Get virtual path for a full path in asp classic - asp-classic

Question

How can I get the virtual path for a full path in ASP classic. Note that the full path may be under a virtual directory and therefore the simplistic
virtPath = Replace(fullPath, Server.MapPath("/"), "")
method will not work.
Edit: To clarify, an example follows
Full Windows File Path (known):
\\MyServer\MyShare\Web\Site\Logs\Test.txt
My Website has a Virtual directory
called Logs that Points to \\MyServer\MyShare\Web\Site\Logs\.
Virtual Path (unknown): /Logs/Text.txt
Http path (unknown, needed):
http://Site/Logs/Test.txt
The code is in a asp page in the main app, not under any virtual directories. It is located on a separate server from the file in question.
IIS 6.0
How do I find the virtual path from the full file path?

Answer 1

In case anyone's interested, Anthony Jones' answer showed me the way to getting the application's relative root consistently. So if you have a site at http://example.com and a local development equivalent at http://localhost/example, you can find your root with this function:
Function ToRootedVirtual(relativePath)
Dim applicationMetaPath : applicationMetaPath = Request.ServerVariables("APPL_MD_PATH")
Dim instanceMetaPath : instanceMetaPath = Request.ServerVariables("INSTANCE_META_PATH")
Dim rootPath : rootPath = Mid(applicationMetaPath, Len(instanceMetaPath) + Len("/ROOT/"))
ToRootedVirtual = rootPath + relativePath
End Function
You can then call it like this to get the root path:
ToRootedVirtual("/")
Which will return:
/ on example.com
/example/ on localhost/example
You can also use it without the slash:
ToRootedVirtual("")

Answer 2

If I've understood the question.
Assumption
The full path is a path with in the current application or a child application. It is not a path limited to the parent nor a path into a sibling application. The desired path is relative to the current applications path.
Scenario 1
A path such as
"/someApp/someFolder/someSubFolder/file.ext"
should resolve it to:-
"~/someFolder/someSubFolder/file.ext"
(although the ~/ notation isn't something ASP classic understands).
Scenario 2
"/someApp/someSubApp/SomeSubFolder/file.ext"
you still want:-
"~/someFolder/someSubFolder/file.ext"
Scenario 3
The app is the root application of the site:-
"/someFolder/someSubFolder/file.ext"
would still become
"~/someFolder/someSubFolder.file.ext"
Solution
The key to solving this is:-
Dim sAppMetaPath : sAppMetaPath = Request.ServerVariables("APPL_MD_PATH")
For the above set of scenarios this will result in something like:-
"/LM/W3SVC/33230916/Root/someApp"
"/LM/W3SVC/33230916/Root/someApp/someSubApp"
"/LM/W3SVC/33230916/Root"
Also
Dim sInstanceMetaPath: sInstanceMetaPath = Request.ServerVariables("INSTANCE_META_PATH")
will in all the scenarios return
"/LM/W3SVC/33230916"
With some mathematical reduction we can arrive at the function:-
Function ToAppRelative(virtualPath)
Dim sAppMetaPath : sAppMetaPath = Request.ServerVariables("APPL_MD_PATH")
Dim sInstanceMetaPath: sInstanceMetaPath = Request.ServerVariables("INSTANCE_META_PATH")
ToAppRelative = "~/" & Mid(virtualPath, Len(sAppMetaPath) - Len(sInstanceMetaPath) - 3)
End Function

Answer 3

Although there may be a better way, I always did this by creating a config variable where I manually specify the root path that is not part of the virtual path. This is because you do not know if the site will be deployed as root, under a folder in root web, or in a virtual directory.

Answer 4

well, my answer isn't better than OrbMan's...
I have organized my app in such a way that every include is relative...
that is
instead of \myapp\lib\somefile.asp I use ..\lib\somefile.asp
in other cases I just do what Orbman said...

Answer 5

Here's how you solve root-relatie pathing in html via ASP so your site can be portable to different hosting directories.
This little snippet will produce the correct prefix to set your URLs:
Mid(Request.ServerVariables("APPL_MD_PATH"),Len(Request.ServerVariables("INSTANCE_META_PATH"))+6)
You can use this in LINKs, IMGs, hyperlinks, etc as follows:
<link href="<%= Mid(Request.ServerVariables("APPL_MD_PATH"),Len(Request.ServerVariables("INSTANCE_META_PATH"))+6) %>/assets/css/master.css" rel="stylesheet" type="text/css" />
so, code your paths to be root-relative (starts with a /) and then put this snippet right in front of that first slash, inside the quotes:

Answer 6

The server's virtual path is:
<%Response.Write "http://" & Request.ServerVariables("server_name") &
left(Request.ServerVariables("SCRIPT_NAME"),InStrRev(Request.ServerVariables("SCRIPT_NAME"),"/")) %>
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