更新了 PowerShell 脚本分析器

去年，我为脚本专家 Ed Wilson 编写了一个侧边栏，并更新了他的 PowerShell 最佳实践一书。我使用 PowerShell 3.0 中的新解析器编写了一个脚本，该脚本将分析脚本并准备一份报告，显示它将运行哪些命令、必要的参数以及可能构成危险的任何内容。我还为 Hey Scripting Guy 博客撰写了一篇包含该脚本的文章。

在上周的 PowerShell 培训课程中，我们讨论了如何查看别人的代码并弄清楚它可能会做什么。我还演示了我的脚本。在演示过程中，我意识到我需要做一些修改。这是 Get-ASTScriptProfile.ps1 的版本 2。

#requires -version 3.0

#Get-ASTScriptProfile.ps1

<#
  ****************************************************************
  * DO NOT USE IN A PRODUCTION ENVIRONMENT UNTIL YOU HAVE TESTED *
  * THOROUGHLY IN A LAB ENVIRONMENT. USE AT YOUR OWN RISK.  IF   *
  * YOU DO NOT UNDERSTAND WHAT THIS SCRIPT DOES OR HOW IT WORKS, *
  * DO NOT USE IT OUTSIDE OF A SECURE, TEST SETTING.             *
  ****************************************************************
#>

<#
.Synopsis
Profile a PowerShell Script
.Description
This script will parse a PowerShell script using the AST to identify elements 
and any items that might be dangerous. The output is a text report which by 
default is turned into a help topic stored in your Windows PowerShell folder
under Documents, although you can specify an alternate location.

DETAILS
The script takes the name of a script to profile. You can specify a ps1 or 
psm1 filename. Using the AST the script will prepare a text report showing 
you any script requirements, script parameters, commands and type names. You 
will see all commands used including those that can't be resolved as well as 
those that I thought might be considered potentially dangerous such as cmdlets 
that use the verbs Remove or Stop. Because some people might invoke methods 
from .NET classes directly I've also captured all typenames. Most of them will
probably be related to parameters but as least you'll know what to look for. 

The report won't detail parameters from nested functions but you'll still see 
what commands they will use. The script uses Get-Command to identify commands 
which might entail loading a module. Most of the time this shouldn't be an 
issue but you still might want to profile the script in virtualized or test 
environment. 

Any unresolved command you see is either from a module that couldn't be loaded
or it might be an internally defined command. Once you know what to look for 
you can open the script in your favorite editor and search for the mystery 
commands.

Note that if the script uses application names like Main or Control for function
names, they might be misinterpreted. In that case, search the script for the name,
ie "main". 

This version will only analyze files with an extension of .ps1, .psm1 or .txt.
.Parameter Path
The path to the script file. It should have an extension of .ps1, .psm1 or
.bat.
.Parameter FilePath
The path for the report file. The default is your WindowsPowerShell folder.
This paramter has aliases of fp and out.
.Example
PS C:\> c:\scripts\Get-ASTScriptProfile c:\download\UnknownScript.ps1 

This will analyze the script UnknownScript.ps1 and show the results in a
help window. It will also create a text file in your Documents\WindowsPowerShell 
folder called UnknownScript.help.txt.
.Example
PS C:\> c:\scripts\Get-ASTScriptProfile c:\download\UnknownScript.ps1 -filepath c:\work

This command is the same as the first example except the help file will be created
in C:\Work.

.Notes
Version 2.0
Last Updated January 14, 2014
Jeffery Hicks (http://twitter.com/jeffhicks)

Learn more:
 PowerShell in Depth: An Administrator's Guide (http://www.manning.com/jones2/)
 PowerShell Deep Dives (http://manning.com/hicks/)
 Learn PowerShell 3 in a Month of Lunches (http://manning.com/jones3/)
 Learn PowerShell Toolmaking in a Month of Lunches (http://manning.com/jones4/)
 
.Inputs
None
.Outputs
Help topic
.Link
Get-Command
Get-Alias
#>

[cmdletbinding()]
Param(
[Parameter(Position=0,Mandatory,HelpMessage="Enter the path of a PowerShell script")]
[ValidateScript({Test-Path $_})]
[ValidatePattern( "\.(ps1|psm1|txt)$")]
[string]$Path,
[ValidateScript({Test-Path $_})]
[Alias("fp","out")]
[string]$FilePath = "$env:userprofile\Documents\WindowsPowerShell"
)

Write-Verbose "Starting $($myinvocation.MyCommand)"

#region setup profiling
#need to resolve full path and convert it
$Path = (Resolve-Path -Path $Path).Path | Convert-Path
Write-Verbose "Analyzing $Path"

Write-Verbose "Parsing File for AST"
New-Variable astTokens -force
New-Variable astErr -force

$AST = [System.Management.Automation.Language.Parser]::ParseFile($Path,[ref]$astTokens,[ref]$astErr)

