Create Custom 301 Redirect Page

问题

I am attempting to write a 301 redirect scheme using a custom route (class that derives from RouteBase) similar to Handling legacy url's for any level in MVC. I was peeking into the HttpResponse class at the RedirectPermanent() method using reflector and noticed that the code both sets the status and outputs a simple HTML page.

    this.StatusCode = permanent ? 0x12d : 0x12e;
    this.RedirectLocation = url;
    if (UriUtil.IsSafeScheme(url))
    {
        url = HttpUtility.HtmlAttributeEncode(url);
    }
    else
    {
        url = HttpUtility.HtmlAttributeEncode(HttpUtility.UrlEncode(url));
    }
    this.Write("<html><head><title>Object moved</title></head><body>\r\n");
    this.Write("<h2>Object moved to <a href=\"" + url + "\">here</a>.</h2>\r\n");
    this.Write("</body></html>\r\n");

This is desirable, as in my experience not all browsers are configured to follow 301 redirects (although the search engines do). So it makes sense to also give the user a link to the page in case the browser doesn't go there automatically.

What I would like to do is take this to the next level - I want to output the result of an MVC view (along with its themed layout page) instead of having hard coded ugly generic HTML in the response. Something like:

    private void RedirectPermanent(string destinationUrl, HttpContextBase httpContext)
    {
        var response = httpContext.Response;

        response.Clear();
        response.StatusCode = 301;
        response.RedirectLocation = destinationUrl;

        // Output a Custom View Here
        response.Write(The View)

        response.End();
    }

How can I write the output of a view to the response stream?

Additional Information

In the past, we have had problems with 301 redirects from mydomain.com to www.mydomain.com, and subsequently got lots of reports from users that the SSL certificate was invalid. The search engines did their job, but the users had problems until I switched to a 302 redirect. I was actually unable to reproduce it, but we got a significant number of reports so something had to be done.

I plan to make the view do a meta redirect as well as a javascript redirect to help improve reliability, but for those users who still end up at the 301 page I want them to feel at home. We already have custom 404 and 500 pages, why not a custom themed 301 page as well?

回答1:

It turns out I was just over-thinking the problem and the solution was much simpler than I had envisioned. All I really needed to do was use the routeData to push the request to another controller action. What threw me off was the extra 301 status information that needed to be attached to the request.

    private RouteData RedirectPermanent(string destinationUrl, HttpContextBase httpContext)
    {
        var response = httpContext.Response;

        response.CacheControl = "no-cache";
        response.StatusCode = 301;
        response.RedirectLocation = destinationUrl;

        var routeData = new RouteData(this, new MvcRouteHandler());
        routeData.Values["controller"] = "Home";
        routeData.Values["action"] = "Redirect301";
        routeData.Values["url"] = destinationUrl;

        return routeData;
    }

    public override RouteData GetRouteData(HttpContextBase httpContext)
    {
        RouteData result = null;

        // Do stuff here...

        if (this.IsDefaultUICulture(cultureName))
        {
            var urlWithoutCulture = url.ToString().ToLowerInvariant().Replace("/" + cultureName.ToLowerInvariant(), "");

            return this.RedirectPermanent(urlWithoutCulture, httpContext);
        }

        // Get the page info here...

        if (page != null)
        {
            result = new RouteData(this, new MvcRouteHandler());

            result.Values["controller"] = page.ContentType.ToString();
            result.Values["action"] = "Index";
            result.Values["id"] = page.ContentId;
        }

        return result;

    }

I simply needed to return the RouteData so it could be processed by the router!

Note also I added a CacheControl header to prevent IE9 and Firefox from caching the redirect in a way that cannot be cleared.

Now I have a nice page that displays a link and message to the user when the browser is unable to follow the 301, and I will add a meta redirect and javascript redirect to the view to boot - odds are the browser will follow one of them.

Also see this answer for a more comprehensive solution.

回答2:

Assuming you have access to the HttpContextBase here's how you could render the contents of a controller action to the response:

private void RedirectPermanent(string destinationUrl, HttpContextBase httpContext)
{
    var response = httpContext.Response;

    response.Clear();
    response.StatusCode = 301;
    response.RedirectLocation = destinationUrl;

    // Output a Custom View Here (HomeController/SomeAction in this example)
    var routeData = new RouteData();
    routeData.Values["controller"] = "Home";
    routeData.Values["action"] = "SomeAction";
    IController homeController = new HomeController();
    var rc = new RequestContext(new HttpContextWrapper(context), routeData);
    homeController.Execute(rc);

    response.End();
}

This will render SomeAction on HomeController to the response.

来源：https://stackoverflow.com/questions/15234403/create-custom-301-redirect-page

标签

asp.net-mvc

asp.net-mvc-4

asp.net-mvc-routing

url-routing

httpresponse