Creating a Standalone Offline Chocolatey Installer

The Chocolatey install documentation includes a section about why there isn't an MSI to install Chocolatey. In case that you are still searching for an executable, this post outlines a way to create your own "setup" using a self extracting 7-zip archive. We'll need the following directory structure:

config.txt

We're using a rather simple configuration, which will:

  • Show the user a "Do you want to install Chocolatey?" yes/no prompt
  • Run install.bat after extracting the archive

The 7-zip SFX documentation outlines all available format options of a config.txt file. 

;!@Install@!UTF-8!
Title="Chocolatey"
BeginPrompt="Do you want to install Chocolatey?"
ExecuteFile="install.bat"
;!@InstallEnd@!

install.bat

install.bat is a simple wrapper script which calls install.ps1. I found this to be more convenient than trying to let the 7-zip SFX module call PowerShell directly. 

@ECHO OFF
PowerShell.exe -NoProfile -ExecutionPolicy Bypass -Command "& '%~dpn0.ps1'"
PAUSE

install.ps1

This script performs the actual installation by calling Chocolatey's chocolateyInstall.ps1. 

if ($env:ChocolateyInstall) {
    Write-Warning 'Chocolatey is already installed!'
    return
}

$env:ChocolateyInstall = "$($env:ProgramData)\chocolatey"

$root = if ($PSScriptRoot) { $PSScriptRoot } else { Split-Path -Path $psISE.CurrentFile.FullPath }

& (Join-Path $root 'chocolatey\tools\chocolateyInstall.ps1')

build.ps1

This script does a few things for us. It will:

  • Download Chocolatey (v0.10.13) and extract it in a temp directory
  • Download and extract the 7-zip SFX module in a temp directory
  • Create the 7-zip archive output\chocolateySetup.7z containing Chocolatey, install.ps1 and install.bat
  • And finally, create the executable output/chocolateySetup.exe by combining output/chocolateySetup.7z, config.txt and the 7-zip SFX module

All calls to 7-zip are wrapped in an exec function, which I've described in a previous post.

You can tweak the $chocoUrl parameter to download a different version of Chocolatey. Keep in mind that you might need to delete the temp directory to remove all "cached" files. 

$ErrorActionPreference = 'Stop'
Set-StrictMode -Version 'Latest'

function exec {
    param(
        [Parameter(Mandatory = $true)]
        [scriptblock]$ScriptBlock,
        [int[]]$ValidExitCodes = @(0)
    )

    $global:LASTEXITCODE = 0

    & $ScriptBlock

    if (-not ($global:LASTEXITCODE -in $ValidExitCodes)) {
        throw "Invalid exit code: $($global:LASTEXITCODE)"
    }
}

$root = if ($PSScriptRoot) { $PSScriptRoot } else { Split-Path -Path $psISE.CurrentFile.FullPath }

$configFile = Join-Path $root 'config.txt'
$chocoUrl = 'https://chocolatey.org/api/v2/package/chocolatey/0.10.13'
$lzmaUrl = 'https://www.7-zip.org/a/lzma1900.7z'

$outputDir = Join-Path $root 'output'
$tempDir = Join-Path $root 'temp'
$installerFile = Join-Path $outputDir 'chocolateySetup.exe'

if (Test-Path $outputDir) {
    Remove-Item $outputDir -Recurse -Force
}

New-Item $outputDir -Type Directory -Force | Out-Null
New-Item $tempDir -Type Directory -Force | Out-Null

$chocoDir = Join-Path $tempDir 'chocolatey'

if (-not (Test-Path $chocoDir)) {
    $chocoZipFile = Join-Path $tempDir 'chocolatey.zip'
    Invoke-WebRequest -Uri $chocoUrl -OutFile $chocoZipFile
    Expand-Archive -Path $chocoZipFile -DestinationPath $chocoDir
}

$sfxFileName = '7zS2.sfx'
$sfxFile = Join-Path $tempDir $sfxFileName

if (-not (Test-Path $sfxFile)) {
    $lzmaFile = Join-Path $tempDir 'lzma.7z'
    Invoke-WebRequest -Uri $lzmaUrl -OutFile $lzmaFile
    exec { 7z e $lzmaFile $sfxFileName -r -o"$tempDir" }
}

$installerZipFile = Join-Path $outputDir 'chocolateySetup.7z'

exec { 7z a $installerZipFile (Resolve-Path $chocoDir) }
exec { 7z a $installerZipFile 'install.bat' }
exec { 7z a $installerZipFile 'install.ps1' }

Get-Content $sfxFile, $configFile, $installerZipFile -Encoding Byte -Read 512 | Set-Content $installerFile -Encoding Byte

Usage

Given the above files, call build.ps1 to create output\chocolateySetup.exe. Run the setup file, confirm the UAC prompt and the "Do you want to install Chocolatey?" dialog to start the install process.

There's currently only one drawback that I'm aware of: After running the installer, Windows might pop up a "This program might not have installed correctly" message, even if the overall installation might be successful. Others have reported similar problems on superuser and StackOverflow.

Published: 2019-09-27