How to use Server.MapPath when HTTPContext .Current is Nothing

Question

I have some code that works fine when I need to delete some image files from a directory on my web server:

Dim ImageURL As String = dsImages.Tables(0).Rows(iImgRow).Item("ImageURL")
Dim physicalName = Server.MapPath(ImageURL)
oUpload.DeleteFileFromServer(physicalName, iAdid, iImgID)

..but I am running into a problem when a maintenance task running in a separate thread at set intervals determines that files like the above need to be deleted:

Dim ImageURL As String = dsImage.Tables(0).Rows(i - 1).Item("ImageURL")
Dim iImgID As Integer = dsImage.Tables(0).Rows(i - 1).Item("ImageId")
Dim physicalName As String = HttpContext.Current.Server.MapPath(ImageURL)
oUpload.DeleteFileFromServer(physicalName, iAdID, iImgID)

In this latter case, HttpContext.Current.Server.MapPath(ImageURL) has a value of Nothing.

Is there a way to get the full path for this case?

Johnstone

Possible duplicate of How can I use Server.MapPath() from global.asax? – Richly

Answer 1

Assuming that the paths are relative then the separate process does not know what they are relative to, which web application. In this case you will need to store it in the config and either append the two together or perform a string replace on ~/

Damnation

Found a better answer at: #936440 - but I don't know the best way to close this question. – Johnstone

Nice, learnt something new there. I think you just leave the question to die now. – Damnation

Answer 2

The HttpContext.Current is not available when your code is running inside a thread.

To have your web application path you can either use :

System.Web.Hosting.HostingEnvironment.MapPath("~/")

or you can simply find it in the HttpRuntime.AppDomainAppPath property (recommended/faster).

Moltke

Why is HttpRuntime.AppDomainAppPath recommended/faster? Is it faster in terms of "less code to write"? Or is it faster when running the statement? Is the difference big enough to beat the convenience of not having to concatenate the paths by myself? – Earhart