Cash Foley Blog

My 2010 Audible books.

2011-01-17T12:19:33.364-05:00

It was another incredible year of listening on Audible.com. Hear (ha) is the list of 29 books I listened to in 2010.

The Millennium Trilogy from Stieg Larsson :

This series is outstanding. The characters are intriguing, the plot draws you in and you can’t wait to find out what happens next. I saw last week these books are the top 3 in the USA Today 2010 book list. Unfortunately, the author died shortly after publishing the trilogy so we can’t expect more in the near future.

Infidel by Ayaan Hirsi Ali
This one made me down right nervous to start. I had heard about the mutilating ‘female castration’ as a young girl in Somalia and it made me cringe to even think about the subject. Also, the book is read by the author which had the potential of being a painful experience fighting through a thick accent. As it turns out, this book was one of the most inspiring I have ever read/heard. I admire this woman for her strength of character and intelligence. She famously gets elected to the Dutch Parliament and is outspoken on the violence towards women infused in the Islamic religion and Muslim culture. This draws the wrath of Islamic fundamentalist leading to death threats and the Dutch government attempting to quiet everything up by revoking her citizenship on a technicality. This is the part of her story that was newsworthy. Her story is inspiring and worthwhile even if she had never been famous. It is truly amazing she was able to un-root herself from her culture and religion and spring forth as inspiration of reason and freedom.

The Ascent of Money by Niall Ferguson
Admittedly I’m still listening to this one. So far, it is one of the very best economic books I’ve listened to – and I’ve listened to dozens As such, I don’t know where he ends up but his narrative and technical detail make it as compelling as Milton Friedman.

In Cold Blood by Truman Capote
I had been reluctant to listen to Capote because of all the strange impressions I had of him from when I grew up in the 70’s. He seemed so intellectually pretentious I really didn’t want to get talked down to for hours on end. As it turned out, it was one of my favorites for the year. Even though the outcome is known, the story was thoroughly compelling. In fact, foretelling the outcome and leaving hanging on how it gets there is the primary narrative style. It is interestingly an anti-death penalty statement without sugar coating the ruthless anti-social non-redeeming value of these cold blooded killers.

The Historical Novel series by Jeff Shaara and the one that started it all by his father Michael Shaara , The Killer Angels . These Novels comprise one of the greatest narratives of our history. They are written as a novel where the author re-creates scenes and thoughts of the characters that while not ‘pure history’ are as accurate as any known historical treatments of the subject matter. I make a conscious effort to mix my listening with Fiction and non-Fiction. Luckily with these novels I felt the satisfaction of both. This isn’t to say I consider these less the factual. As you can infer from the fact I chewed up 8 of these, I found them to engrossing and entertaining.

A pair of books from Byron Katie was among the most thought provoking and emotionally impacting I have ever experienced. I Need Your Love, Is That True? and Loving What Is have had huge impact on how ‘perceive’ and experience relationships. I won’t even try to summarize them in this short space. I will say that it is an amazing process for questioning thoughts and defusing the pain you are ‘giving yourself’ – usually under the belief that others are giving you. I did listen to Making Your Thoughts Work For You but this one didn’t work as well for me. “Dr. Dyer” dominated the presentation and pretty close to a waste of time.

The Road to Serfdom by Friedrich A. Hayek
Hayek is great. He wrote this book during WWII. He relentlessly refutes the economic premises behind National Socialism, Communism and Socialism. He makes it clear how similar these economic systems are to each other rather than the “extreme right” and “extreme left” taught to us today. Unfortunately the hard lessons he demonstrates are being re-enacted in today’s political environment.

13 Things That Don't Make Sense by Michael Brooks
There were parts that were good. However, it was not one of my favorite of the year. Science is tough enough when your goal is to make sense of things. When it comes to Human Intelligence, I think he could benefit from one of my favorites from another year, On Intelligence by Jeff Hawkins.

The Greatest Show on Earth by Richard Dawkins
Richard Dawkins comes through on the subject he knows best Evolution. He does a good job of showing how very much WE DO KNOW about evolution. He does spend some time kicking the sand castles of “Creationism” and the efforts to subvert our science education. Sometimes I can find his approach in this regard annoying and unnecessarily intolerant. But with this said, he does a wonderful job discussing what we do know, how we know it, and how the preponderance of evidence leaves no doubt in scientific terms of the validity of evolution.

Atlas Shrugged by Ayn Rand
At 63 hours this is a lot of listening. We started listening to this as a family during our trip to Idaho. We didn’t finish and so Samantha and I are listening to it on our drives to and from school. It’s been a lot of fun discussing the ideas with her!

Nullification by Thomas E. Woods
This was an odd but interesting book. He makes a case for States asserting pressure on the Federal Government by refusing to enforce unconstitutional Federal law. Who determines what is “unconstitutional”? State legislatures and petitions by the people. We can’t count on the Federal Supreme Court to protect us from Federal Tyranny. He demonstrates historical arguments by Jefferson and Madison for using this mechanism. Undoubtedly this is a messy way to deal with things but arguably the best way to bring some issues to a head.