#endregion

#region generate AST data

#include PowerShell version information
Write-Verbose "PSVersionTable"
Write-Verbose ($PSversionTable | Out-String)

$report=@"
Script Profile report for: $Path

******************
* PSVersionTable *
******************
$(($PSversionTable | Out-String).TrimEnd())

"@

Write-Verbose "Getting requirements and parameters"
$report+=@"

******************
*  Requirements  *
******************
$(($ast.ScriptRequirements | out-string).Trim())

******************
*  Parameters    *
******************
$(($ast.ParamBlock.Parameters | 
 Select Name,DefaultValue,StaticType,Attributes |
 Format-List | Out-String).Trim())
 
"@

Write-Verbose "Getting all command elements"

$commands = @()
$unresolved = @()

$genericCommands = $astTokens | 
where {$_.tokenflags -eq 'commandname' -AND $_.kind -eq 'generic'} 

$aliases = $astTokens | 
where {$_.tokenflags -eq 'commandname' -AND $_.kind -eq 'identifier'} 

Write-Verbose "Parsing commands"
foreach ($command in $genericCommands) {
    Try {
       $commands+= Get-Command -Name $command.text -ErrorAction Stop
    }
    Catch {
      $unresolved+= $command.Text
    }
}

foreach ($command in $aliases) {
Try {
       $commands+= Get-Command -Name $command.text -erroraction Stop |
       foreach { 
         #get the resolved command
         Get-Command -Name $_.Definition  
       }
    }
    Catch {
        $unresolved+= $command.Text
    }
}

Write-Verbose "All commands"
$report+=@"

******************
*  All Commands  *
******************
$(($Commands | Sort -Unique | Format-Table -autosize | Out-String).Trim())

"@

Write-Verbose "Unresolved commands"
$report+=@"

******************
*  Unresolved    *
******************
$($Unresolved | Sort -Unique | Format-Table -autosize | Out-String)
"@

Write-Verbose "Potentially dangerous commands"
#identify dangerous commands
$danger="Remove","Stop","Disconnect","Suspend","Block",
"Disable","Deny","Unpublish","Dismount","Reset","Resize",
"Rename","Redo","Lock","Hide","Clear"

$danger = $commands | where {$danger -contains $_.verb}

#get type names, some of which may come from parameters
Write-Verbose "Typenames"
$report+=@"

******************
*  TypeNames     *
******************
$($asttokens | where {$_.tokenflags -eq 'TypeName'} | 
Sort @{expression={$_.text.toupper()}} -unique | 
Select -ExpandProperty Text | Out-String)
"@

$report+=@"

******************
*  Warning       *
******************
$($danger | Format-Table -AutoSize | Out-String)
"@

#endregion

Write-Verbose "Display results"
#region create and display the result

#create a help topic file using the script basename
$basename = (Get-Item $Path).basename     
#stored in the Documents folder
$reportFile = Join-Path -Path $FilePath -ChildPath "$basename.help.txt"

Write-Verbose "Saving report to $reportFile"
#insert the Topic line so help recognizes it
"TOPIC" | Out-File -FilePath $reportFile -Encoding ascii 

#create the report
$report | Out-File -FilePath $reportFile -Encoding ascii -Append

#view the report with Get-Help and -ShowWindow
Get-Help (Join-Path -Path $FilePath -ChildPath $basename) -ShowWindow

#endregion

Write-Verbose "Profiling complete."

#end of script

我发现的一件事是 AST 不喜欢解析没有绝对路径和解析路径的文件。我遇到了错误，因为脚本位于类似 Scripts: 的 PSDrive 上，解析为 C:\Scripts。解决方案是解决它，如果使用 .\file.ps1 这样的路径，然后转换路径。

$Path = (Resolve-Path -Path $Path).Path | Convert-Path

我还发现，如果脚本包含名称如 Main 或 Control 的函数，解析器（至少以我使用它的方式）会将其检测为类似 main.cpl 的应用程序。您应该为函数指定一个有意义且标准的名称，并尽量避免使用“可能”被误解的名称，这是有原因的。称为记事本的功能可能不是一个好主意。我修改了帮助以表明这种潜在的误解。我不确定我还能做些什么。

我所做的其他一些更改是为了灵活性和清晰度。我现在将 PSVersion 信息包含在报告中。参数信息现在显示为列表以避免丢失任何数据。我为脚本文件添加了一个验证参数，以便您只能分析 .ps1、.psm1 或 .txt 文件。

最后，我添加了一个参数，以便您可以指定输出文件的文件夹。默认位置为 Documents\WindowsPowerShell。您无需指定文件名，只需指定路径，例如 C:\Scripts 或 $env:temp。

PS Scripts:\> .\Get-ASTScriptProfile.ps1 .\Convert-WindowsImage.ps1 -out c:\work

这将生成如下帮助主题报告：