How do I get the Controller and Action names from the Referrer Uri?

There's a lot of information for building Uris from Controller and Action names, but how can I do this the other way around?

Basically, all I'm trying to achieve is to get the Controller and Action names from the referring page (i.e. Request.UrlReferrer). Is there an easy way to achieve this?

Solution 1:

I think this should do the trick:

// Split the url to url + query string
var fullUrl = Request.UrlReferrer.ToString();
var questionMarkIndex = fullUrl.IndexOf('?');
string queryString = null;
string url = fullUrl;
if (questionMarkIndex != -1) // There is a QueryString
{    
    url = fullUrl.Substring(0, questionMarkIndex); 
    queryString = fullUrl.Substring(questionMarkIndex + 1);
}   

// Arranges
var request = new HttpRequest(null, url, queryString);
var response = new HttpResponse(new StringWriter());
var httpContext = new HttpContext(request, response)

var routeData = RouteTable.Routes.GetRouteData(new HttpContextWrapper(httpContext));

// Extract the data    
var values = routeData.Values;
var controllerName = values["controller"];
var actionName = values["action"];
var areaName = values["area"];

My Visual Studio is currently down so I could not test it, but it should work as expected.

Solution 2:

To expand on gdoron's answer, the Uri class has methods for grabbing the left and right parts of the URL without having to do string parsing:

url = Request.UrlReferrer.GetLeftPart(UriPartial.Path);
querystring = Request.UrlReferrer.Query.Length > 0 ? uri.Query.Substring(1) : string.Empty;

// Arranges
var request = new HttpRequest(null, url, queryString);
var response = new HttpResponse(new StringWriter());
var httpContext = new HttpContext(request, response)

var routeData = RouteTable.Routes.GetRouteData(new HttpContextWrapper(httpContext));

// Extract the data    
var values = routeData.Values;
var controllerName = values["controller"];
var actionName = values["action"];
var areaName = values["area"];

Solution 3:

To add to gdoran's accepted answer, I found that the action doesn't get populated if a custom route attribute is used. The following works for me:

public static void SetUpReferrerRouteVariables(HttpRequestBase httpRequestBase, ref string previousAreaName, ref string previousControllerName, ref string previousActionName)
{
    // No referrer found, perhaps page accessed directly, just return.
    if (httpRequestBase.UrlReferrer == null) return;

    // Split the url to url + QueryString.
    var fullUrl = httpRequestBase.UrlReferrer.ToString();
    var questionMarkIndex = fullUrl.IndexOf('?');
    string queryString = null;
    var url = fullUrl;
    if (questionMarkIndex != -1) // There is a QueryString
    {
        url = fullUrl.Substring(0, questionMarkIndex);
        queryString = fullUrl.Substring(questionMarkIndex + 1);
    }

    // Arrange.
    var request = new HttpRequest(null, url, queryString);
    var response = new HttpResponse(new StringWriter());
    var httpContext = new HttpContext(request, response);

    var routeData = RouteTable.Routes.GetRouteData(new HttpContextWrapper(httpContext));
    if (routeData == null) throw new AuthenticationRedirectToReferrerDataNotFoundException();

    // Extract the data.
    var previousValues = routeData.Values;
    previousAreaName = previousValues["area"] == null ? string.Empty : previousValues["area"].ToString();
    previousControllerName = previousValues["controller"] == null ? string.Empty : previousValues["controller"].ToString();
    previousActionName = previousValues["action"] == null ? string.Empty : previousValues["action"].ToString();
    if (previousActionName != string.Empty) return;
    var routeDataAsListFromMsDirectRouteMatches = (List<RouteData>)previousValues["MS_DirectRouteMatches"];
    var routeValueDictionaryFromMsDirectRouteMatches = routeDataAsListFromMsDirectRouteMatches.FirstOrDefault();
    if (routeValueDictionaryFromMsDirectRouteMatches == null) return;
    previousActionName = routeValueDictionaryFromMsDirectRouteMatches.Values["action"].ToString();
    if (previousActionName == "") previousActionName = "Index";
}

Solution 4:

Here is a lightweight way to do this without creating response objects.

var values = RouteDataContext.RouteValuesFromUri(Request.UrlReferrer);

var controllerName = values["controller"];
var actionName = values["action"];

Uses this custom HttpContextBase class

public class RouteDataContext : HttpContextBase {
    public override HttpRequestBase Request { get; }

    private RouteDataContext(Uri uri) {
        var url = uri.GetLeftPart(UriPartial.Path);
        var qs = uri.GetComponents(UriComponents.Query,UriFormat.UriEscaped);

        Request = new HttpRequestWrapper(new HttpRequest(null,url,qs));
    }

    public static RouteValueDictionary RouteValuesFromUri(Uri uri) {
        return RouteTable.Routes.GetRouteData(new RouteDataContext(uri)).Values;
    }
}

Solution 5:

The RouteData object can access this info:

 var controller = RouteData.Values["controller"].ToString();
 var action = RouteData.Values["action"].ToString();