powershell网络蜘蛛解决乱码问题

抓取（爬取）网上信息的脚本程序，俗称网络蜘蛛。
powershell中自带了这样的两个命令，【Invoke-WebRequest】和【Invoke-RestMethod】，但这两个命令有时候会乱码。

现在转帖分享， 某个【歪果仁】写的脚本。来源于 墙外出处： https://gist.github.com/angel-vladov/9482676

核心代码

function Read-HtmlPage {
param ([Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true)][String] $Uri)

# Invoke-WebRequest and Invoke-RestMethod can't work properly with UTF-8 Response so we need to do things this way.
[Net.HttpWebRequest]$WebRequest = [Net.WebRequest]::Create($Uri)
[Net.HttpWebResponse]$WebResponse = $WebRequest.GetResponse()
$Reader = New-Object IO.StreamReader($WebResponse.GetResponseStream())
$Response = $Reader.ReadToEnd()
$Reader.Close()

# Create the document class
[mshtml.HTMLDocumentClass] $Doc = New-Object -com "HTMLFILE"
$Doc.IHTMLDocument2_write($Response)

# Returns a HTMLDocumentClass instance just like Invoke-WebRequest ParsedHtml
$Doc

#powershell 传教士 转帖并修改的文章 2016-01-01, 允许再次转载，但必须保留名字和出处，否则追究法律责任

}

原文函数

function Read-HtmlPage {
  param ([Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true)][String] $Uri)

  # Invoke-WebRequest and Invoke-RestMethod can't work properly with UTF-8 Response so we need to do things this way.
  [Net.HttpWebRequest]$WebRequest = [Net.WebRequest]::Create($Uri)
  [Net.HttpWebResponse]$WebResponse = $WebRequest.GetResponse()
  $Reader = New-Object IO.StreamReader($WebResponse.GetResponseStream())
  $Response = $Reader.ReadToEnd()
  $Reader.Close()

  # Create the document class
  [mshtml.HTMLDocumentClass] $Doc = New-Object -com "HTMLFILE"
  $Doc.IHTMLDocument2_write($Response)
  
  # Returns a HTMLDocumentClass instance just like Invoke-WebRequest ParsedHtml
  $Doc
}

PowerShell function you can use for reading UTF8 encoded HTML pages content. The built in Invoke-WebRequest and Invoke-RestMethod fail miserably.