Rounding out a number of Fiction novels a really enjoyed this year:

Eye of the Needle by Ken Follett - Classic Suspense.
The Reversal by Michael Connelly
Evidence by Jonathan Kellerman
61 Hours by Lee Child
R is for Ricochet by Sue Grafton
The Green Mile by Stephen King
Spin by Robert Charles Wilson

I always have books from Connelly, Kellerman, Child, Grafton, and King in my yearly Audible. Spin was really good but I’m undecided if Wilson’s other books are at the same quality.

Manipulating “Quoted Strings” in PowerShell with Regex MatchEvaluator

2010-12-31T19:16:06.791-05:00

I had an interesting problem where I needed to protect text within Quoted Strings from a series of Regex search and replace operations. Trying to write even simple regular expressions replace process that would exclude text in quotes was too painful for my understanding of Regex. I’m sure there are gurus who can throw that out but I’m not one of them.

While my job was more extensive than simply upper case, what if you wanted to change all characters in a string to upper case except for ones within double quotes? For example:

The “quick brown fox” jumped over the “lazy dog”
would become
THE “quick brown fox” JUMPED OVER THE “lazy dog”

There are number of quoted string regex expressions out there and I needed one that provided for escaped “ within the string that had a preceding \.

The following regex replace would replace quoted strings with the word STUFF

[regex]::Replace($value,'"([^"\\]*(\\.[^"\\]*)*)"', 'STUFF')

Not much help but that’s where the regex MatchEvaluator comes in to play. It’s a function that gets called for each match and the text it returns is what gets used. For example, what if I wanted to upper case only characters within double quotes? The following code would make quick work of it.

$value = 'The "quick brown fox" jumped over the "lazy dog"'

$QuotedTextMatchEvaluator = [System.Text.RegularExpressions.MatchEvaluator]{

$args[0].ToString().ToUpper()

}

[regex]::Replace($value,'"([^"\\]*(\\.[^"\\]*)*)"',$QuotedTextMatchEvaluator)

This produces
The “QUICK BROWN FOX” jumped over the “LAZY DOG”

Simple enough but as I said it was the opposite of what I needed and I was doing more interesting work than generating uppercase. My idea was to grab all of the quoted strings, save them in an array and then restore them when I was done. The save-quotedstrings function replaces each quoted string with a unique token then restore-quotedstrings replaces the token with the saved string. While context will dictate what is possible as a token, I chose to use an ASCII 1, a rarely used non-visible character followed by an incrementing number for each quoted string. save-quotestrings returns the tokenized string and the array of saved quoted strings. restore-quotedstrings takes a tokenized string and the saved string array and restores them.

function save-quotedstrings([string]$value)

{

$SavedStrings = @()

$QuotedTextMatchEvaluator = [System.Text.RegularExpressions.MatchEvaluator]{

$SavedStrings += $args[0].ToString()

[char]1 + ($SavedStrings.Count)

}

[regex]::Replace($value,'"([^"\\]*(\\.[^"\\]*)*)"',$QuotedTextMatchEvaluator),$SavedStrings

}

function restore-quotedstrings([string]$value,[array]$savedStrings)

{

(1..$savedStrings.Count) | %{$value = $value.Replace([char]1 + "$_",$savedStrings[$_-1])}

$value

}

$value = 'This "is \"a\" test" of a "quoted string" saver'

$value

$value,$savedStrings = save-quotedstrings $value

$value

$value = $value.ToUpper()

$value

$value = restore-quotedstrings $value $savedStrings

$value

The preceding code generates the following output.

This "is \"a\" test" of a "quoted string" saver
This _1 of a _2 saver
THIS _1 OF A _2 SAVER
THIS "is \"a\" test" OF A "quoted string" SAVER

Note: the _ is show instead of the non-displayable ASCII 1.

Long time noblog!

2010-12-08T20:36:34.7011582-05:00

Well it's been almost 3 years without a blog entry! I had actually forgotten all the passwords and had to start at the hosting, set my ftp password, get in at the file system, hack into the DasBlog config files before finally getting my login going.

This time I've got these things in my encrypted LockBox application. Even that doesn't leave me feeling safe. The App is a little clucky and people have talked about losing everything on an upgrade. This will be another 'todo'!

B

2008-03-21T21:15:26.6724863-04:00

Buck Hodges' VSTS 2005 and 2008: Building Database Projects with Team Build

While this is specifically about Team Build, it applies to any kind of automated build process using MSBuild. We're still using CCNet as our primary Build engine but Team Build is looking more appealing with 2008.

Organizing Audio Book MP3s with PowerShell

2008-03-09T22:27:18.891-04:00

In my previous blog entry, Easily setting Tags on Media Files using PowerShell, I described how to set the media tags used by common MP3 players.

The reason I had this need stemed from a frustration from RIPing Audio Books into MP3s. For example, let's say I'm compressing a 10 CD book. Even with "good" audio naming from Internet Naming sources, you get 10 different albums with numberd tracks from 1 to whatever. Sometimes the naming fixes this and sometimes it does a miserable job. Copying and renaming the files doesn't do the job. When you RIP the CD the encoder creates Meta Tags Used by MP3 players.

When your favorite tool is a hammer...

