How do I resolve a path relative to an ASP.NET MVC 4 application root?

Question

How do I resolve paths relative to an ASP.NET MVC 4 application's root directory? That is, I want to open files belonging to the application from controller actions, referenced like ~/Data/data.html. These paths are typically specified in Web.config.

EDIT:

By 'resolve' I mean to transform a path relative to the application's root directory to an absolute path, .e.g. ~/Data/data.html → C:\App\Data\Data.html.

@Nate What do you mean, that the ~ gets expanded automatically? — aknuds1, Sep 02 '12 at 19:25
[HttpContext.Current.Server.MapPath](http://msdn.microsoft.com/en-us/library/system.web.httpserverutility.mappath.aspx) ? — nemesv, Sep 02 '12 at 19:28
Explain what you mean by "resolve". You want to send a file to the user? You want to reference an image or css file in an element in your page? You want create a link to the file? — Erik Funkenbusch, Sep 02 '12 at 19:32
@aknuds1 - That doesn't help. For what PURPOSE are you trying to do this? — Erik Funkenbusch, Sep 02 '12 at 19:38
@MystereMan The file is only to be read on the server, it doesn't really matter though as I'm only interested in getting the absolute path name... That should be enough to define the scope of the problem. — aknuds1, Sep 02 '12 at 19:38
Ah ok so you want to get the Absolute path to the App_Data folder? — Nate-Wilkins, Sep 02 '12 at 19:39
@Nate Yes, unless there's some more idiomatic/automatic way to expand paths specified in Web.config relative to application root. — aknuds1, Sep 02 '12 at 19:40
Yea you would use MapPath (see answer) that will give you the Absolute path. — Nate-Wilkins, Sep 02 '12 at 19:42

Nate-Wilkins · Accepted Answer · 2013-07-15T16:17:02.703

85

To get the absolute path use this:

String path = HttpContext.Current.Server.MapPath("~/Data/data.html");

EDIT:

To get the Controller's Context remove .Current from the above line. By using HttpContext by itself it's easier to Test because it's based on the Controller's Context therefore more localized.

I realize now that I dislike how Server.MapPath works (internally eventually calls HostingEnvironment.MapPath) So I now recommend to always use HostingEnvironment.MapPath because its static and not dependent on the context unless of course you want that...

edited Jul 15 '13 at 16:17

answered Sep 02 '12 at 19:30

Nate-Wilkins

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I just want to read the file on the server, it's not to be returned to the client. – aknuds1 Sep 02 '12 at 19:37
This is the way to do it. Also, if you need to use this statically, see this question: http://stackoverflow.com/questions/3795986/using-server-mappath-inside-a-static-field-in-asp-net-mvc – Maxim Zaslavsky Sep 02 '12 at 19:42
I'm in a non-static method of a System.Web.Mvc.Controller subclass, but `HttpContext` has no property `Current`. What's up? – aknuds1 Sep 02 '12 at 19:47
Replace `Current` with `ApplicationInstance` – Nate-Wilkins Sep 02 '12 at 19:51
It seems to me I can user `HttpContext` instead of `HttpContext.Current` as it is a `Controller` instance property. See http://stackoverflow.com/questions/785413/difference-between-httpcontext-current-and-controller-context-in-mvc-asp-net. – aknuds1 Sep 02 '12 at 19:54
Yes you can if you want the Context of the Controller and not the application. – Nate-Wilkins Sep 02 '12 at 19:56
From what I understand it's typically preferable to use the `HttpContext` property as it can be mocked when testing, want to update your answer as such? It works at least. – aknuds1 Sep 02 '12 at 19:59

score 64 · Answer 2 · answered Mar 26 '13 at 21:20

64

I find this code useful when I need a path outside of a controller, such as when I'm initializing components in Global.asax.cs:

HostingEnvironment.MapPath("~/Data/data.html")

answered Mar 26 '13 at 21:20

Michael L Perry

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HostingEnvironment.MapPath is a better answer. When you execute the code outside the context of a http request then HttpContext.Current is null and your code crashes. HostingEnvironment.MapPath always works. – JDC Apr 16 '15 at 09:36
1

That is also worth mentioning that "HostingEnvironment.MapPath" can be customized if you have your own implementation of a Virtual Path Provider. Works in any "hosted" environment (windows service or iis hosted) https://support.microsoft.com/en-us/kb/910441 – Rikki Jan 06 '16 at 11:27

score 15 · Answer 3 · answered Jan 28 '13 at 21:07

15

Just use the following

Server.MapPath("~/Data/data.html")

answered Jan 28 '13 at 21:07

Otto Kanellis

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score 4 · Answer 4 · answered Sep 02 '12 at 19:30

4

In the action you can call:

this.Request.PhysicalPath

that returns the physical path in reference to the current controller. If you only need the root path call:

this.Request.PhysicalApplicationPath

answered Sep 02 '12 at 19:30

developer10214

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score 1 · Answer 5 · answered Jun 21 '18 at 15:42

In your controller use:

var path = HttpContext.Server.MapPath("~/Data/data.html");

This allows you to test the controller with Moq like so:

var queryString = new NameValueCollection();
var mockRequest = new Mock<HttpRequestBase>();
mockRequest.Setup(r => r.QueryString).Returns(queryString);
var mockHttpContext = new Mock<HttpContextBase>();
mockHttpContext.Setup(c => c.Request).Returns(mockRequest.Object);
var server = new Mock<HttpServerUtilityBase>();
server.Setup(m => m.MapPath("~/Data/data.html")).Returns("path/to/test/data");
mockHttpContext.Setup(m => m.Server).Returns(server.Object);
var mockControllerContext = new Mock<ControllerContext>();
mockControllerContext.Setup(c => c.HttpContext).Returns(mockHttpContext.Object);
var controller = new MyTestController();
controller.ControllerContext = mockControllerContext.Object;

How do I resolve a path relative to an ASP.NET MVC 4 application root?

5 Answers5

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