Function – Devops Scripts & Patterns

PowerShell Function To Add Filesystem Permissions

2023-03-22 / PowerShell Scripting / Tim van Kooten Niekerk

Recently wrote a simple function to add permission to filesystem resources. It defaults to modify permissions, but can also be another basic permission for instance: Read, Write or FullControl.

function fnAddFilesystemPermissions()
{
  param (
    [string]$sPath,
	[string]$sUserName,
	[string]$sPermission = "Modify"
  )

  # Add write permissions to a file using powershell...
  $accessRule = New-Object System.Security.AccessControl.FileSystemAccessRule($sUserName,$sPermission,"Allow")
  $acl = Get-ACL -Path $sPath
  $acl.SetAccessRule($accessRule)
  $acl | Set-Acl -Path $sPath

  # Return permissions...
  return (Get-ACL -Path $sPath).Access | Format-Table 
}

PS> fnAddFilesystemPermissions -sPath “C:\Path\To\Resource” -sUserName “User-Principle-Name” [-sPermission “FullControl“]

PowerShell Hex 2 Ascii Function

2017-05-24 / PowerShell Scripting / Tim van Kooten Niekerk

Function to convert a HEX value to Ascii. Example:

>fnHex2Ascii -HexValue “00000000”

function fnHex2Ascii()
{
  param (
    [string]$HexString
	)
  
  Clear-Variable -Name sAscii -ErrorAction SilentlyContinue
  $HexString -Split '(.{2})' | %{ if ($_ -ne "") { $sAscii+=[CHAR]([CONVERT]::toint16($_,16)) } }

  # Return metadata and body...
  return $sAscii 
}

Ascii Binary Convert Function Hex

PowerShell Webservices Probe

2014-06-24 / PowerShell Scripting / Tim van Kooten Niekerk

The following script reads URL’s from an array to check if specific web services are online. When the script finds that one or more services are offline it sends an e-mail message (HTML). A TEXT version of the message is created in the Windows EventLog.

Het script uses custum functions: fnSendMail en fnWriteEventLog om berichten af te handelen.

# Global config settings...
[string]$sSMTPServer1 = "smtp.example.org"
[string]$sSubject1 = "EXAMPLE:WebService probes..."
[string]$sToAddress1 = "test@example.org"
[string]$sEventLogSource = "EVENTLOGSOURCE"
[switch]$swAlarm = $false
[array]$aWebServices1 = @(
   "https://example.org/webService?WSDL",
   "https://example.org/webService?WSDL",
)

# Functions and procedures...
function fnProbeWebSvc() {
  param (
    [string]$sWebSvcWSDL
  )
  $oWebSvc1 = New-WebServiceProxy -Uri $sWebSvcWSDL
  if ($oWebSvc1) {
    [switch]$swWebSvcIsAlive = $true
  } else {
    [switch]$swWebSvcIsAlive = $false
  }  
  return $swWebSvcIsAlive
}

# Start Main script...
# Create array for results...
[array]$aWebServiceState = @()

# Fill table from array...
foreach ($row1_aWebServices1 in $aWebServices1) {
  $oWebServiceState = New-Object PSObject -Property @{
    'WebService' = $row1_aWebServices1
    'IsAlive' = (fnProbeWebSvc -sWebSvcWSDL $row1_aWebServices1) }
  # FLip Alarm status if fnProbeWebSvc return value is false...  
  if ($oWebServiceState.IsAlive -eq $false) {[switch]$swAlarm = $true}
  $aWebServiceState += $oWebServiceState
}

# Build HTML and TEXT body w. array data if alarm status is set to true...
if ($swAlarm -eq $true) {
  
  # Body header HTML...
  $sbBody1_HTML = New-Object System.Text.StringBuilder
  [void]$sbBody1_HTML.Append("<html><head><title></title></head><body>`r`n")
  [void]$sbBody1_HTML.Append("<table><tbody><tr bgcolor='grey'><th>WebService</th><th>IsAlive</th></tr>`r`n")

  # Body header TEXT...
  $sbBody1_TEXT = New-Object System.Text.StringBuilder
  [void]$sbBody1_TEXT.Append("Webservice(s) offline. Contact your administrators.`r`n`r`n")

