优雅的 PowerShell 圣诞节

又到了一年中使用 PowerShell 享受假期乐趣的时候了。今年我想送你一份优雅的礼物。或者更准确地说，是一个基于类的 PowerShell 玩具。 PowerShell 5.0 中引入了类，主要考虑到 DSC 资源，但您可以将类用于各种用途。

简单来说，类是某种类型对象的定义。在 PowerShell 中，您现在可以在简单的 PowerShell 脚本文件中定义类。基本轮廓如下所示：

Class theClassName {

#define properties

#define methods (optional)

#define constructors (optional

}

构造函数是可以创建类或对象实例的代码块。它是完全可选的，因为您可以使用以下语句之一创建类的实例：

[theClassname]::New()
New-Object theClassname

但也许我应该让你打开我的班级礼物。

#requires -version 5.0

<#
ChristmasClass.ps1
A demo PowerShell class
#>

Enum ListStatus {
    Naughty
    Nice
}

Enum Present {
    Socks
    Barbie
    Elmo
    XBox
    GIJoe
    Underwear
    HotWheels
    EZBakeOven
    Walkman
    PS4
    Pajamas
    Stratego
    GinzuKnives
    ChiaPet
    Tie
    Mittens
    Bicycle
    Pony
    Battleship
    CabbagePatchDoll
}

Class myChristmas {

#class properties
[string]$Greeting
[string]$ElfName
[ListStatus]$List
[int]$DaysRemaining
[string]$CountDown

#class methods
[string]GetGreeting() {
  $texts = @("Merry Christmas","Happy Holidays","HO-HO-HO","Vrolijk Kerstfeest",
  "Joyeux Noël","Frohe Weihnachten","Hyvää Joulua","Glædelig Jul","Kala Christouyenna",
  "Mele Kalikimaka","Buon Natale","Merry Xmas","Merry Christmas & A Happy New Year",
  "Meri Kuri","God Jul","Nollaig Chridheil","Feliz Navidad",
  "Schöni Wiehnachte","Mutlu Noeller","Nadolig Llawen","toDwI'ma' qoS yItIvqu'"
   )
  $text = $texts | Get-Random
  return $text
}

[string]GetElfName() {

    $first = "Toby","Bernard","Princess","Harvey","Chuck","Doris","Elsa",
    "Snookums","Honey","Norm","Coco","Sven","Inga","Boris",
    "Benedict","Sunshine","Kiki","Nutmeg","Humperdink","Jack",
    "Bertha","Matilda","Clarice","Dwight","Hermey","Rupert","Lady",
    "Izzy"

    $mod = "Ginger","Glitter","Frosty","Sugar","Sour","Pepper",
    "Minty","Crazy","Spicy","Pickle","Twinkle","Sparkle","Disco","Red",
    "Green","Little","Big","Tiny","Glow","Shimmer","Dazzle","Winter","Jingle",
    "Puffy","Fluffy","Saucy","Crinkle"
    
    $last = "pants","toes","bottom","beard","nose","puss","lips",
    "ears","socks","stockings","belly","cheeks","bells","chin",
    "mctush","sticks","fish","whisker","boots","slippers","knicker",
    "knocker"

    $name = "{0} {1}{2}" -f (Get-Random $first),(Get-Random $mod),(Get-Random $last)
    return $name
}

[void]Refresh() {
 #calculate christmas for the current year that should be culture aware
 $Christmas = [datetime]::new( (Get-Date).Year,12,25)
 $span = $Christmas - (Get-Date)
 $this.DaysRemaining = $span.totalDays
 #strip off milliseconds
 $timestring = $span.ToString()
 $this.CountDown = $timestring.Substring(0,$timestring.LastIndexOf("."))
 
 $this.Greeting = $this.GetGreeting()
}

#overloaded method
[Present]GetPresent() {
  $presents = [enum]::GetNames([present]) | Get-Random
  return $presents
}

[Present[]]GetPresent([int]$Count) {
  $presents = [enum]::GetNames([present]) | Get-Random -count $Count
  return $presents
}

[void]Play() {
  #The first number is the reciprocal of the duration and the rest is the 
#note and octave (which we use for getting the frequency).  
#For example, 4A4 is a quarter A note

#first verse only
$notes =  write 4A4 4A4 2A4        4A4 4A4 2A4        4A4 4C4 4F3 8G3             1A4 `
  4Bb4 4Bb4 4Bb4 8Bb4     4Bb4 4A4 4A4 8A4 8A4    4A4 4G3 4G3 4A4    2G3 2C4 `
  4A4 4A4 2A4       4A4 4A4 2A4    4A4 4C4 4F3 4G3     1A4        4Bb4 4Bb4 4Bb4 4Bb4 `
  4Bb4 4A4 4A4 8A4 8A4    4C4 4C4 4Bb4 4G3     1F3  

function Play([int] $freq, [int] $duration)
{
  [console]::Beep($freq, $duration);
}

