Getting absolute URLs using ASP NET Core

Question

In MVC 5  I had the following extension methods to generate absolute URLs  instead of relative ones   public static class UrlHelperExtensions       public static string AbsoluteAction          this UrlHelper url          string actionName           string controllerName           object routeValues   null                string scheme   url RequestContext HttpContext Request Url Scheme          return url Action actionName  controllerName  routeValues  scheme              public static string AbsoluteContent          this UrlHelper url          string contentPath                return new Uri url RequestContext HttpContext Request Url  url Content contentPath   ToString               public static string AbsoluteRouteUrl          this UrlHelper url          string routeName          object routeValues   null                string scheme   url RequestContext HttpContext Request Url Scheme          return url RouteUrl routeName  routeValues  scheme             What would the equivalent be in ASP NET Core    UrlHelper RequestContext no longer exists  You can t get hold of the HttpContext as there is no longer a static HttpContext Current property    As far as I can see  you would now require the HttpContext or HttpRequest objects to be passed in also  Am I right  Is there some way to get hold of the current request   Am I even on the right track  should the domain now be an environment variable  which is simple appended to the relative URL  Would this be a better approach

User · Accepted Answer

For ASP NET Core 1 0 Onwards       lt summary gt       lt see cref  IUrlHelper   gt  extension methods       lt  summary gt  public static class UrlHelperExtensions            lt summary gt          Generates a fully qualified URL to an action method by using the specified action name  controller name and         route values           lt  summary gt           lt param name  url  gt The URL helper  lt  param gt           lt param name  actionName  gt The name of the action method  lt  param gt           lt param name  controllerName  gt The name of the controller  lt  param gt           lt param name  routeValues  gt The route values  lt  param gt           lt returns gt The absolute URL  lt  returns gt      public static string AbsoluteAction          this IUrlHelper url          string actionName          string controllerName          object routeValues   null                return url Action actionName  controllerName  routeValues  url ActionContext HttpContext Request Scheme                   lt summary gt          Generates a fully qualified URL to the specified content by using the specified content path  Converts a         virtual  relative  path to an application absolute path           lt  summary gt           lt param name  url  gt The URL helper  lt  param gt           lt param name  contentPath  gt The content path  lt  param gt           lt returns gt The absolute URL  lt  returns gt      public static string AbsoluteContent          this IUrlHelper url          string contentPath                HttpRequest request   url ActionContext HttpContext Request          return new Uri new Uri request Scheme           request Host Value   url Content contentPath   ToString                    lt summary gt          Generates a fully qualified URL to the specified route by using the route name and route values           lt  summary gt           lt param name  url  gt The URL helper  lt  param gt           lt param name  routeName  gt Name of the route  lt  param gt           lt param name  routeValues  gt The route values  lt  param gt           lt returns gt The absolute URL  lt  returns gt      public static string AbsoluteRouteUrl          this IUrlHelper url          string routeName          object routeValues   null                return url RouteUrl routeName  routeValues  url ActionContext HttpContext Request Scheme             Bonus Tip  You can t directly register an IUrlHelper in the DI container  Resolving an instance of IUrlHelper requires you to use the IUrlHelperFactory and IActionContextAccessor  However  you can do the following as a shortcut   services      AddSingleton lt IActionContextAccessor  ActionContextAccessor gt         AddScoped lt IUrlHelper gt  x   gt  x          GetRequiredService lt IUrlHelperFactory gt             GetUrlHelper x GetRequiredService lt IActionContextAccessor gt    ActionContext      ASP NET Core Backlog  UPDATE  This won t make ASP NET Core 5  There are indications that you will be able to use LinkGenerator to create absolute URL s without the need to provide a HttpContext  This was the biggest downside of LinkGenerator and why IUrlHelper although more complex to setup using the solution below was easier to use  See  Make it easy to configure a host scheme for absolute URLs with LinkGenerator