  # Build table rows from array...
  foreach ($row1_aWebServiceState in $aWebServiceState) {
    # Build table rows HTML...
    [void]$sbBody1_HTML.Append("<tr bgcolor='lightblue'><td>")
    [void]$sbBody1_HTML.Append($row1_aWebServiceState.WebService)
    # Row Coloring...
    if ($row1_aWebServiceState.IsAlive -eq $true) {
      [void]$sbBody1_HTML.Append("</td><td bgcolor='lightgreen'>")
    } else {
      [void]$sbBody1_HTML.Append("</td><td bgcolor='lightpink'>")
    }
    [void]$sbBody1_HTML.Append($row1_aWebServiceState.IsAlive)
    [void]$sbBody1_HTML.Append("</td></tr>")

    # Build table rows TEXT (only show failed services...
      if ($row1_aWebServiceState.IsAlive -eq $false) {
        [void]$sbBody1_TEXT.Append($row1_aWebServiceState.WebService)
        [void]$sbBody1_TEXT.Append(": ")
        [void]$sbBody1_TEXT.Append($row1_aWebServiceState.IsAlive)
        [void]$sbBody1_TEXT.Append("`r`n")
      }
  }

  # Mail body footer...
  [void]$sbBody1_HTML.Append("</tbody></table>`r`n")
  [void]$sbBody1_HTML.Append("<html><head><title></title></head><body>`r`n")

  # Send HTML body in mail to admins...
  [string]$sBody1 = $sbBody1_HTML.ToString()
  fnSendMail -sSMTPSrvrName $sSMTPServer1 -sFrom (fnGetFQDN -swIsEmail) -sTo $sToAddress1 -sSubject $sSubject1 -sBody $sBody1 -swIsBodyHTML

  # Send text body to eventlog...
  fnWriteEventLog -sNode "NODENAME" -sMessage $sbBody1_TEXT.ToString() 
}

E-mail EventLog Function HTML StringBuilder WebService WSDL XML

PowerShell Get Local Machine FQDN Function

2014-06-24 / PowerShell Scripting / Tim van Kooten Niekerk

The example function below retrieves the FQDN of the machine on which the script is running. The switch option swIsEmail can be activated to construct a noreply email address.

function fnGetFQDN() {
  param (
    [switch]$swIsEmail = $false
  )
  $oNETIP = [System.Net.NetworkInformation.IPGlobalProperties]::GetIPGlobalProperties()
  if ($swIsEmail -eq $true) {
    [string]$Return1 = "noreply@" + $oNETIP.HostName + "." + $oNETIP.DomainName
  } else {
    [string]$Return1 = $oNETIP.HostName + "." + $oNETIP.DomainName
  }  
  return $Return1
}

FQDN Function GetIPGlobalProperties Hostname IP

PowerShell SQL Query Function

2014-06-24 / PowerShell Scripting / Tim van Kooten Niekerk

The function below can be used to a query to a database. The script returns any error as a result (2 lines).

function fnSQLCmd([string]$sInstance, [string]$sQuery, [string]$sDatabase) {
  # Register SQPPS Module...
  $oSQLPSModule = Get-Module | Where {$_.name -eq "SQLPS" }
  if ($oSQLPSModule.Count -eq 0) {
    Import-Module "SQLPS" -WarningAction SilentlyContinue
  }

  if ($sDatabase) {
    [string]$sQuery = "Invoke-SqlCmd -ServerInstance " + $sInstance + " -Database " + $sDatabase + " -QueryTimeout 30 -Query `"" + $sQuery + "`" ; if (`$? -eq `$false) { @{`"ERROR0`" = `$error[0]}; @{`"ERROR1`" = `$error[1]} }" 
  } else {
    [string]$sQuery = "Invoke-SqlCmd -ServerInstance " + $sInstance + " -QueryTimeout 30 -Query `"" + $sQuery + "`" ; if (`$? -eq `$false) { @{`"ERROR0`" = `$error[0]}; @{`"ERROR1`" = `$error[1]} }" 
  }
  return Invoke-Expression $sQuery
}

database Function Invoke-Sqlcmd MSSQL Query SQLPS

PowerShell Write Windows Eventlog

2014-06-24 / PowerShell Scripting / Tim van Kooten Niekerk

The following function can be used to write to the Windows EventLog in a standard way. Some of the scripts on this site use this custum function.

function fnWriteEventLog() {
  param (
    [string]$sNode, 
    [string]$sMessage, 
    [string]$sEventLogSource = "DEFAULTLOGSOURCE", 
    [int]$iEventID = 1001, 
    [string]$sType = "Error"
  )
  if ( ($sNode) -and ($sMessage) ) {
    [string]$sFormatMessage = "Node: " + $sNode + "`r`n`r`n" + $sMessage
    Write-EventLog -LogName Application -Source $sEventLogSource -EntryType $sType -EventID $iEventID -Message $sFormatMessage
  } else {
    return "ERROR: fnWriteEventLog missing arguments..."
  }
}

