PowerShell Import-PowerShellDataFile

last modified February 15, 2025

This article covers the Import-PowerShellDataFile cmdlet in PowerShell. It imports values from a .psd1 file into a hashtable. The cmdlet safely evaluates file contents without executing script blocks.

PowerShell data files basics

PowerShell data files (.psd1) store configuration data in key-value pairs. They are commonly used for module manifests and configuration settings. Unlike scripts, they don't contain executable code. The Import-PowerShellDataFile cmdlet safely imports these files.

Basic Import-PowerShellDataFile usage

The simplest usage imports a data file and returns its contents as a hashtable. Specify the file path with the -Path parameter. The cmdlet parses the file and converts it to a PowerShell object. This is useful for reading configuration files.

$config = Import-PowerShellDataFile -Path "C:\config\settings.psd1"
$config

This imports a configuration file and stores it in the $config variable. The variable contains a hashtable with the file's key-value pairs. You can then access individual values by their keys.

Importing module manifest data

Module manifests (.psd1 files) contain metadata about PowerShell modules. You can use Import-PowerShellDataFile to read this data. This example shows how to access module version information from a manifest.

$manifest = Import-PowerShellDataFile -Path ".\MyModule\MyModule.psd1"
$manifest.ModuleVersion

This command reads a module manifest file and displays its version number. The version is stored in the ModuleVersion property of the returned hashtable.

PS C:\> .\data2.ps1
1.2.0

Accessing nested hashtable values

PowerShell data files can contain nested hashtables. You can access these values using dot notation. This example demonstrates accessing nested configuration settings from a data file.

$config = Import-PowerShellDataFile -Path ".\appsettings.psd1"
$config.Database.Server

This reads a configuration file with nested database settings. It then accesses the server name from the Database section. The dot notation navigates through the nested structure.

Using with splatting

Imported hashtables can be used with PowerShell splatting. Splatting passes parameters to cmdlets using a hashtable. This example shows how to use a configuration file to splat parameters.

$params = Import-PowerShellDataFile -Path ".\mailparams.psd1"
Send-MailMessage @params

This imports mail parameters from a file and splats them to Send-MailMessage. The @ symbol before the variable name indicates splatting. Each key-value pair becomes a parameter-value pair for the cmdlet.

Importing multiple configuration files

You can combine multiple configuration files into a single configuration. This example merges settings from different environment-specific files. The resulting hashtable contains all configuration values.

$baseConfig = Import-PowerShellDataFile -Path ".\config\base.psd1"
$envConfig = Import-PowerShellDataFile -Path ".\config\prod.psd1"
$finalConfig = $baseConfig + $envConfig

This combines base configuration with environment-specific overrides. The + operator merges the two hashtables. Values in the second hashtable override matching keys in the first.

Validating imported data

After importing data, you can validate its structure and values. This example checks for required configuration keys. It throws an error if any are missing.

$config = Import-PowerShellDataFile -Path ".\appconfig.psd1"
$required = @("Server", "Database", "Credentials")
foreach ($key in $required) {
 if (-not $config.ContainsKey($key)) {
 throw "Missing required configuration key: $key"
 }
}

This script ensures all required configuration keys are present. It checks each key in the $required array against the imported configuration. If any key is missing, it throws an exception.

Converting JSON to PowerShell data file

You can convert JSON data to PowerShell data file format. This example shows how to read JSON and save it as a .psd1 file. The converted file can then be imported with Import-PowerShellDataFile.

$json = Get-Content -Path ".\config.json" -Raw | ConvertFrom-Json
$json | ConvertTo-Json -Depth 10 | Out-File ".\config.psd1"

This reads a JSON file, converts it to a PowerShell object, then saves it as a .psd1 file. The -Depth parameter ensures nested structures are preserved. The resulting file can be imported normally.

Source

PowerShell documentation

In this article, we have covered the Import-PowerShellDataFile cmdlet in PowerShell. We demonstrated various use cases for importing configuration data from .psd1 files.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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