I didn't even look for a tool to solve this problem so if there is one... that's not really the point. I was curious if I could solve it very easily using Powershell. This is what I want:

Copy all files to a single directory
Name all files with some base name with a Zero padded count.
Provide for a flexible means for setting Tags on all Files. For example, Author
Set the Album Tag so all files will appear as a single album
Set Meta Track number to coorespond the the Count and Title to the Filename

When I RIP the CDs it easy to get them all under a single directory and organize the directories Alphabetically so the CDs are in order. The individually named where they also sort alphabetically. As such the following line will return all MP3s under a directory in the order they should be played:

dir-Recurse-Filter*.mp3

As such, I need a CmdLet where I can pipe these. This CmdLet will also take an Array parameter if that is your preference.

function Copy-NumberFile
( [ system.IO.FileInfo ] $file = $( Throw "File is required" )
, [ string ] $BaseName = $( Throw "BaseName is required" )
, $DestDir = $( Throw "DestDir is required" )
, [ int ] $Count = $( Throw "Count is required" )
, [ int ] $Digits = 1
, [ switch ] $Verbose
, [ switch ] $PassThru
)
{
$nbrStr = "{0:d$Digits}" -f $Count
$NewName = "$($BaseName)$($nbrStr)$($file.Extension)"
$NewFileName = [ System.IO.Path ]:: Combine ( $DestDir . FullName , $NewName )
if ( $Verbose )
{
Write-Host "Copy $($file.fullname) to $NewFileName"
}
   Copy-Item $file . FullName -Destination $NewFileName - PassThru : $PassThru
}

Function Organize-AudioBookFiles
( [ System.IO.DirectoryInfo ] $DestDir
, [ hashtable ] $Tags
, [ string ] $BaseName
, [ int ] $CountStart = 1
, $Digits =- 1
, [ array ] $Files )
{
begin
{
    [ array ] $fileList = $null
    function AddFile ( $FileToCheck )
    {
      if ( $fileToCheck -ne $null )
      {
        [ system.IO.FileInfo ] $file = $FileToCheck
        if ( ! $file . Exists ) { Throw "File does Not Exist" }
        $file
      }
    }

     if ( ! $DestDir . Exists )
    {
      $DestDir . Create ()
    }
     if (( dir $DestDir . FullName | Measure-Object ). Count -gt 0)
    {
      Throw "Destination Directory $($DestDir.FullName) is not empty"
     }
    foreach ( $file in $files )
    {
      $fileList += AddFile ( $file )
    }
}

process
{
    $fileList += AddFile ( $_ )
}

end
{
    $Count = $CountStart
   if ( $digits -lt 0)
    {
      [ int ] $Digits = [ System.Math ]:: Truncate (([ System.Math ]:: Log10 ( $fileList . Count + $Count ))) + 1
}
    foreach ( $file in $fileList )
    {
      $file = Copy-NumberFile -file $file -DestDir $DestDir -BaseName $BaseName `
        -Digits $digits -Count ( $Count ) -Verbose -PassThru
      $filename = $file . Name
      $Tags . Track = $Count
      $Tags . Title = $filename . Substring (0,( $filename . length - $file . extension . length ))
      SetMedia-Tags -file $file -Tags $Tags
      $Count ++
    }
}
}

I have a helper function "Copy-NumberFile". While I'm not sure if I'll ever need it in another operation, I can imagine it. It copies a file to a Destination Directory, renames it with a BaseName followed by a Number and preserving the extension. The number of Zero padded digits is specified in the $Digits parameter. The $PassThru allows the caller to get the FileInfo for the created file.

An example usage might look like:

$Tags= @{Artists="Book Author";Album="Book Title";Comment="This is a comment";Genres=@("Fiction")}
$files=dir-Recurse-Filter*.mp3
Organize-AudioBookFiles-Files$files-DestDir"C:\temp\Book"-BaseName"BookName "-Tags$Tags

Easily setting Tags on Media Files using PowerShell

2008-03-09T21:12:26.328-04:00

This weekend I found the need to set the Media Meta Tags in MP3 files I have RIPed. I found this Huddled Masses article for using the taglib-sharp library. I find Hashtables as a convenient machine for passing Pthese kinds of adhoc Name\Value pairs.

[

void ] [ Reflection.Assembly ]:: LoadFile ( ".\taglib-sharp.dll" )

function

SetMedia-Tags
( [ System.IO.FileInfo ] $File = $( Throw "File is required" )
, [ hashtable ] $Tags = $( Throw "Tags are required" ))
{
$media = [ TagLib.File ]:: Create ( $file . FullName )
foreach ( $tag in $Tags . keys )
{
$media . Tag . $tag = $Tags [ $tag ]
}
$media . Save ()
}

Example Usage:

$Tags

= @{ Artists = "Max Headgroom" ;Album = "Smoke" ;Comment = "This is a comment" ;Genres = @( "Crazy" )}
SetMedia-Tags -File ".\file1.mp3" -Tags $Tags

I used this code in a more specific project for organizing Audio Book MP3s I'll describe in a subsequent post.

