Develop Reference

ASP.NET Core Razor Page multiple path routing

I'm building a system using ASP.NET Core 2.0 Razor Pages (not MVC) and I'm having trouble adding multiple routes for pages. For example, all pages should be able to be reached by abc.com/language/segment/shop/mypage or abc.com/language/shop/mypage, where both paths point to the same page. The segment path section is optional, then the pages do stuff with the optional segment info.
The question mark syntax in the CombineTemplates markup doesn't seem to work, it seems to only work in the last section of the path. Browsing to a url without a value in the {segment?} section resulted in 404. For example:
AttributeRouteModel.CombineTemplates("{language}/{segment?}/shop", selector.AttributeRouteModel.Template);
I tried code like this below but it only appends the two paths to each other, and I need to be able to enable them both as valid.
options.Conventions.Add(new DefaultPageRouteModelConvention());
options.Conventions.Add(new SegmentPageRouteModelConvention());
In ASP.NET MVC, I could just add two different routes pointing to the same area/controller/action with two different named MapRouteWithName.
Any ideas how to do this with .NET Razor Page syntax?

This code works:
Add a single convention (not two different conventions):
options.Conventions.Add(new CombinedPageRouteModelConvention());
In the new convention, add both route selectors:
private class CombinedPageRouteModelConvention : IPageRouteModelConvention
{
private const string BaseUrlTemplateWithoutSegment = "{language}/shop";
private const string BaseUrlTemplateWithSegment = "{language}/{segment}/shop";
public void Apply(PageRouteModel model)
{
var allSelectors = new List<SelectorModel>();
foreach (var selector in model.Selectors)
{
//setup the route with segment
allSelectors.Add(CreateSelector(selector, BaseUrlTemplateWithSegment));
//setup the route without segment
allSelectors.Add(CreateSelector(selector, BaseUrlTemplateWithoutSegment));
}
//replace the default selectors with new selectors
model.Selectors.Clear();
foreach (var selector in allSelectors)
{
model.Selectors.Add(selector);
}
}
private static SelectorModel CreateSelector(SelectorModel defaultSelector, string template)
{
var fullTemplate = AttributeRouteModel.CombineTemplates(template, defaultSelector.AttributeRouteModel.Template);
var newSelector = new SelectorModel(defaultSelector)
{
AttributeRouteModel =
{
Template = fullTemplate
}
};
return newSelector;
}
}

UrlHelper.Action includes undesired additional parameters

I have a method in the controller ApplicationsController, in which I need to get the base URL for an action method:
public ActionResult MyAction(string id)
{
var url = Url.Action("MyAction", "Applications");
...
}
The problem is that this includes the string id from the current route data, when I need the URL without (the URL is used to fetch content from a CMS on a URL-based lookup).
I have tried passing null and new { } as the routeValues parameter to no avail.
The matching route is as follows (above all other routes):
routes.MapLowercaseRoute(
name: "Applications",
url: "applications/{action}/{id}",
defaults: new { controller = "Applications",
action = "Index", id = UrlParameter.Optional });
I've seen a couple of other questions touch on this but none of them seem to have a viable solution. At present, I am resorting to hardcoding the path in the controller; however, I'd like to be able to abstract this into an action filter, so I need to be able to generate the URL.
Is there a clean/conventional way to prevent this behaviour?

Ok, I see the problem. It's something called "Segment variable reuse". When generating the routes for outbound URLs, and trying to find values for each of the segment variables in a route’s URL pattern, the routing system will look at the values from the current request. This is a behavior that confuses many programmers and can lead to a lengthy debugging session. The routing system is keen to make a match against a route, to the extent that it will reuse segment variable values from the incoming URL. So I think you have to override the value like Julien suggested :
var url = Url.Action("MyAction", "Applications", new { id = "" })

