Working with Files in ASP
By Stephen Bucaro
When ASP is installed, the FileSystemObject and the TextStream object are automatically
installed along with it. The ASP FileSystemObject allows you to work with drives, folders,
and files on the server. The TextStream object allows you to create, read, and write files.
In certain instances, you may not be sure that a specific file exists. In that case, you
should use the FileSystemObject's FileExists method before attempting to access
the file. Example code for this is shown below.
<%
Dim objFS
Set objFS =
Server.CreateObject("Scripting.FileSystemObject")
If objFS.FileExists("c:\asp\newfolder\newfile.txt") Then
Response.Write "File exists"
Else
Response.Write "File does not exist"
End If
Set objFS = Nothing
%>
When you enter a URL into the address bar in your Web browser, it consists of a domain
name followed by a file path. The URL file path has no relation to the actual file path
on a physical storage device because a website may be located or moved from one physical
storage location to another without changing the URL of any file on that Web site. The
path you enter into a Web browser is a "virtual path".
The ASP Server object represents the Web server itself and has a method named MapPath
that accepts a virtual path and returns the actual physical path. Below is how a call
to the MapPath method looks.
Server.MapPath(path)
For example, you could use the code shown below to determine the actual physical
location of the web server.
<%
Dim strPath
strPath = Server.MapPath("/")
response.write(strPath)
%>
The resulting response from the above code might be "c:\inetpub\wwwroot". Note that
you don't need to create the Server object because if the Web server is running, the
server object already exists.
Generally, you would use the MapPath method to determine the actual physical path of
a file from its virtual path, as shown below.
<%
Dim strPath
strPath = Server.MapPath("/foldername/filename.asp")
response.write(strPath)
%>
If the path argument doesn't start with a slash (/ or \), MapPath assumes that it is
a path relative to the .asp file being processed. For example, if an .asp file located
at the physical path c:\inetpub\wwwroot\myfolder\myfile1.asp calls the MapPath method
with the code shown below.
<%
Dim strPath
strPath = Server.MapPath("../foldername/filename.asp")
response.write(strPath)
%>
The resulting response would be "c:\inetpub\wwwroot\foldername\filename.asp".
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