This article will demonstrate how to create a file repository. The file repository accomplishes two things. First, it the allows the web administrator to delegate management of file availability to administrative users through FTP uploading rights without permissions for structural changes, and without having to modify the web site. Second, the repository protects the directory structure of the machine, avoiding problems that arise when directory browsing is turned on. The repository allows the web administrator to give additional instructions to the user, unlike the clumsy readme.txt stored in a FTP site. Finally the file repository only offers predefined file extensions for download, protecting the name of other extensions at the web administrators request.
The file repository uses the FileSystem Object available in Internet Information Server version 4.0 to traverse a directory on the hard drive displaying certain file types through an Active Server page.
What does it look like?
Each dynamic directory listing through the ASP script is generated from the requested subdirectory. The script can work off of one or many separate subdirectories arranged in any structure under the file container directory.
Figure 1 : The User's Perspective
The application must be transparent to the users. For the person who wishes to download a file from the file repository the interface looks exactly like a simple HTML page containing a list of links to downloadable files.
Setting Up
To set up the application, create a dedicated directory on your web and make it an FTP virtual directory. This is required to allow your publishers or remote maintainer to logon into the container directories with their FTP clients for the purpose of file uploading. In order for this weblication to work you need to have two directories, each a child of a parent directory dedicated to the repository.
One directory must have scripting privileges. This directory will contain the Active Server page that the user will call to view the repository. There is only one Active Server page, called dir.asp, for every repository implementation. The incoming parameter to it tells it what repository, or what subdirectory, to look in.
Another directory needs to be created as a container for the subdirectories that will hold the files in the repository. For every repository a separate subdirectory needs to be created in the main parent. In the example a "files" directory is created; to have two repositories you will need to have a "files/rep1" and a "files/rep2."
The files placed in the second directory will be displayed to the user. The parent directory needs to have read permissions, and contains the default page, the error pages and the graphics for the site.
Follow these instructions for creating the directory structure:
Create a parent directory called repository in c:\inetpub\
Create a second directory out of the repository directory called scripts.
Give the scripts directory scripting permission. Here is how to do it in IIS 4.0:
Open up MMC.
Expand the default web server.
Expand the repository directory.
Click on the scripts directory to highlight it.
Right click and choose properties from the drop down menu.
Click on the Directory Tab.
Under Application Settings click on Create to create a web application.
Under Application Settings make sure the Script radio button is highlighted.
Click on OK.
Leave MMC open; you will need to use it later.
Now create another directory called files under repository parent directory.
Give the files directory read permission. Here is how to do it in IIS 4.0:
From the open up MMC.
Expand the default web server.
Expand the repository directory.
Click on the files directory to highlight it.
Right click and choose properties from the drop down menu.
Click on the Directory Tab.
Under Access Permission make sure that the Read box is checked.
Click on OK.
Close MMC.
Once you have the directories created you can place dir.asp (shown in Example 1) in the scripts directory.
Example 1 dir.asp
<%
if request.QueryString("path")="" then
response.redirect("no_path.htm")
end if
subDir=request.QueryString("path")
%><html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Directory Listing</title>
</head>
<body bgcolor="#FFFFFF">
<%
if request.QueryString("title")="" or _
isEmpty(request.QueryString("title")) then
%>
<h2 align="center"><%=subDir%></h2><br>
<%else%>
<h2 align="center"><%=request.QueryString("title")%></h2><br>
<%end if%>
<hr>
<p><font size="2">Please click once on the description of the
file that interests you. A dialog box will pop up asking:
"What do you want to do with this file?
" Select "<strong>open it</strong>."
The file will be downloaded and your application will open.
