Easy Parsing of Setting Files (Part 3)

In the previous tip you have discovered how ConvertFrom-StringData can turn plain text key-value pairs into a hash table. What’s missing is the other way: turn a hasht able into plain text. With that in place, you’d have a really simple framework to save settings and information to files.

Let’s first create a hash table with some data:

$test = @{
    Name = 'Tobias'
    ID = 12
    Conf = 'PowerShell Conference EU'
}

$test

The result looks like this:

 
Name                           Value                                                                                        
----                           -----                                                                                        
Conf                           PowerShell Conference EU                                                                     
Name                           Tobias                                                                                       
ID                             12
 

Now here is the function ConvertFrom-Hashtable that takes a hash table and converts it to plain text:

filter ConvertFrom-Hashtable
{
    $_.GetEnumerator() |
      ForEach-Object {
        # get hash table key and value
        $value = $_.Value
        $name = $_.Name
        
        # escape "\" in strings
        if ($value -is [string]) { $value = $value.Replace('\','\\') }
        
        # compose key-value pair as plain text
        '{0}={1}' -f $Name, $value
      }
}

Let’s see how the hash table converts:

 

PS> $test | ConvertFrom-Hashtable
Conf=PowerShell Conference EU
Name=Tobias
ID=12

PS>  
 

You can use ConvertFrom-StringData to go the other way:

 
PS> $test | ConvertFrom-Hashtable | ConvertFrom-StringData

Name                           Value                                                                                        
----                           -----                                                                                        
Conf                           PowerShell Conference EU                                                                     
Name                           Tobias                                                                                       
ID                             12                                                                                           



PS>  
 

So essentially, you can now take your hash table, save it as plain text, and reuse it later:

$test = @{
    Name = 'Tobias'
    ID = 12
    Conf = 'PowerShell Conference EU'
}

$path = "$env:temp\settings.txt"

# save hash table as file
$test | ConvertFrom-Hashtable | Set-Content -Path $path -Encoding UTF8
notepad $path 

# read hash table from file
Get-Content -Path $path -Encoding UTF8 |  
  ConvertFrom-StringData |
  Out-GridView

Note that this approach works well for simple string and numeric data. It will not work for complex data types since the conversion does not serialize objects.

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