More elegant way to route gclid google parameter in mvc? - asp.net-mvc

For google analytics, and to match the websearch parameters correctly on the keyword strategies, i want to make sure the google supplied gclid parameter gets passed on when redirects happen in the controller.
The reason for the redirect is to do split testing, and A/B testing on landingpages, as well as vanity urls matching the campaign themes better.
Currently - this is the way I "Hack" it:
public class ArtclassController : Controller
{
//
// GET: /Artclass/
public ActionResult Kid(string gclid)
{
string _glcid = gclid;
return RedirectToAction("Index", "ArtClassesForKids", new {glcid= _glcid });
}
My question is - is there a way to do this more elegantly? For instance, in the MVC routing?
(For brevities sake, in the supplied code example I have left out a second redirect, and the random function to choose a different landing page.)

I do not believe that there is a way, though you might be able to get away with using Session or even TempData to accomplish your mission.
Wherever gclid is determined in your code now use:
Session["gclid"] = gclid;
Wherever gclid is needed use:
gclid = Session["gclid"];

Related

Using custom routes instead of /controller/action/{id}

I have to make vanity urls for an already existing site. The requirements are:
The existing controllers are a kind of hierarchical structure and can't go away or be overridden in any way. Examples: domain.com/Dog/vanity and domain.com/Cat/vanity.
Keep existing actions. Any existing actions must take priority so that the page for that action is not stomped on by the vanity url.
take future pages and actions into account so that the above requirement is met (a new vanity url is ignored and the action/view executed instead)
To date, I have tried various solutions with routing that allow me to have domain.com/vanity which is nice but the marketing guys don't like because of the different departments within the company. I've tried routing which will override the existing actions and treats them all as vanities (also not feasible). I've a solution in place that programmatically deals with the url that was requested and redirects to a page that actually exists but this is not scalable in any way.
So far, I know that the vanity portion can be treated as a parameter to the action so that I can fire off the default page in the route (Index) but this is, so far, doesn't preserve the structure.
TL;DR: I need to have a solution that allows for domain/controller/vanity structure while also allowing domain/controller/action
Using AttributeRouting for MVC4 you can accomplish a working solution until you ramp up the replacement project. It'll allow you to keep existing routes while adding new, custom ones with little impact.
[Route("my-vanity/is-cool/post/{id}")]
public ActionResult Index(int id)
{
}
The important part is to remember priority, so you write routes that don't overwrite/are overwritten by existing routes. You can steer this to some degree with properties on the attribute. Below is just an example that will put the added route last in priority for the entire site.
[Route("my-vanity/is-cool", SitePrecedence = -1)]
public ActionResult Index()
{
}
ASP.NET WebApi2 have built in support for attribute routing. With it you can define URL's in whatever way you like (instead of following the /controller/action pattern)
http://www.asp.net/web-api/overview/web-api-routing-and-actions/attribute-routing-in-web-api-2

How to pass data from a View to a Controller

In my View, I have a table pulling various data in. Initially it only shows the rows actionable by that user. However, there is also an option to show all rows. To achieve that so far, I have two hyperlinks above the table, with hrefs of "?isRequiredAction=true" and "?isRequiredAction=false". In the Controller, I have the following:
public ActionResult Index(bool? isRequiredAction){
string userId = User.Identity.Name;
bool ira = true;
if (isRequiredAction != null)
{
ira = Convert.ToBoolean(isRequiredAction);
}
...
return View(model);
So, right now the Controller is getting its parameter from the querystring created by clicking those links. I'm not satisfied with this approach since I don't want to dirty up the URL with this query. Is there a simpler way of achieving what I'm asking? We would like to avoid turning the links into form objects if possible. Thanks.
This MSDN article should help.
From view to controller, you can do a HttpPost or you can pass the data as parameters.
You can create two distinct custom routes, for example:
www.yourapp.com/home
www.yourapp.com/home/showall
After that, you can make both routes target the same action or create a distinct action for each of these routes. Your choice!
Technically, I don't believe there is very appropiriate solution that fits your need because you don't want to make the link form object, nor "dirtying up" the URL. I suggest you to stick with your first approach because there is nothing wrong with dirtying the URL. By "dirtying" your URL, you can make link bookmarkable. If you are really concerned with it, then you can have two choices:
(1) Use Ajax. This way your URL will be unaffected; however, you lose bookmarkability.
(2) Use URL rewriting to make your URL "pretty". This approach, under the hood, equals to "dirtying up" the URL, but in a "pretty" way.