 
#
# Note is given by fn=f0 * (a)^n
# a is the twelth root of 2
# n is the number of half steps from f0, positive or negative.
# f0 used here is A4 at 440 Hz
#
$f0 = 440;
$a = [math]::pow(2,(1/12)); # Twelth root of 2
function GetNoteFreq([string]$note)
{
  # n is the number of half steps from the fixed note.
  $note -match '([A-G#]{1,2})(\d+)' | out-null
  $octave = ([int] $matches[2]) - 4;
  $n = $octave * 12 + ( GetHalfStepsFromA $matches[1] );
  $freq = $f0 * [math]::Pow($a, $n);

  return $freq;
}

 
function GetHalfStepsFromA([string] $note)
{
  switch($note)
  {
    'A'  { 0 }
    'A#' { 1 }
    'Bb' { 1 }
    'B'  { 2 }
    'C'  { 3 }
    'C#' { 4 }
    'Db' { 4 }
    'D'  { 5 }
    'D#' { 6 }
    'Eb' { 6 }
    'E'  { 7 }
    'F'  { 8 }
    'F#' { 9 }
    'Gb' { 9 }
    'G'  { 10 }
    'G#' { 11 }
    'Ab' { 11 }
  }
}


$StandardDuration = 1000;
foreach($note in $notes)
{

  $note -match '(\d)(.+)' | out-null
  $duration = $StandardDuration / ([int] $matches[1]);
  $playNote = $matches[2];
  $freq = GetNoteFreq $playNote;

  #write-host $playNote $freq $duration;
 Play $freq $duration
  start-sleep -milli 50
}

}

[void]Show() {
  cls

$Msg1 =
@"
.:*~*:._.:*~*:._.:*~*:._.:*~*:._.:*~*:._.:*~*:.
.     *                                       .
.    /.\        Merry Christmas               .
.   /..'\            from all of us           .
.   /'.'\                in PowerShell        .
.  /.''.'\                                    .
.  /.'.'.\                                    .
. /'.''.'.\                                   .
. ^^^[_]^^^                                   .
.                                             .
.                                             .
.                                          .
.:*~*:._.:*~*:._.:*~*:._.:*~*:._.:*~*:._.:*~*:.
"@


$Msg2 =
@"
                    _...
              o_.-"`    `\
       .--.  _ `'-._.-'""-;     _
     .'    \`_\_  {_.-a"a-}  _ / \
   _/     .-'  '. {c-._o_.){\|`  |
  (@`-._ /       \{    ^  } \ _/
   `~\  '-._      /'.     }  \}  .-.
     |>:<   '-.__/   '._,} \_/  / ())  
     |     >:<   `'---. ____'-.|(`"`
     \            >:<  \_\_\ | ;
      \                 \-{}-\/  \
       \                 '._\'   /)
        '.                       /(
          `-._ _____ _ _____ __.'\ \
            / \     / \     / \   \ \ 
         _.'/^\'._.'/^\'._.'/^\'.__) \
     ,=='  `---`   '---'   '---'      )
     `"""""""""""""""""""""""""""""""`
"@

$msg3 = 
@"
               ___
             /`   `'.
            /   _..---;
            |  /__..._/  .--.-.
            |.'  e e | ___\_|/____
           (_)'--.o.--|    | |    |
          .-( `-' = `-|____| |____|
         /  (         |____   ____|
         |   (        |_   | |  __|
         |    '-.--';/'/__ | | (  `|
         |      '.   \    )"";--`\ /
         \        ;   |--'    `;.-'
         |`-.__ ..-'--'`;..--'`
"@

$msg4 = 
@"
           *             ,
                       _/^\_
                      <     >
     *                 /.-.\         *
              *        `/&\`                   *
                      ,@.*;@,
                     /_o.I %_\    *
        *           (`'--:o(_@;
                   /`;--.,__ `')             *
                  ;@`o % O,*`'`&\ 
            *    (`'--)_@ ;o %'()\      *
                 /`;--._`''--._O'@;
                /&*,()~o`;-.,_ `""`)
     *          /`,@ ;+& () o*`;-';\
               (`""--.,_0 +% @' &()\
               /-.,_    ``''--....-'`)  *
          *    /@%;o`:;'--,.__   __.'\
              ;*,&(); @ % &^;~`"`o;@();         *
              /(); o^~; & ().o@*&`;&%O\
              `"="==""==,,,.,="=="==="`
           __.----.(\-''#####---...___...-----._
         '`         \)_`"""""`
                 .--' ')
               o(  )_-\
                 `"""` `
 