Invoking NAnt from Powershell

2008-03-07T18:26:48.827-05:00

One of the interesting things about having a blog is seeing what people are searching for when they navigate to an entry. On at least a dozen occasions I've seen searches where people were obviously trying to invoke NAnt from PowerShell. Because I've talked about both NAnt and PowerShell without speaking to this subject, they have been disappointed in what they've found in my blogs. Indeed, when I've performed my own searches, I've noticed there isn't a lot of useful info on doing this subject. Especially at detecting an error in the NAnt script.

This isn't the most comprehensive script but it does the basics:

function

Invoke-NAnt ( $NantFile , $target ,[ hashtable ] $Properties )
{
$sb=New-Object "System.Text.StringBuilder"
if ($properties-ne$null)
{
    foreach ($keyin$Properties.Keys)
    {
      [void] $sb.Append( '"'+"-D:$key=$($Properties.$key)"+'" ' )
    }
  }

  nant"-f:$NantFile"$target$sb.ToString()

if (-not$?)
{
    Throw "Nant Failed"
}
}

Example Usage:

Invoke-NAnt

Test.build "TestTarget" @{ Test1 = "Value1" ;Test2 = "Value2" }

Test.Build contains:

project >
< target name = " TestTarget " >
< echo message = " Test1=${Test1} " />
< echo message = " Test2=${Test2} " />
< fail message = " This is a failure " />
target >
project >

Output looks like:

NAnt 0.85 (Build 0.85.2478.0; release; 10/14/2006)
Copyright (C) 2001-2006 Gerry Shaw
http://nant.sourceforge.net

Buildfile: file:///C:/Projects/PSNant/Test.build
Target framework: Microsoft .NET Framework 2.0
Target(s) specified: TestTarget

TestTarget:

     [echo] Test1=Value1
     [echo] Test2=Value2

BUILD FAILED

C:\Projects\PSNant\Test.build(6,6):
This is a failure

Total time: 0 seconds.

Nant Failed
At C:\Projects\PSNant\InvokeNant.PS1:19 char:10
+     Throw <<<< "Nant Failed"

This particular script is designed to fail with the 'fail task'. This is because I was having trouble detecting errors.

if (-not$?)
{
Throw "Nant Failed"
}

The $? variable is set to $true if the previous instruction succeeded. As of yet, I'm not getting the actual failure message. If someone can help with that, I'd appreciate it.

Other usage comments:

The $properties parameter takes a hash table that gets marshaled into -D:= line arguments. I find the syntax of @{Test1="Value1";Test2="Value2"} to be more natural for PowerShell.

This function will return an array of text lines which are the output from NAnt. If you don't want them to pipe out you'll need to assign it to a variable or [void] it.

$NantOutput

= Invoke-NAnt Test.build "TestTarget" @{ Test1 = "Value1" ;Test2 = "Value2" }

Finally: Obviously this needs to be dressed out a little more for supporting some useful parameters to NAnt like Logger and Default Framework.

Running Linux on Virtual PC

2008-02-23T20:33:58.24-05:00

Good writeup on installing Ubuntu 7.10 on Virtual PC. However, it hung for me right after the first screen with two different ISO downloads. I was trying this at home on my AMD Vista Laptop. Some comments on the page makes me suspicious that I'll need use my Virtual Server at work.

Update:

With an RDP connection to an XP system at work I was able to get the Ubuntu to install. I'll conclude, for now, there is some issue with VPC on Vista.

The mouse continued to be flaky but it could be the system within system within system connection I was using. I'm on a Vista laptop with a touchpad, running an XP VPC with VPN RDP connection to an XP System running the Ubuntu VPC! Now why can't my mouse work?! :)

I guess on Monday I'll see how well the mouse works when I can get direct access to the VPC. Next hurdle... get it on the network. Then to see if I can Admin the thing through Powershell!

Controlling Linux from PowerShell?

2008-02-23T00:11:47.897-05:00

I'm in the initial stages of attempting to control Linux servers from Windows using PowerShell.

The obvious path is using SSH. The question is how. Unfortunately with all the buzz around PowerShell Remoting, what I'm finding is a lot of the reverse... accessing PowerShell through SSH. The reciprocity of this may make the reverse true but I haven't found the confirmation link yet.

The long way around the block might be through Cygwin and Putty. The link is a little old but it shows a way. I'm hoping for a direct path from PowerShell so I can minimize installation dependencies.

Update:

NetCmdlets is the "almost" direct path. It looks good but too pricy for the way I want use it. Besides, it's "just" a wrapper for rsh.exe. Looks like I'll be attempting my own wrapper. Anyone else try to do this?

Analyze Hard Drive Extensions with PowerShell

2008-02-17T19:57:25.296-05:00

The other day I was given a hard drive and asked to analyze what was on it. While it was easy to determine it had over 300,000 files and about 10 Gigs I didn’t want to navigate through the whole thing looking in the hundreds of folders. I figured a good thing to know was the number of files and size by extension.

