blindpete's posterous

Converting PowerShell data into an HTML report and save it to disk with no need for extra pipeline has long been my dream. Unfortunately, there’s no native Export-HTML cmdlet (unlike, say, Export-CSV), and ConvertTo-HTML does not have -Path parameter and only displays the html code on the screen (very useful ) unless you pipe it to Out-File.

So being inspired by Kirk adding parameters to Import-CSV and using PowerShell 2.0 code-snippets, I created my Export-HTML function, which behaves exactly like ConvertTo-HTML but adds optional -Path parameter to specify the output file.

Download it, copy/paste the function into PowerShell (or dot-source it, or include it in your PowerShell profile) and you will be able to do something like:

Get-Process | Export-Html -Path C:\pr.htm

or

Get-Process |
    Export-Html C:\pr.htm -Title ‘My Processes’

or

Get-Process |
    Export-Html C:\pr.htm -Property Name, Handles -Title ‘My Processes’

You can download the code here, or copy/paste it from the text below.

You may also consider renaming the function name from Export-HTML to ConvertTo-HTML (or use set-alias to make them the same thing), because the -Path parameter is optional, and old behavior of outputting HTML code to the console/pipeline is supported as well as all native parameters.

Here’s how I created this proxy function:

1. Downloaded and installed PowerShell 2.0 code snippets.
2. Used the function (proxy) snippet to generate the proxy for ConvertTo-
HTML.
3. Added Path to the parameters section:

[Parameter(Position=0)]
    [Alias('PSPath', 'FilePath')]
    [ValidateNotNullOrEmpty()]
    [System.String]
    ${Path},

Added a variable to store modified PowerShell code to be executed:

$scriptCmdPipeline = ''

Added parameter handling in which I (if Path is present) append the Out-File code to the pipeline:

if ($Path) {
            $PSBoundParameters.Remove('Path') | Out-Null
            $scriptCmdPipeline += " | Out-File -FilePath $Path"
        }

Got the original command-line for ConvertTo-HTML

$scriptCmd = {& $wrappedCmd @PSBoundParameters}

And added this new pipeline to it:

$scriptCmd = $ExecutionContext.InvokeCommand.NewScriptBlock(
                [string]$scriptCmd + $scriptCmdPipeline
            )

The rest was handled by the code snippet.

Here’s the resultant code:

#Requires -Version 2.0

<#
    Export-Html behaves exactly like native ConvertTo-HTML
    However it has one optional parameter -Path
    Which lets you specify the output file: e.g.
    Get-Process | Export-Html C:\temp\processes.html
#>

function Export-Html {
[CmdletBinding(DefaultParameterSetName='Page')]
param(
    [Parameter(ValueFromPipeline=$true)]
    [System.Management.Automation.PSObject]
    ${InputObject},

# Adding Path parameter 
# (made it Position 0, and incremented Position for others)
    [Parameter(Position=0)]
    [Alias('PSPath', 'FilePath')]
    [ValidateNotNullOrEmpty()]
    [System.String]
    ${Path},

    [Parameter(Position=1)]
    [ValidateNotNullOrEmpty()]
    [System.Object[]]
    ${Property},

    [Parameter(ParameterSetName='Page', Position=4)]
    [ValidateNotNullOrEmpty()]
    [System.String[]]
    ${Body},

    [Parameter(ParameterSetName='Page', Position=2)]
    [ValidateNotNullOrEmpty()]
    [System.String[]]
    ${Head},

    [Parameter(ParameterSetName='Page', Position=3)]
    [ValidateNotNullOrEmpty()]
    [System.String]
    ${Title},

    [ValidateSet('Table','List')]
    [ValidateNotNullOrEmpty()]
    [System.String]
    ${As},

    [Parameter(ParameterSetName='Page')]
    [Alias('cu','uri')]
    [ValidateNotNullOrEmpty()]
    [System.Uri]
    ${CssUri},

    [Parameter(ParameterSetName='Fragment')]
    [ValidateNotNullOrEmpty()]
    [Switch]
    ${Fragment},

    [ValidateNotNullOrEmpty()]
    [System.String[]]
    ${PostContent},

    [ValidateNotNullOrEmpty()]
    [System.String[]]
    ${PreContent})

begin
{
    try {
        $outBuffer = $null
        if ($PSBoundParameters.TryGetValue('OutBuffer', [ref]$outBuffer))
        {
            $PSBoundParameters['OutBuffer'] = 1
        }
        $wrappedCmd = $ExecutionContext.InvokeCommand.GetCommand('ConvertTo-Html',
            [System.Management.Automation.CommandTypes]::Cmdlet)

        # define string variable to become the target command line
        #region Initialize helper variable to create command
        $scriptCmdPipeline = ''
        #endregion

        # add new parameter handling
        #region Process and remove the Path parameter if it is present
        if ($Path) {
            $PSBoundParameters.Remove('Path') | Out-Null
            $scriptCmdPipeline += " | Out-File -FilePath $Path"
        }
        #endregion

        $scriptCmd = {& $wrappedCmd @PSBoundParameters}

        # redefine command invocation
        #region Append our pipeline command to the wrapped command script block
        $scriptCmd = $ExecutionContext.InvokeCommand.NewScriptBlock(
                [string]$scriptCmd + $scriptCmdPipeline
            )
        #endregion

        $steppablePipeline =
          $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin)
        $steppablePipeline.Begin($PSCmdlet)
    } catch {
        throw
    }
}

process
{
    try {
        $steppablePipeline.Process($_)
    } catch {
        throw
    }
}

end
{
    try {
        $steppablePipeline.End()
    } catch {
        throw
    }
}
<#

.ForwardHelpTargetName ConvertTo-Html
.ForwardHelpCategory Cmdlet

#>}

Hope you find this useful and it gets you the feature you wanted without waiting for PowerShell v3.

Tags: ConvertTo-HTML, Examples, Export-HTML, PowerGUI, PowerShell, PowerShell v2, Proxy functions, cmdlets
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