ASP Scripts to Determine if a Specified File and Folder Exist

Introduction

Here are two VBScript functions that check to see if a specified file or folder exist on the server. As such they can be used to improve error handling on ASP pages that read or write files from disk.

Checking to see if a file exists

The first function (CheckFileExists) checks to see if a file exists. It returns 'True' if the file exists, or 'False' if it does not.

<%
Function CheckFileExists(sFileName)

Dim FileSystemObject

Set FileSystemObject = Server.CreateObject("Scripting.FileSystemObject")

If (FileSystemObject.FileExists(sFileName)) Then
CheckFileExists = True
Else
CheckFileExists = False
End If

Set FileSystemObject = Nothing

End Function
%>

The following code is an example of how to use the function:

<%
If CheckFileExists("D:\ProductionReports\July2002\July-12-2002.xls") Then
Response.Write("The production report for July 2002 is available")
Else
Response.Write("The production report for July 2002 cannot be found")
End If
%>

Checking to see if a folder exists

The second function (CheckFolderExists) checks to see if a folder exists. It returns 'True' if the folder exists, or 'False' if it does not.

<%
Function CheckFolderExists(sFolderName)

Dim FileSystemObject

Set FileSystemObject = Server.CreateObject("Scripting.FileSystemObject")

If (FileSystemObject.FolderExists(sFolderName)) Then
CheckFolderExists = True
Else
CheckFolderExists = False
End If

Set FileSystemObject = Nothing

End Function
%>

The following code is an example of how to use the CheckFolderExists function:

<%
If CheckFolderExists("D:\ProductionReports\July2002") Then
Response.Write("The production reports for July 2002 are available")
Else
Response.Write("The production reports for July 2002 are not available")
End If
%>

Problems with file permissions

A problem with these two functions is the fact that they will check for the existence of files and folders, but do not indicate whether the user has the appropriate permissions to view them.

A way around this problem is to use the Permission Checker Component. This Component is supplied with the Internet Information Server 4.0 Resource Kit, and also with the Internet Information Services 5.0 of Windows 2000. This object has one method - HasAccess, which makes it possible to determine if the user has permission to read a specified file.

An example of using the component is below:

<%
Set PermissionChecker = Server.CreateObject("MSWC.PermissionChecker")

If PermissionChecker.HasAccess("D:\ProductionReports\July2002\July-19-2002.xls") Then
Response.Write("You have permission to view the July 2001 production report")
Else
Response.Write("You do not have permission to view the July 2002 production report")
End If

Set PermissionChecker = nothing
%>

The Permission Checker Component can also be incorporated into the original CheckFileExists function:

<%
Function CheckFileExists(sFileName)

Dim FileSystemObject

Set FileSystemObject = Server.CreateObject("Scripting.FileSystemObject")

If (FileSystemObject.FileExists(sFileName)) Then
Set PermissionChecker = Server.CreateObject("MSWC.PermissionChecker")

If PermissionChecker.HasAccess(sFileName) Then
CheckFileExists = True 
End If

Set PermissionChecker = nothing
Else
CheckFileExists = False
End If

Set FileSystemObject = Nothing

End Function
%>

The function can then be used in a similar way to before:

<%
If CheckFileExists("D:\ProductionReports\July2002\July-12-2002.xls") Then
Response.Write("The production report for July 2002 is available")
Else
Response.Write("The production report for July 2002 cannot be found or you do not have permission to view it")
End If
%>

Further reading

• Further information about the Permission Checker Component is available from Microsoft.

• Sams Teach Yourself Web Development With ASP in 24 Hours. Start learning ASP with this introductory guide.

Useful Development Tools

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SQL Documentation Tool

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Text Workbench

Text Workbench is a file search and replacement utility for text files and Microsoft Office documents. Make rapid file replacements on multiple files and folders full of files. Advanced replacement options include regular expressions support. It even works on remote file systems via FTP. A Regular Expression Laboratory allows advanced pattern matching and replacement expressions to be built and tested. This great utility will make your everyday development tasks much easier!

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Indexing Service Companion

The Indexing Service Companion is a utility that extends the functionality of the Microsoft Windows Indexing Service so that it is able to index content from any remote website and also from ODBC compliant databases. As such it can be used as a low cost alternative to Sharepoint's Search Services.

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ASP Spell Check

ASPSpellCheck is the easy way to add spell checking capabilities to your ASP or ASP.NET websites, Intranets and web applications. The utility allows you to add spell checking capabilities to any HTML text field or rich content editing text box. It works with all common web browsers, and there are no components or databases to install on the server.

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Author details

Brett Burridge has worked as a web developer since 1997 and has developed web applications for a range of corporations, start up busiensses and educational establishments.

Brett is presently employed as an Internet developer and technical writer through his own company, Winnersh Triangle Web Solutions Limited. The company produces a number of innovative products, including a range of software documentation tools, which include the ASP Documentation Tool™, the .NET Documentation Tool for VB.NET and C#, and the SQL Server Documentation Tool. Other products include The Website Utility, which functions as a website error checker, search engine optimizer and ASP/ASP.NET search engine builder application.

As well as the ASPAlliance, Brett has written articles for Ariadne.ac.uk, ASPToday, the software documentation portal www.softwaredocumentation.info, and has contributed recipes to the ASP.NET Developer's Cookbook.    links

Outside web development, Brett is interested in travelling (here are my travel logs from New York, Hong Kong and Tokyo), digital photography (here's my photo gallery), tropical fishkeeping and collecting contemporary works of art by artists such as Doug Hyde.

Contact Brett by emailing

Article history

"ASP scripts to determine if a specified file and folder exist" originally published on ASPWatch.com on October 11 2000. Republished on ASPAlliance.com on 26 September 2001.

ASP Kitchen: ASPWatch.com articles: File and Folder Checkers