Ended up getting around this with a different approach. The only way I could come up with to prevent arbitrarily-named route values from being inserted into the generated URL was to temporarily remove them from RouteData when calling Url.Action. I've written a couple of extension methods to facilitate this:
public static string NonContextualAction(this UrlHelper helper, string action)
{
return helper.NonContextualAction(action,
helper.RequestContext.RouteData.Values["controller"].ToString());
}
public static string NonContextualAction(this UrlHelper helper, string action,
string controller)
{
var routeValues = helper.RequestContext.RouteData.Values;
var routeValueKeys = routeValues.Keys.Where(o => o != "controller"
&& o != "action").ToList();
// Temporarily remove routevalues
var oldRouteValues = new Dictionary<string, object>();
foreach (var key in routeValueKeys)
{
oldRouteValues[key] = routeValues[key];
routeValues.Remove(key);
}
// Generate URL
string url = helper.Action(routeValues["Action"].ToString(),
routeValues["Controller"].ToString());
// Reinsert routevalues
foreach (var kvp in oldRouteValues)
{
routeValues.Add(kvp.Key, kvp.Value);
}
return url;
}
This allows me to do this in an action filter where I won't necessarily know what the parameter names for the action are (and therefore can't just pass an anonymous object as in the other answers).
Still very much interested to know if someone has a more elegant solution, however.

Use a null or empty value for id to prevent Url.Action from using the current one:
var url = Url.Action("MyAction", "Applications", new { id = "" })

I was not entirely comfortable with the altering, transient or otherwise, of the RouterData in #AntP's otherwise fine solution. Since my code for creating the links was already centralized, I borrowed #Tomasz Jaskuλa and #AntP to augment the ExpandoObject, I was already using.
IDictionary<string,object> p = new ExpandoObject();
// Add the values I want in the route
foreach (var (key, value) in linkAttribute.ParamMap)
{
var v = GetPropertyValue(origin, value);
p.Add(key, v);
}
// Ideas borrowed from https://stackoverflow.com/questions/20349681/urlhelper-action-includes-undesired-additional-parameters
// Null out values that I don't want, but are already in the RouteData
foreach (var key in _urlHelper.ActionContext.RouteData.Values.Keys)
{
if (p.ContainsKey(key))
continue;
p.Add(key, null);
}
var href = _urlHelper.Action("Get", linkAttribute.HRefControllerName, p);

Get site url on mvc

I want to write a little helper function that returns the site url.
Coming from PHP and Codeigniter, I'm very upset that I can't get it to work the way I want.
Here's what I'm trying:
#{
var urlHelper = new UrlHelper(Html.ViewContext.RequestContext);
var baseurl = urlHelper.Content("~");
}
<script>
function base_url(url) {
url = url || "";
return '#baseurl' + url;
}
</script>
I want to return the base url of my application, so I can make ajax calls without worrying about paths. Here's how I intend to use it:
// Development
base_url(); // http://localhost:50024
// Production
base_url("Custom/Path"); // http://site.com/Custom/Path
How can I do something like that?
EDIT
I want absolute paths because I have abstracted js objects that makes my ajax calls.
So suppose I have:
function MyController() {
// ... js code
return $resource('../MyController/:id');
}
// then
var my_ctrl = MyController();
my_ctrl.id = 1;
my_ctrl.get(); // GET: ../MyController/1
This works when my route is http://localhost:8080/MyController/Edit but will fail when is http://localhost:8080/MyController .

I managed to do it like this:
#{
var url = Request.Url;
var baseurl = url.GetLeftPart(UriPartial.Authority);
}
Thank you all!

Are you aware of #Url.Action("actionname") and #Url.RouteUrl("routename") ?
Both of these should do what you're describing.

Instead of manually creating your URL's, you can use #Url.Action() to construct your URLs.
<p>#Url.Action("Index", "Home")</p>
/Home/Index
<p>#Url.Action("Edit", "Person", new { id = 1 })</p>
/Person/Edit/1
<p>#Url.Action("Search", "Book", new { title = "Gone With The Wind" })</p>
/Book/Search?title="Gone+With+The+Wind"
Now the absolute best reason to go with this option is that #Url.Action automatically applies any vanity URL routes you have defined in your Global.asax file. DRY as the sub-saharan desert! :)
In your case, your can create a 'custom path' in two ways.
Option A)
<p>#Url.Action("Path", "Custom")</p>
/Custom/Path
Option B)
You can create a route using the Global.asax file. So your controller/action combo can be anything you want, and you can create a custom vanity route url - regardless of the controller/action combo.