EventLog Function Write

PowerShell Unzip Function

2013-04-08 / PowerShell Scripting / Tim van Kooten Niekerk

A small PowerShell function for unzipping a file.

function fUnzip([string]$sZIPFileName, [string]$sExtractToDir) {
  $oShell = new-object -com shell.application
  $oZIPFile = $oShell.namespace("$sZIPFileName")
  $oExtractTo = $oShell.namespace("$sExtractToDir")
  $oExtractTo.Copyhere($oZIPFile.items())
}

File Function Unzip

PowerShell TCP Socket Function

2013-03-18 / PowerShell Scripting / Tim van Kooten Niekerk

The PowerShell function example below can be used to transmit information using the TCP protocol. For example, to perform an HTTP GET command on a website.

function fnTCPSock([string]$sHostName, [string]$sPort, [string]$sScript) {
  # Converteer script string to byte for write stream...
  [byte[]]$byteScript = [System.Text.Encoding]::ASCII.GetBytes($($sScript))
  # Open 4096 Bytes buffer for read stream...
  [byte[]]$byteBuffer = New-Object System.Byte[] 16384
  
  # Connect to host...
  $oTCPSock = New-Object System.Net.Sockets.TcpClient($sHostName, $sPort)
  $oStream = $oTCPSock.GetStream() 
  
  # Feed script(byte) tot write stream...
  $oStream.Write($byteScript, 0, $byteScript.Length)

  # Return read buffer converted to string...
  [string]$sCount = $oStream.Read($byteBuffer, 0, 16384)
  return [System.Text.Encoding]::ASCII.GetString($byteBuffer, 0, $sCount) 

  # Close objects...
  $oResult.Close()
  $oSockTCP.Close()
}

[string]$sScript1 = "GET / HTTP/1.1`r`nAccept: text/html`r`nHost: [virtualhostname]`r`nReferer: http://host.domain.name/site/`r`n`r`n`r`n"
[string]$sResult1 = fnTCPSock "hostname" "80" $($sScript1)

Function GET HTTP Network TCP Telnet

PowerShell E-mail Function

2011-08-08 / PowerShell Scripting / Tim van Kooten Niekerk

Met behulp van onderstaande functie kun je vanuit een script een e-mail verzenden. De procedure is in een functie gegoten waardoor deze gemakkelijk kan worden hergebruikt. Deze functie werkt zowel in PowerShell V1 als PowerShell V2. Deze functie maakt gebruik van een andere functie fnWriteEventLog t.b.v. schrijfacties naar het Windows EventLog.

function fnSendMail()
{
  param (
    [string]$sSMTPSrvrName, 
    [string]$sFrom, 
    [string]$sTo, 
    [string]$sSubject, 
    [string]$sBody, 
    [string]$sAttFileName, 
    [switch]$swIsBodyHTML = $false
    )

  if (($sSMTPSrvrName) -and ($sFrom) -and ($sTo) -and $sSubject) {
  
    # Declare mail objects...
    $oMessage = new-object Net.Mail.MailMessage
    $oSMTP = new-object Net.Mail.SmtpClient($sSMTPSrvrName)

    # Pass values to object...
    $oMessage.From = $sFrom
    $oMessage.To.Add($sTo)
    $oMessage.Subject = $sSubject
    $oMessage.IsBodyHtml = $swIsBodyHTML
    $oMessage.BodyEncoding = ([System.Text.Encoding]::UTF8)
    if ($sBody) { $oMessage.Body = $sBody }

    # Add attachment...
    if ($sAttFileName) {
      $oAttachment = new-object Net.Mail.Attachment($sAttFileName)
      $oMessage.Attachments.Add($oAttachment)
    }

    $oSMTP.Send($oMessage)
    if ($? -eq "True") {
      #fnWriteEventLog -sNode (fnGetFQDN) -sMessage "Email has been sent..." -iEventID 1 -sType "Information"
      return "INFO: Email has been sent..." 
    } else {
      fnWriteEventLog -sNode (fnGetFQDN) -sMessage "Error sending mail..." -iEventID 501
      return "ERROR: Error sending e-mail..."
    }

  } else {
    fnWriteEventLog -sNode (fnGetFQDN) -sMessage "fSendMail argument missing..." -iEventID 501
    return "ERROR: Argument(s) missing. [fnSendMail `"SMTPServerName`" `"From`" `"To`" `"Subject`" `"Body`" (`"AttachFileName`" `"isBodyHTML`")]"
  }
}

E-mail Function