PowerShell: reading PowerShell Transcript logs

Question

I've started to use the start-transcript in my profile to keep a log of everything I do via the shell.

it's becoming useful for looking back at what changes are made and when they were made. I'm also beginning to use it as the first steps of documentation. I've been commenting the things done in the shell for future reference.

The thing that is proving tricky is the formatting is that of a text doc and is not as easy to read as the shell (error, verbose and warning colours mainly).

I was wondering if anybody uses the Transcript functionality in this way and has a viewer of preference or a script that parses the log file to produce a doc of some sort?

Edit: i'm interested to know why the question has been down voted...

Answer 1

I believe it will be very hard to parse a transcript to create an accurate formatted document. You could however use the console host API to capture (parts of) the screen buffer.

This Windows Powershell blog article describes how this works.

A trivial way to use the (modified) script (Get-ConsoleAsHtml.ps1) is to modify your prompt function, so that all lines from the buffer that haven't been written to your html transcript yet, are saved every time the prompt function is called. The first block of code is the contents of the modified script, the second block of code shows how you can use this script in your profile.

########################################################################################################### 
# Get-ConsoleAsHtml.ps1 
# 
# The script captures console screen buffer up to the current cursor position and returns it in HTML format.
# (Jon Z: Added a startline parameter)
# 
# Returns: UTF8-encoded string. 
# 
# Example: 
# 
# $htmlFileName = "$env:temp\ConsoleBuffer.html" 
# .\Get-ConsoleAsHtml 5 | out-file $htmlFileName -encoding UTF8 
# $null = [System.Diagnostics.Process]::Start("$htmlFileName") 
# 

param (
  $startline = 0
)

# Check the host name and exit if the host is not the Windows PowerShell console host. 
if ($host.Name -ne 'ConsoleHost') 
{ 
  write-host -ForegroundColor Red "This script runs only in the console host. You cannot run this script in $($host.Name)." 
  exit -1 
} 

# The Windows PowerShell console host redefines DarkYellow and DarkMagenta colors and uses them as defaults. 
# The redefined colors do not correspond to the color names used in HTML, so they need to be mapped to digital color codes. 
# 
function Normalize-HtmlColor ($color) 
{ 
  if ($color -eq "DarkYellow") { $color = "#eeedf0" } 
  if ($color -eq "DarkMagenta") { $color = "#012456" } 
  return $color 
} 

# Create an HTML span from text using the named console colors. 
# 
function Make-HtmlSpan ($text, $forecolor = "DarkYellow", $backcolor = "DarkMagenta") 
{ 
  $forecolor = Normalize-HtmlColor $forecolor 
  $backcolor = Normalize-HtmlColor $backcolor 

  # You can also add font-weight:bold tag here if you want a bold font in output. 
  return "<span style='font-family:Courier New;color:$forecolor;background:$backcolor'>$text</span>" 
} 

# Generate an HTML span and append it to HTML string builder 
# 
function Append-HtmlSpan 
{ 
  $spanText = $spanBuilder.ToString() 
  $spanHtml = Make-HtmlSpan $spanText $currentForegroundColor $currentBackgroundColor 
  $null = $htmlBuilder.Append($spanHtml) 
} 

# Append line break to HTML builder 
# 
function Append-HtmlBreak 
{ 
  $null = $htmlBuilder.Append("<br>") 
} 

# Initialize the HTML string builder. 
$htmlBuilder = new-object system.text.stringbuilder 
$null = $htmlBuilder.Append("<pre style='MARGIN: 0in 10pt 0in;line-height:normal';font-size:10pt>") 

# Grab the console screen buffer contents using the Host console API. 
$bufferWidth = $host.ui.rawui.BufferSize.Width 
$bufferHeight = $host.ui.rawui.CursorPosition.Y 
$rec = new-object System.Management.Automation.Host.Rectangle 0,0,($bufferWidth - 1),$bufferHeight 
$buffer = $host.ui.rawui.GetBufferContents($rec) 

# Iterate through the lines in the console buffer. 
for($i = $startline; $i -lt $bufferHeight; $i++) 
{ 
  $spanBuilder = new-object system.text.stringbuilder 

  # Track the colors to identify spans of text with the same formatting. 
  $currentForegroundColor = $buffer[$i, 0].Foregroundcolor 
  $currentBackgroundColor = $buffer[$i, 0].Backgroundcolor 

  for($j = 0; $j -lt $bufferWidth; $j++) 
  { 
    $cell = $buffer[$i,$j] 

    # If the colors change, generate an HTML span and append it to the HTML string builder. 
    if (($cell.ForegroundColor -ne $currentForegroundColor) -or ($cell.BackgroundColor -ne $currentBackgroundColor)) 
    { 
      Append-HtmlSpan 

      # Reset the span builder and colors. 
      $spanBuilder = new-object system.text.stringbuilder 
      $currentForegroundColor = $cell.Foregroundcolor 
      $currentBackgroundColor = $cell.Backgroundcolor 
    } 

    # Substitute characters which have special meaning in HTML. 
    switch ($cell.Character) 
    { 
      '>' { $htmlChar = '&gt;' } 
      '<' { $htmlChar = '&lt;' } 
      '&' { $htmlChar = '&amp;' } 
      default 
      { 
        $htmlChar = $cell.Character 
      } 
    } 

    $null = $spanBuilder.Append($htmlChar) 
  } 

  Append-HtmlSpan 
  Append-HtmlBreak 
} 

# Append HTML ending tag. 
$null = $htmlBuilder.Append("</pre>") 

return $htmlBuilder.ToString()

Example of a profile:

############################################################################################################ 
# Microsoft.PowerShell_profile.ps1 
# 

$docpath = [environment]::GetFolderPath([environment+SpecialFolder]::MyDocuments)
$transcript = "$($docpath)\PowerShell_transcript.$(get-date -f 'yyyyMMddHHmmss').html";
$global:lastloggedline = 0
function prompt { 
 &'D:\Scripts\Get-ConsoleAsHtml.ps1' $global:lastloggedline | out-file $transcript -append;
 $global:lastloggedline = $host.ui.rawui.cursorposition.Y
 "PS $pwd$('>' * ($nestedPromptLevel + 1)) "
}