceptions cover other unexpected errors that may occur during execution.
if (webFxOptions.SanitizeExceptions)
{
// Sanitize the error message if the option is enabled
batchResult.Error = webFxOptions.DefaultApiExceptionMessage;
batchResult.Result = new { message = batchResult.Error };
}
else
{
batchResult.Error = e.ToString();
batchResult.Result = new { message = e.Message };
}
// For general exceptions, set the reason phrase and status code manually
batchResult.ReasonPhrase = e.GetBaseException().Message;
batchResult.StatusCode = HttpStatusCode.InternalServerError;
}
}
Here is the new, “work-in-progress” migrated code for .Net 8:
// New, migrated code for .Net 8
private async Task ExecuteItemAsync(
BatchItem item,
BatchApiInternalResult batchResult)
{
try
{
var apiPrefix = webFxOptions.ApiRoutePrefix; // Get the API route prefix from the options
var hostComponents = Request.Host.ToUriComponent().Split(':'); // Split the host into components (hostname and port)
// Build the URI for the API request
var builder = new UriBuilder
{
Scheme = Request.Scheme,
Host = hostComponents[0],
Path = $"api/{item.Controller}/{item.Action}",
Query = this.GetQueryStringForItem(item) // Get the query string for the item
};
// If the host includes a port, set it in the UriBuilder
if (hostComponents.Length == 2)
{
builder.Port = Convert.ToInt32(hostComponents[1]);
}
var uri = builder.Uri; // Construct the final URI
var reqMsg = new HttpRequestMessage(HttpMethod.Get, uri); // Create a new HTTP GET request message
// Get the controller type based on the item.Controller value
var controllerType = BatchApiHelper.Controllers.FirstOrDefault(o => o.Name.Equals(item.Controller + "Controller", StringComparison.CurrentCultureIgnoreCase)) ?? GetType();
if (controllerType == null)
{
throw new Exception($"Controller '{item.Controller}Controller' not found.");
}
var methodInfo = controllerType.GetMethod(item.Action);
var actionDescriptor = new ControllerActionDescriptor
{
ControllerName = item.Controller,
ActionName = item.Action,
ControllerTypeInfo = controllerType.GetTypeInfo(),
MethodInfo = methodInfo
};
// Create the controller instance
var controller = ActivatorUtilities.CreateInstance(serviceProvider, controllerType) as ControllerBase;
var defaultHttpContext = new DefaultHttpContext { RequestServices = serviceProvider, User = Request.HttpContext.User };
var actionContext = new ActionContext
{
HttpContext = defaultHttpContext,
RouteData = new RouteData(),
ActionDescriptor = actionDescriptor
};
// Set the route data for the request
actionContext.RouteData.Values["controller"] = item.Controller;
actionContext.RouteData.Values["action"] = item.Action;
// Create the action invoker
var invokerFactory = serviceProvider.GetRequiredService<IActionInvokerFactory>();
var invoker = invokerFactory.CreateInvoker(actionContext);
await invoker.InvokeAsync();
// Get the result executor for ObjectResult
ObjectResult objectResult = null;
// Get the type of ControllerActionInvoker
Type invokerType = invoker.GetType();
// Get the _result field (assuming it's a private field)
FieldInfo resultField = invokerType.GetField("_result", BindingFlags.NonPublic | BindingFlags.Instance);
if (resultField != null)
{
// Get the value of _result for the specific invoker instance
objectResult = resultField.GetValue(invoker) as ObjectResult;
}
var content = objectResult?.Value;
//var objectResult = actionContext.HttpContext.Response. as ObjectResult;
batchResult.Result = objectResult?.Value; // Get the result from the response content
batchResult.ReasonPhrase = actionContext.HttpContext.Response.HttpContext.Features.Get<IHttpResponseFeature>().ReasonPhrase; // Set the reason phrase
batchResult.StatusCode = (HttpStatusCode)actionContext.HttpContext.Response.StatusCode; // Set the status code
var headers = actionContext.HttpContext.Response.Headers.Select(o => new KeyValuePair<string, object>(o.Key, o.Value.FirstOrDefault())); // Get the response headers
batchResult.Headers = headers.ToList();
batchResult.IsSuccessStatusCode = actionContext.HttpContext.Response.StatusCode >= 200 && actionContext.HttpContext.Response.StatusCode < 300; // Check if the response is successful
}
//catch (HttpResponseException e) // Handle HttpResponseException separately
//{
// // HttpResponseException is specifically thrown to return HTTP-specific error details in the response.
// // This allows for capturing detailed HTTP response information such as status code and headers.
// if (webFxOptions.SanitizeExceptions)
// {
// // Sanitize the error message if the option is enabled
// batchResult.Error = webFxOptions.DefaultApiExceptionMessage;
// batchResult.Result = new { message = batchResult.Error };
// }
// else
// {
// batchResult.Error = e.ToString();
// batchResult.Result = new { message = e.Message };
// }
// // Capture detailed HTTP response information
// batchResult.ReasonPhrase = e.Response.ReasonPhrase;
// batchResult.StatusCode = e.Response.StatusCode;
// var headers = e.Response.Headers.Select(o => new KeyValuePair<string, object>(o.Key, o.Value.FirstOrDefault()));
// batchResult.Headers = headers.ToList();
// batchResult.IsSuccessStatusCode = e.Response.IsSuccessStatusCode;
//}
catch (Exception e) // Handle general exceptions
{
// General exceptions cover other unexpected errors that may occur during execution.
if (webFxOptions.SanitizeExceptions)
{
// Sanitize the error message if the option is enabled
batchResult.Error = webFxOptions.DefaultApiExceptionMessage;
batchResult.Result = new { message = batchResult.Error };
}
else
{
batchResult.Error = e.ToString();
batchResult.Result = new { message = e.Message };
}
// For general exceptions, set the reason phrase and status code manually
batchResult.ReasonPhrase = e.GetBaseException().Message;
batchResult.StatusCode = HttpStatusCode.InternalServerError;
}
}
Side note I am aware the new code is currently relying on .Net internal types and names (e.g. _result), but not sure how else to get the result information, other than possibly reading the response stream.