Continuing On...

Now that the user can view the hierarchy, we must allow them to check files in and out. Assuming you've used the form from the previous page, let's examine the code that will handle the submission.

<%
dim intFileID, strFileName, intCount, strFunction, strLocation, i
dim strSQL, rst, strConnectionString
dim fso, f

'Set database variables
strConnectionString = "DSN=MySource;UID=username;PWD=password;Database=MySourceDB"
set rst = Server.CreateObject("ADODB.Recordset")

intCount = Request.form("file").Count
strFunction = Request.form("function") <-- What did the user
			want to do? (check in, check out, etc)

for i = 1 to intCount
  intFileID = Request.form("file")(i) <-- Grab the file
in question
  strSQL = "SELECT Name, Location FROM tblFiles WHERE FID = " & intFileID
  rst.open strSQL, strConnectionString
  strFileName = rst(0)
  strLocation = rst(1)
  rst.close

  'Use the filesystemobject to get the file in question
  Set fso = CreateObject("Scripting.FileSystemObject")
  Set f = fso.GetFile(strLocation)
  If (f.attributes and 1) AND strFunction = "Checkout" Then <-- If file is read only, 
			then change it to writeable
    f.attributes = f.attributes - 1
  Elseif NOT (f.attributes AND 1) and strFunction = "CheckIn" then <-- Otherwise, 
			make the file read only
    f.attributes = f.attributes + 1
  End If
  f.close
  set fso = nothing

  'Update the database to show which user currently has the file checked out
  strSQL = "SELECT Update SET User = '" & Session("Username") & "' WHERE " & _
    "WHERE FID = " & intFileID
  rst.open strSQL, strConnectionString

next

%>

Let's take a look at the above code. The first thing we do is to loop through all the files the user checked in the previous step. Each item in Request.Form("file") holds the FID that we'll need to grab each file name and location from the database. We then use the file system object (check out a previous article for a tutorial on the FSO) to open each file, and clear its read-only flag, if it isn't cleared already. This is so the user can download a writeable copy of the file, and also upload and overwrite the old file. Finally, we update the database with the proper user information. Pretty simple, huh?

Let's take a step back for a second. Imagine that a user checks out a file, and then downloads it. The application will clear the read-only flag from the file on the server. Now, any other user can write over that file as well! This is a serious drawback in many source control systems today, even in Visual Source Safe. For a web centric application, one solution would be to monitor the download - once the file is downloaded, reset the read-only flag. That way, you could easily build a function to allow only the user who checked the file out to overwrite the file on the web server. Obviously, we can't do this with FTP, so let's take a look at another method.

The Front End
Effective Source Control
Getting Files