Powershell to the rescue. After several iterations of various techniques I came up with a CmdLet allowing me to measure any kind of object. You can specify which property to use as the Group and for measurement. I’m not sure what else I’ll use it for, but I love making things generic.

function MeasureGroup-Object

( [string]$group=$(Throw "Group Name is Required")

, [string]$property=$(Throw "Property Name is Required")

, $items

)

{

begin

{

function processItem($item)

{

$key = $item.$group

if ($Aggregate.$key -eq $null)

{

$Aggregate.$key = @{Count=0;Sum=0}

}

$Aggregate.$key.Count += 1

$Aggregate.$key.Sum += $item.$property

}

# Hash table to collect stats

$Aggregate = @{}

if ($items -ne $null)

{

foreach ($item in $items)

{

processItem $item

}

process

{

if ($_ -ne $null)

{

processItem $_

}

end

{

function AddProperty ($object,$name,$value)

{

$member = new-object management.automation.PSNoteProperty $name,$value

$object.psobject.members.Add($member)

}

foreach ($key in $Aggregate.Keys)

{

$obj = new-object management.automation.psobject

AddProperty $obj $group $key

AddProperty $obj Count $Aggregate.$key.Count

AddProperty $obj Sum $Aggregate.$key.Sum

$obj

}

So let’s put it to work. First you have to collect the objects you want to measure.

$files = Get-ChildItem -Recurse | where {$_ -is [System.IO.FileInfo]}

This will recursively collect all the files under the current directory. It helps to filter out the Directories. Because they don’t have Extensions, they would end up inflating the stats for files without extensions.

Now to use the MeasureGroup-Object.

$stats = MeasureGroup-Object Extension Length $files

The $stats variable will contain an array with an entry for each extension type. Each entry will have an Extension, Count and Sum value.

The following will display the results but not in any particular order.

$stats

This will be more interesting.

# Get Top 5 file types by count

$stats | Sort-Object Count -Descending | Select-Object -First 5

Extension Count Sum

--------- ----- ---

.cs 842 3018481

.hxs 765 980371275

.cab 756 1801724080

.sql 538 6734980

.dll 367 79635976

These are also interesting views.

# Get Top 5 file types by total Length

$stats | Sort-Object Sum -Descending | Select-Object -First 5

# Display all Extensions

$stats | Sort-Object Extension

Some comments about the implementation.

The End processing loops through the $Aggregate results and builds PSObjects with Note values. The PSObjects play nice with the Sort, Select and default display.

Powershell Pipeline CmdLet Template

2008-02-17T18:26:38-05:00

This is a useful template for starting a CmdLet that needs to work in a PipeLine or by passing parameters.

Processing is implemented in the processItem sub-function. All the “–ne $null” conditions handle the differences between pipeline and parameter invocation.

function Test-PipelineOrParm ($parm)

{

begin

{

function processItem($item)

{

# Implement processing in this function

"processItem $item"

}

if ($parm -ne $null)

{

foreach ($item in $parm)

{

"begin $(processItem $item)"

}

process

{

if ($_ -ne $null)

{

"process $(processItem $_)"

}

end

{

Write-Host "Done"

}

These two examples demonstrate calling the template.

Write-Host "Test Pipeline processing"

Get-ChildItem | Test-PipelineOrParm

Write-Host "Test Parm processing"

Test-PipelineOrParm $(Get-ChildItem)

Object Oriented Scripting in Powershell

2008-02-17T15:19:52-05:00

The past few weeks I’ve been working on a Powershell OO scripting framework. I figure I better go ahead and publish it because I could keep tinkering on it for a long time. I suspect it’s not done and even has a bug or two but it’s in decent shape. While this is not “real” Object Oriented it does support:

· Polymorphism

· Encapsulation

· Constructors with parameters

· Notes – read-write variables

· Methods – scriptblocks

· Properties with Get scriptblocks and optional Set scriptblocks

· Static and Private Notes and Methods

The New-PSClass cmdlet takes a script which acts as Class Definition. Keywords note, method, property and constructor are local functions in New-PSClass and act as Class Definition by attaching objects to a PSClass Object returned by the CmdLet.

The PSClass has a New() method. Parameters to New are passed to the constructor script. Due to a bug in V1.0 of PowerShell, the Param statement does not work in the scriptblocks in PSClass. While I have not tried it yet, I have good reason to believe that it will work in V2.0. While it’s not as nice, the $Args variable works fine.

Instead of trying to describe all the syntax as small points in the blog entry, I’ll present an example Animal Class with a Dog and Bird Classes that inherit from it. While looking through it take note of:

· Private Notes use a –private switch. Within the class, scripts access them through a $private variable. Encapsulatioen isolates them from inherited classes and easy public access.

· Static Notes and Methods are attached to the PSClass object. This example shows a Static Note accessed in the Constructors. This may seem non-intuitive considering the Class Object used in the Constructor is not created until New-PSClass is completed. This is because the constructor script is not executed until an action Object is created using the New() method.

· While not demonstrated, private methods are supported and attached to the $private variable available in script execution.