Faceoff: the ASP.NET MVC3 declarative, format stringstyle routing and node's imperitive routing

Here's an example node routing config:
var requestHandlers = require("./requestHandlers");
var handle = {}
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
Its a mapping of URLs and request handlers. Simple, utilitarian, but what about the powerful format string syntax of MVC 3?
routes.MapRoute(
"MediaRoute", // Route name
"{mediaTopic}/{mediaType}/{id}", // URL with parameters
new { controller = "Media", action = "DisplayMediaItemById" },
new { mediaType = "Article|Insight|Infographic" }
It allows for regexes in the {} variable names like mediaType, used in the route and defining its regex.
I'm sure adding regexes to node routing in some way will solve the disconnect. Maybe if someone made the MVC->node transition they will have an answer. Have I missed any great node routing features?

If you just want to turn regexp on your route then look expressjs guide for the answer.

ASP.NET MVC: Redirect from query string params to a canonical url

In my Asp.Net Mvc project I'd like to have a good looking urls, e.g. mysite.com/Page2, and I want to redirect from my old style urls (such as mysite.com?page=2) with 301 state so that there won't be two urls with identical content. Is there a way to do it?
As far as I know Asp.Net binding framework doesn't make difference between query string and curly brace params

I am not sure, I got your question right. It seems, your current setup relies on those GET parameters (like mysite.com?page=2). If you dont want to change this, you will have to use those parameters further. There would be no problem in doing so, though. Your users do not have to use or see them. In order to publish 'new style URLs' only, you may setup a URL redirect in your web server. That would change new style URLs to old style URLs.
The problem is the 301. If the user requests an old style URL, it would be accepted by the webserver as well. Refusing the request with a 301 error seems hard to achieve for me.
In order to get around this, I guess you will have to change your parameter scheme. You site may still rely on GET parameters - but they get a new name. Lets say, your comments are delivered propery for the following (internal) URL in the old scheme:
/Article/1022/Ms-Sharepoint-Setup-Manual?newpage=2
Note the new parameter name. In your root page (or master page, if you are using those), you may handle the redirect permanent (301) manually. Therefore, incoming 'old style requests' are distinguishable by using old parameter names. This could be used to manually assemble the 301 in the response in ASP code.
Personally, I would sugesst, to give up the 301 idea and just use URL redirection.

Well, as far as I can see performing such redirection in ASP.NET MVC might be tricky. This is how I did it:
global.asax:
routes.Add(new QueryStringRoute());
routes.MapRoute(null, "Article/{id}/{name}",
new { controller = "Article", action = "View", page = 1 },
new { page = #"\d+" }
);
routes.MapRoute(null, "Article/{id}/{name}/Page{page}",
new { controller = "Article", action = "View" },
new { page = #"\d+" }
);
QueryStringRoute.cs:
public class QueryStringRoute : RouteBase
{
private static string[] queryStringUrls = new string[]
{
#"~/Article/\d{1,6}/.*?page=\d{1,3}"
};
public override RouteData GetRouteData(HttpContextBase httpContext)
{
string url = httpContext.Request.AppRelativeCurrentExecutionFilePath;
foreach (string queryStringUrl in queryStringUrls)
{
Regex regex = new Regex(queryStringUrl);
if (regex.IsMatch(url))
{
long id = 0; /* Parse the value from regex match */
int page = 0; /* Parse the value from regex match */
string name = ""; /* Parse the value from regex match */
RouteData rd = new RouteData(this, new MvcRouteHandler());
rd.Values.Add("controller", "QueryStringUrl");
rd.Values.Add("action", "Redirect");
rd.Values.Add("id", id);
rd.Values.Add("page", page);
rd.Values.Add("name", name);
rd.Values.Add("controllerToRedirect", "Article");
rd.Values.Add("actionToRedirect", "View");
return rd;
}
}
return null;
}
public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
{
return null;
}
}
QueryStringUrlController.cs:
public class QueryStringUrlController : Controller
{
public RedirectToRouteResult Redirect(long id, int page, string name,
string controllerToRedirect, string actionToRedirect)
{
return RedirectToActionPermanent(actionToRedirect, controllerToRedirect, new { id = id, page = page, name = name });
}
}
Assuming you have such routing as in my global.asax file (listed above) you can create a custom Route class that will handle incoming requests and map them on a special redirection controller which will then redirect them to appropriate urls with 301 state. Then you must add this route to global.asax before your "Article" routes

If you're using IIS 7, the URL Rewrite Module should work for your scenario.