Can a .msi file install itself (presumably via a Custom Action)?

Question

I wand to construct an MSI which, in its installation process, will deploy itself along with its contained Files/Components, to the TargetDir.

So MyApp.msi contains MyApp.exe and MyAppBootstrapperEmpty.exe (with no resources) in its File Table.

The user launches a MyAppBootstrapperPackaged.exe (containing MyApp.msi as a resource, obtained from the internet somewhere, or email or otherwise). MyAppBootStrapperPackaged.exe extracts MyApp.msi to a temp folder and executes it via msiexec.exe.

After the msiexec.exe process completes, I want MyApp.msi, MyBootstrapperEmpty.exe (AND MyApp.exe in %ProgramFiles%\MyApp folder so MyApp.exe can be assured access to MyApp.msi when it runs (for creating the below-mentioned packaged content).

MyAppBootstrapper*.exe could try and copy MyApp.msi to %ProgramFiles%\MyApp folder, but would need elevation to do so, and would not allow for its removal via Windows Installer uninstall process (from Add/Remove Programs or otherwise), which should be preserved.

Obviously (I think it's obvious - am I wrong?) I can't include the MSI as a file in my Media/CAB (chicken and egg scenario), so I believe it would have to be done via a Custom Action before the install process, adding the original MSI to the MSI DB's Media/CAB and the appropriate entry in the File table on the fly. Can this be done and if so how?

Think of a content distribution model where content files are only ever to be distributed together with the App. Content is produced by the end user via the App at run time, and packaged into a distributable EXE which includes both the App and the content.

MyApp's installer must remain an MSI, but may be executed by a Bootstrapper EXE. The installed MyApp.exe must have access to both MyApp.msi and EXE is to be "assembled" at runtime by the App from a base (empty) MyAppBootstrapper.exe, which is also installed by the MSI, and the content created by the end-user. The EXE's resource MSI must be the same as that used to install the App which is doing the runtime packaging.

WIX is not to be installed with MyApp.

There can be no network dependencies at run-/packaging- time (i.e. can't do the packaging via a Webservice - must be done locally).

I am familiar with (and using) Custom Actions (managed and unmanaged, via DTF and otherwise).

Answer 1

Add an uncompressed medium to your wxs like this:

<Media Id='2'/>

And then create a component with a File element like this:

<File Source='/path/to/myinstaller.msi' Compressed='no' DiskId='2' />

This will make the installer look for a file called "myinstaller.msi" on the installation medium, in the same folder as the msi that is being installed. The source path above should point to a dummy file, it is only there to appease wix.

Edit: The following sample test.wxs demonstrates that it works. It produces a test.msi file which installs itself to c:\program files\test. Note that you need to put a dummy test.msi file in the same folder as text.wxs to appease wix.

<?xml version='1.0' encoding='utf-8'?>
<Wix xmlns='http://schemas.microsoft.com/wix/2006/wi'>
   <Product
         Name='ProductName'
         Id='*'
         Language='1033'
         Version='0.0.1'
         Manufacturer='ManufacturerName' >
      <Package
            Keywords='Installer'
            Description='Installer which installs itself'
            Manufacturer='ManufactererName'
            InstallerVersion='100'
            Languages='1033'
            Compressed='yes'
            SummaryCodepage='1252'/>

      <Media Id='1' Cabinet='test.cab' EmbedCab='yes'/> 
      <Media Id='2' /> 

      <Directory Id='TARGETDIR' Name="SourceDir">
         <Directory Id='ProgramFilesFolder'>
            <Directory Id='TestFolder' Name='Test' >
               <Component Id="InstallMyself">
                  <File Source="./test.msi" Compressed="no" DiskId="2" />
               </Component>
            </Directory>
         </Directory>
      </Directory>

      <Feature
            Id='Complete'
            Display='expand'
            Level='1'
            Title='Copy msi file to program files folder'
            Description='Test'>

         <ComponentRef Id="InstallMyself" />
      </Feature>

   </Product>
</Wix>

Answer 2

Having one .MSI package launch another .MSI package from "within" itself is called a nested install, and it's bad juju (see Rule 20). Windows Installer has some global data that it uses to manage the current install, and it doesn't handle well multiple installs at the same time. For the same reason, if you start one install and then try to start another while the first is still in progress, you'll usually see a pop-up to the effect of "another install in progress, please wait until it's done".

You can have a program, usually called a bootstrapper (I think that's what you're referring to) which is itself not an install package, but which contains an install package (such as an .MSI or an .EXE) as a resource, possibly compressed. The action of the bootstrapper program is to extract/expand the resource to a file, commonly in a %TEMP% directory, then either launch the extracted .EXE or run MSIEXEC on the extracted .MSI. The bootstrapper can contain multiple resources and extract+install them one by one, if you need to install prerequisites before the main package. Or you can ship multiple packages as separate files, and have the bootstrapper execute/install them directly from the distribution media one by one, or copy them down to the target machine and run the series of install from there, or...

WiX itself does not get installed, no. It's a tool with which .MSI packages can be built. The WiX project has on its wishlist a generic bootstrapper program, but it hasn't been implemented yet. There are other bootstrappers available, e.g. this one.

You won't need a custom action -- in fact, since the bootstrapper isn't itself a Windows Installer installation package, "custom action" has no meaning to it. And, if you're familiar enough with CAs to know about managed/unmanaged/DTF, then you know enough to avoid custom actions whenever you can. (grin)

Answer 3

I think it's much easier for your bootstrapper to extract MSI file to some predefined location rather than to the temp folder. For example, to C:\Documents and Settings\All Users\Application Data\My Company\My Product Install Cache. After installation finishes bootstrapper would leave MSI file sitting there. If at some stage user decides to reinstall your product Windows Installer will be able to locate source MSI file.

Also, add path to this file to RemoveFile table so that it gets deleted on uninstall. You can use RemoveFile element in WiX for that.

Answer 4

So if I understand, then I think I would have the app create a transform (MST) that has the content files and apply that to the base MSI. I'm still not convinced that I understand though. :)

Answer 5

I'd configure the MSI cache path to a known location.

Then at runtime if you need to "edit" the MSI use VBScript or similar.

But still, I ask WHY!?!

Answer 6

I am also working on a way to deploy multiple MSI files. I have a bootstrapper.exe program that bundles the MSI files and runs them one at a time. This solves my problem for most cases.

The case it does not solve is GPO (Global Policy Object) distribution of the install. GPO requires a dot-msi file to run an install.

To do this here's what I did which almost solved the problem (but not quite). I put the dot-msi files in the file table of an installer and put my bootstrapper in the binary table and run it from a custom action inserted after InstallFinalize in the InstallExecuteSequence. Of course the bootstrapper won't be able to run other MSI's because the top level MSI holds the _MSIExecute mutex.

It was pretty easy to get a little further. I made the bootstrapper return control to the top level installer and continute. And then I added a WaitForSingleObject call to wait for the top level install to finish, and the bootstrapper can then continue to finish the install.

My problem is that the GPO installation happens at boot time and the top level install completes before the sub installers are done and GPO reboots the machine.

The toplevel install also returns a success status when the install may actually fail later on.

I'm still looking for a way to block the top level install from completing until after the bootstrapper completes.