Simplest solution to replace a tiny file inside an MSI?

Question

Many of our customers have access to InstallShield, WISE or AdminStudio. These aren\'t a problem. I\'m hoping there is some way I can provide our smaller customers w

Answer 1

Okay, revisiting this question with my own answer providing nice little VB script that will do all heavy lifting. As mentioned in the original question, the aim was provide a simple solution for sysadmin users to make the updates/changes themselves.

Below is a simplified version of the code I'm currently providing to customers

Option Explicit

Const MY_CONFIG = "MyConfigApp.xml"
Const CAB_FILE = "config.cab"
Const MSI = "MyApp.msi"

Dim filesys : Set filesys=CreateObject("Scripting.FileSystemObject")

If filesys.FileExists("temp.tmp") Then filesys.DeleteFile("temp.tmp")
filesys.CopyFile MSI, "temp.tmp"

Dim installer, database, database2, view
Set installer = CreateObject("WindowsInstaller.Installer")
Set database = installer.OpenDatabase ("temp.tmp", 1)
Set database2 = installer.OpenDatabase (MSI, 1)

If Not filesys.FileExists(MY_CONFIG) Then WScript.Quit 2 ' No config file, abort!

Dim objFile, size, result, seq, objCab

' MakeCab object has been depreciated so we fallback to makecab.exe for with Windows 7
On Error Resume Next ' Disable error handling, for a moment
Set objCab = CreateObject("MakeCab.MakeCab.1") 
On Error Goto 0  ' Turn error handling back on

If IsObject(objCab) Then ' Object creation successful - use XP method   
    objCab.CreateCab CAB_FILE, False, False, False
    objCab.AddFile MY_CONFIG, filesys.GetFileName(MY_CONFIG)
    objCab.CloseCab
    Set objCab = Nothing
Else ' object creation failed - try Windows 7 method
    Dim WshShell, oExec
    Set WshShell = CreateObject("WScript.Shell")
    Set oExec = WshShell.Exec("makecab " & filesys.GetFileName(MY_CONFIG) & " " & CAB_FILE)
End If

Set objFile = filesys.GetFile(MY_CONFIG)
size = objFile.Size

Set view = database.OpenView ("SELECT LastSequence FROM Media WHERE DiskId = 1")
view.Execute
Set result = view.Fetch
seq = result.StringData(1) + 1 ' Sequence for new configuration file

Set view = database.OpenView ("INSERT INTO Media (DiskId, LastSequence, Cabinet) VALUES ('2', '" & seq & "', '" & CAB_FILE & "')")
view.Execute

Set view = database.OpenView ("UPDATE File SET FileSize = " & size & ", Sequence = " & seq & ", FileName = 'MYC~2.CNF|MyConfigApp.xml' WHERE File = '" & MY_CONFIG & "'")
view.Execute

database.GenerateTransform database2, "CustomConfig.mst"
database.CreateTransformSummaryInfo database2, "CustomConfig.mst", 0, 0
filesys.DeleteFile("temp.tmp")

Set view = nothing
Set installer = nothing
Set database = nothing
Set database2 = nothing
Set filesys = Nothing
WScript.Quit 0

Update: The MakeCab.MakeCab.1 object has been depreciated, code updated to now work with Windows 7.