ASP.Net MVC: Check if URL is Authorized

I'd like to simply check from a Controller whether another URL is authorized.
So for example, I'd like to call into a Controller like so:
[HttpPost]
public ActionResult IsUrlAuthorized(string url)
{
bool isAuthorized = // What do I put here?
return Json(isAuthorized);
}
So I'd like to know what I could call to check on whether the current user is authorized for the passed-in URL or not. I'm guessing the answer has something to do with Routes, which sit a little bit outside MVC?
This is a somewhat similar question but not quite the same thing:
ASP.NET MVC. Check if user is authorized from JavaScript
Since the user may or may not be authorized in general, but may not have the right permissions or role assignments to see a specific URL.
Ideas?
Update: I use standard MVC authorization attributes to lock down my app, so I'll just give an example of what that looks like here. In MVC Routes map to Controllers. A single method on a Controller can be restricted to one or more Roles:
public class HomeController : Controller
{
[Authorize(Roles = "User, Moderator")]
public ActionResult ListRecentPosts()
{
. . .
}
}
Or, an entire Controller can be restricted to one or more roles:
[Authorize(Roles = "Admin")]
public class AdminController : Controller
. . .
The actual URL that any of these controller methods responds to is based on a default mapping in a standard MVC app:
routes.MapRoute("Default",
"{controller}/{action}/{id}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
But, you can be nice to your users and make URLs guessable by adding a lot more Routes - as a result, a Controller method can have many names that point to it. You can't just assume and infer the controller name from the URL (even if it maps out that way for half the URLs in the site).
So presumably I either need a way to ask the Routing engine directly whether a URL is authorized for the current user, or a 2-step of asking the Routing engine for which Controller and Method, then ask if those are authorized - hopefully not by using Reflection and matching Roles directly as that again would appear to assume too much.
Update 2: The way this came up is I have an Account strip at the top of my app. Its state can change by selecting one of several accounts you're authorized as. Depending on where you are in the app, the account you chose might have authorization to view this page - and you might be in the middle of filling out a form you don't want to lose. So the naive approach - just refresh when they pick another account - is harmful, and a waste of the user's time even if there is no form and they're just reading a page that's all text.
While that convenience to the user is nice, the user is going to fairly assume that pages they can't see as a user who shouldn't have permission really are denied (and, it would be harmful to leave them on a page that's forbidden - actions taken from it will fail). So I need to know whether to redirect away based on their new permissions.
One of the things I love about .Net is the way many of its best libraries decompose so well, so you can easily recompose things that are part of its normal functionality, or a new twist. Both the Routing module and MVC appear to be very well constructed, so I have to suspect this can be done.
The cheap hack is to ensure that my authorization module returns a consistent redirect status code when a user isn't authorized, and when the user changes their account in the account strip, fire 2 AJAX calls: One to change account, and then a second to the current page over AJAX just to check the HTTP Status Code. 200 OK means leave the page as is, Redirect means follow the redirect. Obviously this is a little ugly, involves an extra HTTP call, creates a false hit in the logs, and makes an assumption about how authorization is handled across the app.
There could be a secondary concern - the page might be authorized, but just change how it works or looks. This particular app has no change in look based on account (besides the account strip itself), and I can handle functionality changes by just providing a custom event that forms listen to - they can reload any relevant data from the server in response to it.
Using UrlAuthorization.CheckUrlAccessForPrincipal only works if you're only using URL authorization. But for MVC using Routing, we highly recommend that you don't use URL authorization to secure an app.
Instead, we recommend using Authorization attributes on the controller class. The reason is there could be multiple URLs that call the same controller action. It's always better to secure the resource at the the resource and not just at the entry ways.
In this particular case, you'd have to get an instance of the controller given the URL. THat's a little tricky as you'll basically have to run the MVC pipeline from the point where you have the URL to the point where you have the controller. It's possible, but seems heavyweight.
I wonder if there isn't a better and simpler way to accomplish your goals. What is it you're really trying to do?
UPDATE: Based on your scenario, it sounds like this is an initial check just for UI purposes. Perhaps all you need to do is make an asynchronous Ajax request to the URL and check the HTTP Status code. If it's a 401 status code, you know the user is not authorized. That seems like the safest bet.
How about UrlAuthorizationModule.CheckUrlAccessForPrincipal method.
UrlAuthorizationModule.CheckUrlAccessForPrincipal Method (System.Web.Security)