· Note the use the –override switch on the ToString() method on the Dog Class. It can call methods on the base class through Invoke-BaseClassMethod

· Base function in constructors to call inherited constructors

$AnimalClass = New-PSClass Animal {

note -static ObjectCount 0

method -static DisplayObjectCount {

"$($this.ClassName) has $($this.ObjectCount) instances"

}

note -private Name

note -private Legs

constructor {

$private.Name = $Args[0]

$private.Legs = $Args[1]

$AnimalClass.ObjectCount += 1

}

property Name {

$private.Name

} -set {

Write-Host "Renaming $($this.Class.ClassName) '$($private.Name)' to '$($Args[0])'"

$private.Name = $Args[0]

}

property Legs {

$private.Legs

}

method -override ToString {

"A $($this.Class.ClassName) named $($this.name) with $($this.Legs) Legs"

}

method Speak {

Throw "not implemented"

}

$DogClass = New-PSClass -inherit $AnimalClass Dog {

note -static ObjectCount 0

method -static DisplayObjectCount {

"$($this.ClassName) has $($this.ObjectCount) instances"

}

constructor {

Base $Args[0] 4

$DogClass.ObjectCount += 1

}

method -override ToString {

"$(Invoke-BaseClassMethod 'ToString') with extra"

}

method -override Speak {

"Arf"

}

$BirdClass = New-PSClass -inherit $AnimalClass Bird {

note -static ObjectCount 0

method -static DisplayObjectCount {

"$($this.ClassName) has $($this.ObjectCount) instances"

}

constructor {

Base $Args[0] 2

$BirdClass.ObjectCount += 1

}

method -override Speak {

"Squawk"

}

$Dog = $DogClass.New("Bowser")

$Dog.ToString()

$Dog.Name = "Duke"

$Dog.ToString()

$Dog.Speak()

$Bird = $BirdClass.New("Tweedy")

$Bird.ToString()

$Bird.Speak()

$DogClass.DisplayObjectCount()

$BirdClass.DisplayObjectCount()

$AnimalClass.DisplayObjectCount()

Output:

A Dog named Bowser with 4 Legs with extra

Renaming Dog 'Bowser' to 'Duke'

A Dog named Duke with 4 Legs with extra

Arf

A Bird named Tweedy with 2 Legs

Squawk

Dog has 1 instances

Bird has 1 instances

Animal has 2 instances

The cool thing about the implementation is it’s all in PowerShell. It’s a big chunk of code and I’m sure it’s not its final version, but it has a lot of cool techniques and some that should be fixed up. Also, I’ve been working on an XMS Serialization, Attribute support, and the ability to attach PSClass objects to any PowerShell object.

These PowerShell Scripts are in the attached zip file.

# ===================================================================================

# New-PSClass

# Object Oriented Scripting in Powershell

# http://www.cashfoley.com/

# ===================================================================================

# Inspired by Bruce Payette's "Windows PowerShell in Action"

# Chapter 8 Script to add a CustomClass "keyword" to PowerShell

# http://manning.com/payette/

# ===================================================================================

function New-PSClass

( [string] $ClassName = { Throw "ClassName required for New-PSClass"}

, [scriptblock] $definition = { Throw "Definition required for New-PSClass"}

, $Inherit

)

{

#======================================================================

# These Subfunctions are used in Class Definition Scripts

#======================================================================

# - - - - - - - - - - - - - - - - - - - - - - - -

# Subfunction: constructor

# Assigns Constructor script to Class

# - - - - - - - - - - - - - - - - - - - - - - - -

function constructor ( [scriptblock] $script=$(Throw "Script is required for 'constructor'"))

{

if ($class.ConstructorScript)

{

Throw "Only one Constructor is allowed"

}

$class.ConstructorScript = $script

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Subfunction: note

# Adds Notes record to class if non-static

# - - - - - - - - - - - - - - - - - - - - - - - -

function note

{

param ( [string]$name={Throw "Note Name is Required"}

, $value=""

, [switch] $private

, [switch] $static

)

if ($static)

{

if ($private)

{

Throw "Private Static Notes are not supported"

}

Attach-PSNote $class $name $value

}

else

{

$class.Notes += @{Name=$name;DefaultValue=$value;Private=$private}

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Subfunction: method

# Add a method script to Class definition or

# attaches it to the Class if it is static

# - - - - - - - - - - - - - - - - - - - - - - - -

function method ([string]$name=$(Throw "Name is required for 'method'"), [scriptblock] $script=$(Throw "Script is required for 'method'"), [switch] $static, [switch]$private, [switch]$override )

{

if ($static)

{

if ($private)

{

Throw "Private Static Methods not supported"

}

Attach-PSScriptMethod $class $name $script

}

else

{

$class.Methods[$name] = @{Name=$name;Script=$script;Private=$private;Override=$override}

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Subfunction: property

# Add a property to Class definition or

# attaches it to the Class if it is static

# - - - - - - - - - - - - - - - - - - - - - - - -

function property ([string]$name, [scriptblock] $get=$(Throw "Get Script is required for 'property'"), [scriptblock] $set, [switch] $static, [switch]$private, [switch]$override )

{

if ($static)

{

if ($private)

{

Throw "Private Static Properties not supported"

}

Attach-PSProperty $class $name $get $set

}

else

{

$class.Properties[$name] = @{Name=$name;GetScript=$get;SetScript=$set;Private=$private;Override=$override}

}

$class = new-object Management.Automation.PSObject

# Class Internals

Attach-PSNote $class ClassName $ClassName

Attach-PSNote $class Notes @()

Attach-PSNote $class Methods @{}

Attach-PSNote $class Properties @{}

Attach-PSNote $class BaseClass $Inherit

Attach-PSNote $class ConstructorScript

Attach-PSNote $class PrivateName "__$($ClassName)_Private"