"@

$msg5 =
@"
                        .--------.
   *               .    |________|        .          *
                        |      __|/\
             *        .-'======\_\o/.
                     /___________<>__\
               ||||||  /  (o) (o)  \
               |||||| |   _  O  _   |          .
     .         |||||| |  (_)   (_)  |
               ||||||  \   '---'   /    *
               \====/   [~~~~~~~~~]
                \//  _/~||~`|~~~~~\_
                _||-'`/  ||  |      \`'-._       *
        *    .-` )|  ;   ||  |)      ;    '. 
            /    `--.|   ||  |       |      `\
           |         \   |||||)      |-,      \         .
            \       .;       _       ; |_,    |
             `'''||` ,\     (_)     /,    `.__/
                 ||.`  '.         .'  `.             *
      *          ||       ` ' ' `       \
                 ||                      ;
   .          *  ||                      |    .
                 ||                      |              *
                 ||                      |
 .__.-""-.__.-"""||                      ;.-"""-.__.-""-.__.
                 ||                     /
                 ||'.                 .'
                 ||  '-._  _ _  _ _.-'
                `""`       
"@
$msg6 =
@"
                                  _
                               .-(_)
                              / _/
                           .-'   \
                          /       '.
                        ,-~--~-~-~-~-,
                       {__.._...__..._}             ,888,
       ,888,          /\##"  6  6  "##/\          ,88' `88,
     ,88' '88,__     |(\`    (__)    `/)|     __,88'     `88
    ,88'   .8(_ \_____\_    '----'    _/_____/ _)8.       8'
    88    (___)\ \      '-.__    __.-'      / /(___)
    88    (___)88 |          '--'          | 88(___)
    8'      (__)88,___/                \___,88(__)
              __`88,_/__________________\_,88`__
             /    `88,       |88|       ,88'    \
            /        `88,    |88|    ,88'        \
           /____________`88,_/_,88`____________\
          /88888888888888888;8888;88888888888888888\
         /^^^^^^^^^^^^^^^^^^`/88\^^^^^^^^^^^^^^^^^^\
        /                    |88| \============,     \
       /_  __  __  __   _ __ |88|_|^  MERRY    | _ ___\
       |;:.                  |88| | CHRISTMAS! |      |
       |;;:.                 |88| '============'      |
       |;;:.                 |88|                     |
       |::.                  |88|                     |
       |;;:'                 |88|                     |
       |:;,                  |88|                     |
       '---------------------""""---------------------'
"@

$i = Get-Random -Minimum 1 -Maximum 6

$selected = ($msg1,$msg2,$msg3,$msg4,$msg5,$msg6 | Get-Random)
If([bool]!($i%2)) {
	Write-Host -ForegroundColor Green -Object $selected
        
	} else {
	Write-Host -ForegroundColor Red -Object $selected
	}


}

#class constructor
myChristmas() {
 $this.ElfName = $this.GetElfName()

 if ( (Get-Date).Second%2) {
    $this.List = [ListStatus]::Naughty
 }
 else {
    $this.List = [ListStatus]::Nice
 }
 
 #set the rest of the properties by invoking the defined
 #Refresh() method

 $this.Refresh()
}

}

[myChristmas]::new()

您将需要 PowerShell 5.0 或更高版本才能运行此文件。该脚本定义了类，然后创建它的实例，因此我将运行该脚本并将结果保存到变量中。

属性在类中定义。当我调用 New() 方法来创建对象的实例时，将执行构造函数会话中的代码。 $this 对象将引用新实例。在我的例子中，我调用一个名为 GetElfName() 的内部方法来设置 ElfName 属性。如果您查看该方法，您会发现它以对象时间（字符串）开头。在 PowerShell 类中使用方法时，必须指定它将返回的对象类型，或者使用 [void] 不返回任何内容。另请注意，如果您的方法将对象写入管道，则必须使用 return 关键字。

List 属性是从枚举设置的。这是一种创建预先确定的可能值数组的方法。就我而言，顽皮或友善，这或多或少是随机分配的。

其余属性通过调用内部 Refresh() 方法来设置，该方法计算距离圣诞节还剩多少天。如果通过管道将该对象传递给 Get-Member，您将看到该对象如何与类定义匹配。

我不想破坏所有的惊喜，所以我会让你尝试一些方法。但至少让我指出 GetPresent() 方法。如果您查看屏幕截图，您会发现有两种运行方法。这称为过载。如果查看类定义中的代码，您将看到该方法的多个条目，具有不同的参数选项。

顺便说一句，该方法只是从另一个枚举中返回一个或多个随机选择的项目作为礼物。希望你会得到你喜欢的东西。

享受我的礼物，祝您节日快乐，度过美好的 2017 年。