cliHelper.core

0.1.1

Public/Network/Get-UrlContent.ps1

function Get-UrlContent {
  <#
.SYNOPSIS
    To get the HTML content of a specified URL
.DESCRIPTION
    To get the HTML content of a specified URL
.PARAMETER URL
    The URL string, which should begin with "https://" or "http://"
.PARAMETER IgnoreSslError
    To ignore any SSL errors that are generated
.NOTES
    This function only exists for PowerShell versions prior to the inclusion of Invoke-WebRequest
.EXAMPLE
    Get-UrlContent -URL "http://www.google.com"
    Would return:
    The HTML content that is found on Google's homepage
.EXAMPLE
    Get-UrlContent -URL "https://secureServer"
    Assuming the computer does not have a valid certificate for secureServer then this would return:
    $Null
.EXAMPLE
    Get-UrlContent -URL "https://secureServer" -IgnoreSslError
    Assuming the computer does not have a valid certificate for secureServer and you wish to override the SSL error then this would return:
    The HTML content that is found on secureServer's homepage
.OUTPUTS
    Either $Null if any errors exist or a [string] if successful
#>

  [CmdletBinding()]
  [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseProcessBlockForPipelineCommand', '')]
  Param (
    [parameter(ValueFromPipeLine, HelpMessage = 'Add help message for user', ValueFromPipeLineByPropertyName, Mandatory)]
    [string] $URL,

    [parameter()]
    [switch] $IgnoreSslError
  )

  begin {
    Write-Invocation $MyInvocation
    $oldEA = $ErrorActionPreference
    $ErrorActionPreference = 'continue'
    Out-Verbose "Saving current value of `$ErrorActionPreference [$($oldEa)] and setting it to 'Stop'"
  }

  process {
    if ($IgnoreSslError) {
      Out-Verbose 'Turning on IgoreSslError'
      [System.Net.ServicePointManager]::ServerCertificateValidationCallBack = { $true }
    }
    $htmlContent = $null
    Out-Verbose 'Creating a webclient'
    $webClient = New-Object -TypeName System.Net.WebClient
    Out-Verbose "Requesting content from [$($URL)]"
    try {
      $htmlContent = $webClient.downloadstring($URL)
    } catch {
      Write-Error -Message "Could not connect to [$($URL)]"
    } finally {
      if ($IgnoreSslError) {
        Out-Verbose 'Turning off IgoreSslError'
        [System.Net.ServicePointManager]::ServerCertificateValidationCallBack = { $false }
      }
    }

    Out-Verbose 'Disposing of webClient connection'
    $webClient.Dispose()
    Remove-Variable -Name webClient
    if ($htmlContent) {
      Out-Verbose 'Successful download of HTML content'
      Write-Output -InputObject $htmlContent
    } else {
      Out-Verbose 'Unsuccessful download of HTML content'
      break
    }
  }

  end {
    Out-Verbose "Resetting value of `$ErrorActionPreference back to [$($oldEa)]"
    $ErrorActionPreference = $oldEA
    Out-Verbose $fxn "Complete."
  }
}