Attach-PSScriptMethod $class New {

$instance = new-object Management.Automation.PSObject

$this.AttachObject( $instance )

$this.Initialize( $instance, $Args )

$instance

}

Attach-PSScriptMethod $class Initialize {

if ($this.ConstructorScript -ne $null)

{

__PSClass-Initialize $Args[0] $Args[1]

}

Attach-PSScriptMethod $class AttachObject {

__PSClass-AttachObject $Args[0]

}

Attach-PSScriptMethod $class __LookupClassObject {

__PSClass-LookupClassObject $Args[0] $Args[1]

}

Attach-PSScriptMethod $class InvokeMethod {

__PSClass-InvokeMethod $Args[0] $Args[1] $Args[2]

}

Attach-PSScriptMethod $class InvokeProperty {

__PSClass-InvokePropertyMethod $Args[0] $Args[1] $Args[2] $Args[3]

}

# At last, execute definition script

&$definition

# return constructed class

$class

}

# ===================================================================================

# These helper Cmdlets should only be called by New-PSClass. They exist to reduce

# the amount of code attached to each PSClass object. They rely on context

# variables not passed as parameters.

# ===================================================================================

# __PSClass-Initialize

# Invokes Constructor Script and provides helper Base function to facilitate

# Inherited Constructors

# ===================================================================================

function __PSClass-Initialize ($instance, $params)

{

function Base

{

if ($this.Class.BaseClass -eq $null)

{

Throw "No BaseClass implemented for $($this.Class.ClassName)"

}

$this.Class.BaseClass.Initialize($this,$Args)

}

trap {

$errorMsg = $_.Exception.Message + $_.Exception.ErrorRecord.InvocationInfo.PositionMessage

Throw $errorMsg

$_.ErrorDetails = $_.Exception.ErrorRecord.InvocationInfo.PositionMessage

}

$constructor = $this.ConstructorScript

$private = $Instance.($this.privateName)

$this = $instance

$constructor.InvokeReturnAsIs( $params )

}

# ===================================================================================

# __PSClass-AttachObject

# Attaches Notes, Methods, and Properties to Instance Object

# ===================================================================================

function __PSClass-AttachObject ($instance)

{

function AssurePrivate

{

if ($instance.($this.privateName) -eq $null)

{

Attach-PSNote $instance ($this.privateName) (new-object Management.Automation.PSObject)

Attach-PSNote $instance.($this.privateName) __Parent $instance

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Attach BaseClass

# - - - - - - - - - - - - - - - - - - - - - - - -

if ($this.BaseClass -ne $null)

{

$this.BaseClass.AttachObject($instance)

}

Attach-PSNote $instance Class $this

# - - - - - - - - - - - - - - - - - - - - - - - -

# Attach Notes

# - - - - - - - - - - - - - - - - - - - - - - - -

foreach ($note in $this.Notes)

{

if ($note.private)

{

AssurePrivate

Attach-PSNote $instance.($this.privateName) $note.Name $note.DefaultValue

}

else

{

Attach-PSNote $instance $note.Name $note.DefaultValue

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Attach Methods

# - - - - - - - - - - - - - - - - - - - - - - - -

foreach ($key in $this.Methods.keys)

{

$method = $this.Methods[$key]

$targetObject = $instance

# Private Methods are attached to the Private Object.

# However, when the script gets invoked, $this needs to be

# pointing to the instance object. $ObjectString resolves

# this for InvokeMethod

if ($method.private)

{

AssurePrivate

$targetObject = $instance.($this.privateName)

$ObjectString = '$this.__Parent'

}

else

{

$targetObject = $instance

$ObjectString = '$this'

}

# The actual script is not attached to the object. The Script attached to Object calls

# InvokeMethod on the Class. It looks up the script and executes it

$instanceScriptText = $ObjectString + '.Class.InvokeMethod( "' + $method.name + '", ' + $ObjectString + ', $Args )'

$instanceScript = $ExecutionContext.InvokeCommand.NewScriptBlock( $instanceScriptText )

Attach-PSScriptMethod $targetObject $method.Name $instanceScript -override:$method.override

}

# - - - - - - - - - - - - - - - - - - - - - - - -

# Attach Properties

# - - - - - - - - - - - - - - - - - - - - - - - -

foreach ($key in $this.Properties.keys)

{

$Property = $this.Properties[$key]

$targetObject = $instance

# Private Properties are attached to the Private Object.

# However, when the script gets invoked, $this needs to be

# pointing to the instance object. $ObjectString resolves

# this for InvokeMethod

if ($Property.private)

{

AssurePrivate

$targetObject = $instance.($this.privateName)

$ObjectString = '$this.__Parent'

}

else

{

$targetObject = $instance

$ObjectString = '$this'

}

# The actual script is not attached to the object. The Script attached to Object calls

# InvokeMethod on the Class. It looks up the script and executes it

$instanceScriptText = $ObjectString + '.Class.InvokeProperty( "GET", "' + $Property.name + '", ' + $ObjectString + ', $Args )'