From here you may view it, print it, or
save it (using the "<strong>save as...</strong>"
option) to your hard drive.</font><br>
</p>
<hr>
<div align="center"><center>
<table border="0" cellpadding="6" cellspacing="0" width="550">
<%
Set fileIO = CreateObject("Scripting.FileSystemObject")
path=Server.Mappath("/")
path=path & subDir
Set Dir=fileIO.GetFolder(path)
Set FileCollect=Dir.Files
For Each item in FileCollect
Fsize=item.size
Fname=item.name
FileName=split(Fname,".",2)
title=FileName(0)
short_title=split(title,"_",2)
link="../../" & subdir & FName
%>
<tr>
<% select case FileName(1)
Case "html"%>
<td align="center">
<img src="../icons/html.gif" width="32" height="32" border="0">
</td>
<td align="default"><strong>
<a href="<%=link %>">
<%=short_title(1)%></a>
</strong></td>
<td align="right"><%=Fsize%> bytes</td>
<% Case "doc"%>
<td align="center">
<img src="../icons/word.gif" width="32" height="32" border="0">
</td>
<td align="default"><strong>
<a href="<%=link %>">
<%=short_title(1) %></a>
</strong></td>
<td align="right"><%=Fsize%> bytes</td>
<% Case "xls"%>
<td align="center">
<img src="../icons/excel.gif" width="32" height="32" border="0">
</td>
<td align="default"><strong>
<a href="<%=link %>"><%=short_title(1) %></a>
</strong></td>
<td align="right"><%=Fsize%> bytes</td>
<% Case "exe"%>
<td align="center">
<img src="../icons/pkzip.gif"
width="32" height="32" border="0"></td>
<td align="default"><strong>
<a href="<%=link%>"><%=short_title(1) %></a>
</strong></td>
<td align="right"><%=Fsize%> bytes</td>
<% end select %>
</tr>
<%
Next
set fileIO=Nothing
%>
</table>
</center></div>
</body>
</html>
The script starts by verifying that it has been passed a directory name in the URL header. This directory name is used to reference a child directory of the "files" directory. dir.asp displays all the files in the directory that is passed in.
Making a list of links that point to individual directories can create all the repositories. A call can be issued by clicking directly on a link that includes the path to the directory, which the user wishes to browse. In any case the query string, by which the ASP script is called, has to include a variable named "Path" containing the relative path to the desired folder. If it is not present the file redirects to an error screen in the root of the repository, called no_path.htm. (There is an example of this file in the download available at the end of the article.) Place the file in the repository directory.
The script allows a title for the browsing directory. For instance, the HTML link in Fig.2 would direct the dir.asp to the /lizards/big/ directory and title the resulting page as "Info about Big Lizards":
Example 2 : Link to directory contents display
<a href="file_browser.asp?title=Info+about+Big+Lizards&path=%5Crepository%5Cfiles%5Clizards%5Cbig">
Big Lizards Directory</a>
Note that the attached title and directory has to be URL encoded so that slashes become %5C and spaces become ‘+’ signs.
After displaying the title, if it exists, the script proceeds to the File System Object creation. If the title is not in the query string, the script will default to displaying the path itself. The file system capabilities and related objects have been expanded in the VBScript engine implemented in IIS 4.0 (IIS 3.0 can be upgraded to comply with this expanded capability through an upgrade of the scripting engine to version 3.1 or higher)
The Server.Mappath("/") method returns the physical path to the wwwroot directory on the server. The path to the folder containing the files is concatenated to the string of the root path. A directory object is then extracted through the use of the GetFolder method of the file system object. The file collection object, within the folder, is extracted, in turn, from the directory by accessing the Files property.
Now all that is left to do is iterate through the file collection with the For Each loop and identify the files and their properties. For convenience the extension of the file is removed to be later replaced with a graphical icon identifying a known file type. Note that the split function parses the string and inserts its separated parts into an array. We use the Select case structure to check for expected file extensions and display the appropriate icon next to those files.
File Naming Convention:
To include information that can not be conveyed through the usual properties of the files we use a naming convention for the file names. To begin with we use long names. Note that the words should be spaced by underscores to minimize any potential problems. The underscores will not appear in the displayed name, because they are shown as a link and in most cases underscored by the browser. A date associated with the file, other than the file creation file, can be attached to the end of the descriptive name. If you wish you may expand on this convention and even use it to manipulate the files, sort them, or hide them. Each filename will start with a short unique code to identify it easily in a directory tree. This code, separated from the rest of the name with an underscore, is stripped away for display purposes.
Download
You can Download the code and create your own file repository.
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