Convert Text to Object

Today I have another tool in my new battle regarding turning command line tools into PowerShell tools. The bottom line is we want to have objects written to the pipeline. At the PowerShell Deep Dive in Frankfurt there was a suggestion about providing tools to help with the transformation from CLI to PowerShell and this is one of the items I came up with.

Many command line tools write output in a structured format. For example run this command:

C:\> tasklist /fo list

There's an "object" staring at us for each task. As an aside, don't focus on the command line tool I'm using, pay attention to the technique. To turn output like this into ah object we simply need to split each line at the colon. The first index of the array will be the "property" name and the second index is the value. Here's the function I pulled together.

Function Convert-TextToObject {

<#
This function takes a collection of simple delimited lines and
turns them into an object. The function assumes a single delimiter.
The default delimiter is the colon (:). The item to the left will be
the property and the item on the left will be the property value.

Use $GroupCount to keep track of items that come in groups and write a new object
when the count has been reached. For example, this allows you to pipe
in a long collection of strings and turn every 5 into an object.

tasklist /s server01 /fo list | where {$_} | convert-texttoobject -group 5
#>

[cmdletbinding(SupportsShouldProcess=$True)]

param (
[Parameter(Position=0,Mandatory=$True,HelpMessage="Enter a string to be parsed into an object",
ValueFromPipeline=$True)]
[ValidateNotNullorEmpty()]
[string[]]$Text,
[string]$Delimiter=":",
[int]$GroupCount
)

Begin {
Write-Verbose "Starting $($myinvocation.mycommand)"
#define a hashtable
$myHash=@{}
if ($GroupCount) {
Write-Verbose "Grouping every $GroupCount items as an object"
}
#start an internal counter
$i=0
}

Process {

Foreach ($item in $text) {

if ($i -lt $GroupCount) {
$i++
}
else {
#reset
$i=1
}

#split each line at the delimiter
$data=$item.Split($delimiter)
#remove spaces from "property" name
$prop=$data[0].Replace(" ","")

#trim
$prop=$prop.Trim()
$val=$data[1].Trim()

#add to hash table
Write-Verbose "Adding $prop to hash table with a value of $val"
$myHash.Add($prop,$val)

#if internal counter is equal to the group count
#write the object and reset the hash table
if ($i -eq $groupCount) {
New-Object -TypeName PSObject -Property $myHash
$myHash.Clear()
}

} #foreach
}
End {
#create new object from hash table
if ($myHash.count -gt 0) {
New-Object -TypeName PSObject -Property $myHash
Write-Verbose "Ending $($myinvocation.mycommand)"
}
}

} #end function

The function processes each incoming line of text and splits it on the delimiter. The default is the colon since many CLI tools seem to use it.

#split each line at the delimiter
$data=$item.Split($delimiter)

Since I prefer property names without spaces I remove them from index 0 of the array. I've also found it helpful to trim everything to eliminate extra white space.

#remove spaces from "property" name
$prop=$data[0].Replace(" ","")

#trim
$prop=$prop.Trim()
$val=$data[1].Trim()

Each line is then added to a hash table.

#add to hash table
Write-Verbose "Adding $prop to hash table with a value of $val"
$myHash.Add($prop,$val)

When the hash table is complete it is used to create a new object.

New-Object -TypeName PSObject -Property $myHash

The other "trick" I added is to group lines into an object. This let's me take say every 5 lines of text and make that a single object. I create a counter and increment it whenever a line is processed. When the counter meets the limit, the object is created, the hash table is cleared and the process repeats.

#if internal counter is equal to the group count
#write the object and reset the hash table
if ($i -eq $groupCount) {
New-Object -TypeName PSObject -Property $myHash
$myHash.Clear()
}

Now I can run a command like this:

PS D:\scripts> tasklist /fo list | where {$_} | Convert-TextToObject -group 5

Session# : 0
SessionName : Services
PID : 0
MemUsage : 24 K
ImageName : System Idle Process

Session# : 0
SessionName : Services
PID : 4
MemUsage : 96 K
ImageName : System

Session# : 0
SessionName : Services
PID : 412
MemUsage : 1,164 K
ImageName : smss.exe
...

The output looks similar but now I have objects so I can take advantage of PowerShell. Here are some examples:

tasklist /fo list | where {$_} | Convert-TextToObject -group 5 | ft -auto
tasklist /fo list | where {$_} | Convert-TextToObject -group 5 | group SessionName
tasklist /s $computer /fo list | where {$_} | Convert-TextToObject -GroupCount 5 | Add-member not
eproperty Computername $computer -pass | Export-CSV taskreport.csv

This is by no means perfect but I'd like to think it is a good start. For example, one downside is that all properties are strings where it would be nicer to have properties of an appropriate type. Still, I hope you'll try this out and let me know what you think.

Download Convert-TexttoObject

Update
A newer version of the script can be found at https://jdhitsolutions.com/blog/2012/01/convert-text-to-object-updated/

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