ActionResult return to page that called it

I have a ActionLink, that calls my public ActionResult, and I would like it to return back to the page that it was called from, but how?
There are a couple of tricks that you can use for this.
The simplest is ...
return Redirect(HttpContext.Request.UrlReferrer.AbsoluteUri);
AbsoluteUri may not give you the exact path you are looking for, but UrlReferrer should have the imformation you are looking for. Redirect returns a subclass of ActionResult so it is a valid return value.
Another idea is to base the redirect location off of stored values. This is useful when you are going to make multiple requests before you want to redirect, such as when you validate a form and show validation issues on the first response. Another situation will be when the referrer is not a local site. In either case, your referrer won't be what you want it to and you will need to retrieve the correct location from somewhere else.
Specific implementations include using a hidden input field on your form, session state, pulling a descriminator value from your route data, or even just a more constant value like HttpContext.Request.ApplicationPath.
Good luck.
Keep in mind that due to the state-less nature of the web, your ActionResult isn't "called from" your ActionLink as much it is simply a url that the user-agent requested.
Because of this, the only real "built-in" way you can know where that user was coming from is by inspecting the http Request headers to see what the referring page was:
string referrer = Request.Headers["referer"];
You'd then be responsible for parsing out the Action method from this url, if you were going to call it directly. Be aware that this referrer may not be a link within your own site.

ASP.Net MVC - handling bad URL parameters

What's the best way to handle a visitor constructing their own URL and replacing what we expect to be an ID with anything they like?
For example:
ASP.Net MVC - handling bad URL parameters
But the user could just as easily replace the URL with:
https://stackoverflow.com/questions/foo
I've thought of making every Controller Function parameter a String, and using Integer.TryParse() on them - if that passes then I have an ID and can continue, otherwise I can redirect the user to an Unknown / not-found or index View.
Stack Overflow handles it nicely, and I'd like to too - how do you do it, or what would you suggest?
Here's an example of a route like yours, with a constraint on the number:
routes.MapRoute(
"Question",
"questions/{questionID}",
new { controller = "StackOverflow", action = "Question" },
new { questionID = #"\d+" } //Regex constraint specifying that it must be a number.
);
Here we set the questionID to have at least one number. This will also block out any urls containing anything but an integer, and also prevents the need for a nullable int.
Note: This does not take into account numbers that larger than the range of Int32 (-2147483647 - +2147483647). I leave this as an exercise to the user to resolve. :)
If the user enters the url "questions/foo", they will not hit the Question action, and fall through it, because it fails the parameter constraint. You can handle it further down in a catchall/default route if you want:
routes.MapRoute(
"Catchall",
"{*catchall}", // This is a wildcard routes
new { controller = "Home", action = "Lost" }
);
This will send the user to the Lost action in the Home controller. More information on the wildcard can be found here.
NB: The Catchall should reside as the LAST route. Placing it further up the chain will mean that this will handle all others below it, given the lazy nature of routes in ASP.NET MVC.
Here is some useful infromation that might help.
If you have a action method
public ActionResult Edit(int? id)
{}
then if someone types in
/Home/Edit/23
the parameter id will be 23.
however if someone types in
/Home/Edit/Junk
then id will be null which is pretty cool. I thought it would throw a cast error or something. It means that if id is not a null value then it is a valid integer and can be passed to your services etc. for db interaction.
Hope this provides you with some info that I have found whilst testing.
In ASP.NET MVC, you can define a filter implementing IActionFilter interface. You will be able to decorate your action with this attribute so that it will be executed on, before or after your action.
In your case, you will define it to be executed "before" your action. So that, you will be able to cancel it if there is an error in the passed parameters. The key benefit here that you only write the code which checking the passed paramaters once (i.e you define it in your filter) and use it wherever you want in your controller actions.
Read more about MVC filters here: http://haacked.com/archive/2008/08/14/aspnetmvc-filters.aspx
You can specify constraints as regular expressions or define custom constraints. Have a look at this blog post for more information:
http://weblogs.asp.net/stephenwalther/archive/2008/08/06/asp-net-mvc-tip-30-create-custom-route-constraints.aspx
You will still need to deal with the situation where id 43243 doesn't map to anything which could be dealt with as an IActionFilter or in your controller directly.
The problem with that approach is that they still might pass an integer which doesn't map to a page. Just return a 404 if they do that, just as you would with "foo". It's not something to worry about unless you have clear security implications.

Resources