$getScript = $ExecutionContext.InvokeCommand.NewScriptBlock( $instanceScriptText )

if ($Property.SetScript -ne $null)

{

$instanceScriptText = $ObjectString + '.Class.InvokeProperty( "SET", "' + $Property.name + '", ' + $ObjectString + ', $Args )'

$setScript = $ExecutionContext.InvokeCommand.NewScriptBlock( $instanceScriptText )

}

else

{

$setScript = $null

}

Attach-PSProperty $targetObject $Property.Name $getScript $setScript -override:$Property.override

}

# ===================================================================================

# __PSClass-LookupClassObject

# intended to look up methods and property objects on the Class. However,

# it can be used to look up any Hash Table entry on the class.

# if the object is not found on the instance class, it searches all Base Classes

# $ObjectType is the HashTable Member

# $ObjectName is the HashTable Key

# it returns the Class and Hashtable entry it was found in

# ===================================================================================

function __PSClass-LookupClassObject ($ObjectType, $ObjectName)

{

$object = $this.$ObjectType[$ObjectName]

if ($object -ne $null)

{

$this

$object

}

else

{

if ($this.BaseClass -ne $null)

{

$this.BaseClass.__LookupClassObject($ObjectType, $ObjectName)

}

# ===================================================================================

# __PSClass-InvokeScript

# Used to invoke Method and Property scripts

# It adds an error handler so Script Info can be seen in the error

# It marshals $this and $private variables for the context of the script

# It provides a helper Invoke-BaseClassMethod for invoking base class methods

# ===================================================================================

function __PSClass-InvokeScript ($class, $script, $object, $parms )

{

function Invoke-BaseClassMethod ($methodName, $parms)

{

if ($this.Class.BaseClass -eq $null)

{

Throw "$($this.Class.ClassName) does not have a BaseClass"

}

$class,$method = $this.Class.BaseClass.__LookupClassObject('Methods', $MethodName)

if ($method -eq $null)

{

Throw "Method $MethodName not defined for $className"

}

__PSClass-InvokeScript $class $method.Script $this $parms

}

trap {

$errorMsg = $_.Exception.Message + $_.Exception.ErrorRecord.InvocationInfo.PositionMessage

Throw $errorMsg

$_.ErrorDetails = $_.Exception.ErrorRecord.InvocationInfo.PositionMessage

}

$this = $object

$private = $this.($Class.privateName)

$script.InvokeReturnAsIs( $parms )

}

# ===================================================================================

# __PSClass-InvokeMethod

# Script called by methods attached to instances. Looks up Method Script

# in instance class or in inherited class

# ===================================================================================

function __PSClass-InvokeMethod($MethodName, $instance, $parms)

{

$class,$method = $this.__LookupClassObject('Methods', $MethodName)

if ($method -eq $null)

{

Throw "Method $MethodName not defined for $($this.ClassName)"

}

__PSClass-InvokeScript $class $method.Script $instance $parms

}

# ===================================================================================

# __PSClass-InvokePropertyMethod

# Script called by property scripts attached to instances. Looks up property Script

# in instance class or in inherited class

# ===================================================================================

function __PSClass-InvokePropertyMethod ($PropertyType, $PropertyName, $instance, $parms)

{

$class,$property = $this.__LookupClassObject('Properties', $PropertyName)

if ($property -eq $null)

{

Throw "Property $PropertyName not defined for $($this.ClassName)"

}

if ($PropertyType -eq "GET")

{

__PSClass-InvokeScript $class $property.GetScript $instance $parms

}

else

{

__PSClass-InvokeScript $class $property.SetScript $instance $parms

}

# ===================================================================================

function Attach-PSNote

{

param ( [PSObject]$object=$(Throw "Object is required")

, [string]$name=$(Throw "Note Name is Required")

, $value

)

if (! $object.psobject.members[$name])

{

$member = new-object management.automation.PSNoteProperty `

$name,$value

$object.psobject.members.Add($member)

}

else

{

if($value)

{

$object.$name = $value

}

# ===================================================================================

function Attach-PSScriptMethod

{

param ( [PSObject]$object=$(Throw "Object is required")

, [string]$name=$(Throw "Method Name is Required")

, [scriptblock] $script

, [switch] $override

)

$member = new-object management.automation.PSScriptMethod `

$name,$script

if ($object.psobject.members[$name] -ne $null)

{

if ($override)

{

$object.psobject.members.Remove($name)

}

else

{

Throw "Method '$name' already exists with out 'override'"

}

$object.psobject.members.Add($member)

}

# ===================================================================================

function Attach-PSProperty

{

param ( [PSObject]$object=$(Throw "Object is required")

, [string]$name=$(Throw "Method Name is Required")

, [scriptblock] $get=$(Throw "get script is required")

, [scriptblock] $set

, [switch] $override

)

if ($set)

{

$scriptProperty = new-object management.automation.PsScriptProperty `

$name,$get,$set

}

else

{

$scriptProperty = new-object management.automation.PsScriptProperty `

$name,$get

}

if ( $object.psobject.properties[$name] -and $override)

{

$object.psobject.properties.Remove($name)

}

$object.psobject.properties.add($scriptProperty)

}

PSClass.zip (4.24 KB)