User · Answer

If you just want to convert a relative path with optional parameters I created an extension method for IHttpContextAccessor  public static string AbsoluteUrl this IHttpContextAccessor httpContextAccessor  string relativeUrl  object parameters   null        var request   httpContextAccessor HttpContext Request       var url   new Uri new Uri    request Scheme     request Host Value     relativeUrl  ToString         if  parameters    null                url   Microsoft AspNetCore WebUtilities QueryHelpers AddQueryString url  ToDictionary parameters               return url      private static Dictionary lt string  string gt  ToDictionary object obj        var json   JsonConvert SerializeObject obj       return JsonConvert DeserializeObject lt Dictionary lt string  string gt  gt  json       You can then call the method from your service view using the injected IHttpContextAccessor   var callbackUrl    httpContextAccessor AbsoluteUrl   Identity Account ConfirmEmail   new   userId   applicationUser Id  code

User · Answer

After RC2 and 1 0 you no longer need to inject an IHttpContextAccessor to you extension class  It is immediately available in the IUrlHelper through the urlhelper ActionContext HttpContext Request  You would then create an extension class following the same idea  but simpler since there will be no injection involved   public static string AbsoluteAction      this IUrlHelper url      string actionName       string controllerName       object routeValues   null        string scheme   url ActionContext HttpContext Request Scheme      return url Action actionName  controllerName  routeValues  scheme       Leaving the details on how to build it injecting the accesor in case they are useful to someone  You might also just be interested in the absolute url of the current request  in which case take a look at the end of the answer     You could modify your extension class to use the IHttpContextAccessor interface to get the HttpContext  Once you have the context  then you can get the HttpRequest instance from HttpContext Request and use its properties Scheme  Host  Protocol etc as in   string scheme   HttpContextAccessor HttpContext Request Scheme    For example  you could require your class to be configured with an HttpContextAccessor    public static class UrlHelperExtensions               private static IHttpContextAccessor HttpContextAccessor      public static void Configure IHttpContextAccessor httpContextAccessor                           HttpContextAccessor   httpContextAccessor               public static string AbsoluteAction          this IUrlHelper url          string actionName           string controllerName           object routeValues   null                string scheme   HttpContextAccessor HttpContext Request Scheme          return url Action actionName  controllerName  routeValues  scheme                       Which is something you can do on your Startup class  Startup cs file    public void Configure IApplicationBuilder app                 var httpContextAccessor   app ApplicationServices GetRequiredService lt IHttpContextAccessor gt         UrlHelperExtensions Configure httpContextAccessor                You could probably come up with different ways of getting the IHttpContextAccessor in your extension class  but if you want to keep your methods as extension methods in the end you will need to inject the IHttpContextAccessor into your static class   Otherwise you will need the IHttpContext as an argument on each call     Just getting the absoluteUri of the current request  If you just want to get the absolute uri of the current request  you can use the extension methods GetDisplayUrl or GetEncodedUrl from the UriHelper class   Which is different from the UrLHelper      GetDisplayUrl  Returns the combined components of the request URL in a fully un-escaped form  except for the QueryString  suitable only   for display  This format should not be used in HTTP headers or other   HTTP operations       GetEncodedUrl  Returns the combined components of the request URL in a fully escaped form suitable for use in HTTP headers and other   HTTP operations    In order to use them    Include the namespace Microsoft AspNet Http Extensions   Get the HttpContext instance  It is already available in some classes  like razor views   but in others you might need to inject an IHttpContextAccessor as explained above   Then just use them as in this Context Request GetDisplayUrl     An alternative to those methods would be manually crafting yourself the absolute uri using the values in the HttpContext Request object  Similar to what the RequireHttpsAttribute does    var absoluteUri   string Concat                          request Scheme                                                         request Host ToUriComponent                            request PathBase ToUriComponent                            request Path ToUriComponent                            request QueryString ToUriComponent

User · Answer

You don t need to create an extension method for this  Url Action  quot Action quot    quot Controller quot   values  null    Action - Name of the action Controller - Name of the controller values - Object containing route values  aka GET parameters  There are also lots of other overloads to Url Action you can use to generate links

User · Answer

This is a variation of the anwser by Muhammad Rehan Saeed  with the class getting parasitically attached to the existing  net core MVC class of the same name  so that everything just works   namespace Microsoft AspNetCore Mvc            lt summary gt           lt see cref  IUrlHelper   gt  extension methods           lt  summary gt      public static partial class UrlHelperExtensions                    lt summary gt              Generates a fully qualified URL to an action method by using the specified action name  controller name and             route values               lt  summary gt               lt param name  url  gt The URL helper  lt  param gt               lt param name  actionName  gt The name of the action method  lt  param gt               lt param name  controllerName  gt The name of the controller  lt  param gt               lt param name  routeValues  gt The route values  lt  param gt               lt returns gt The absolute URL  lt  returns gt          public static string AbsoluteAction              this IUrlHelper url              string actionName              string controllerName              object routeValues   null                        return url Action actionName  controllerName  routeValues  url ActionContext HttpContext Request Scheme                           lt summary gt              Generates a fully qualified URL to the specified content by using the specified content path  Converts a             virtual  relative  path to an application absolute path               lt  summary gt               lt param name  url  gt The URL helper  lt  param gt               lt param name  contentPath  gt The content path  lt  param gt               lt returns gt The absolute URL  lt  returns gt          public static string AbsoluteContent              this IUrlHelper url              string contentPath                        HttpRequest request   url ActionContext HttpContext Request              return new Uri new Uri request Scheme           request Host Value   url Content contentPath   ToString                            lt summary gt              Generates a fully qualified URL to the specified route by using the route name and route values               lt  summary gt               lt param name  url  gt The URL helper  lt  param gt               lt param name  routeName  gt Name of the route  lt  param gt               lt param name  routeValues  gt The route values  lt  param gt               lt returns gt The absolute URL  lt  returns gt          public static string AbsoluteRouteUrl              this IUrlHelper url              string routeName              object routeValues   null                        return url RouteUrl routeName  routeValues  url ActionContext HttpContext Request Scheme

User · Answer

I just discovered you can do it with this call   Url Action new UrlActionContext       Protocol   Request Scheme      Host   Request Host Value      Action    Action       This will maintain the scheme  host  port  everything

User · Answer

In a new ASP Net 5 MVC project in a controller action you can still do this Context and this Context Request It looks like on the Request there is no longer a Url property but the child properties  schema  host  etc  are all on the request object directly     public IActionResult About                 ViewBag Message    Your application description page            var schema   this Context Request Scheme           return View            Rather or not you want to use this Context or inject the property is another conversation  Dependency Injection in ASP NET vNext

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If you simply want a Uri for a method that has a route annotation  the following worked for me   Steps  Get Relative URL  Noting the Route name of the target action  get the relative URL using the controller s URL property as follows   var routeUrl   Url RouteUrl   Route Name Here    new    Route parameters here        Create an absolute URL  var absUrl   string Format   0     1  2    Request Scheme              Request Host  routeUrl     Create a new Uri  var uri   new Uri absUrl  UriKind Absolute    Example   Produces  application json     Route  api Children    public class ChildrenController   Controller       private readonly ApplicationDbContext  context       public ChildrenController ApplicationDbContext context                 context   context                GET  api Children      HttpGet      public IEnumerable lt Child gt  GetChild                 return  context Child              HttpGet  uris        public IEnumerable lt Uri gt  GetChildUris                 return from c in  context Child                select                    new Uri                            Request Scheme     Request Host  Url RouteUrl  GetChildRoute   new   id   c ChildId                              UriKind Absolute                  GET  api Children 5      HttpGet   id    Name    GetChildRoute        public IActionResult GetChild  FromRoute  int id                if   ModelState IsValid                        return HttpBadRequest ModelState                      Child child    context Child Single m   gt  m ChildId    id            if  child    null                        return HttpNotFound                       return Ok child

User · Answer

You can get the url like this  Request Headers  quot Referer quot    Explanation The Request UrlReferer will throw a System UriFormatException if the referer HTTP header is malformed  which can happen since it is not usually under your control   As for using Request ServerVariables  per MSDN   Request ServerVariables Collection The ServerVariables collection retrieves the values of predetermined environment variables and request header information   Request Headers Property Gets a collection of HTTP headers  I guess I don t understand why you would prefer the Request ServerVariables over Request Headers  since Request ServerVariables contains all of the environment variables as well as the headers  where Request Headers is a much shorter list that only contains the headers  So the best solution is to use the Request Headers collection to read the value directly  Do heed Microsoft s warnings about HTML encoding the value if you are going to display it on a form  though

[c#] Getting absolute URLs using ASP.NET Core

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