update-modules.ps1

<# 
.SYNOPSIS 
 Download & Update the agent with the latest versions from the repository
 
 
.DESCRIPTION 
 Setup and maintain agent scripts with latest version from the git repository.
 If you provide no commandline options it checks for updates for the core graph-commit scripts.
 

.NOTES 
┌─────────────────────────────────────────────────────────────────────────────────────────────┐ 
│ update-modules.ps1                                                                          │ 
├─────────────────────────────────────────────────────────────────────────────────────────────┤ 
│   DATE        : 11.06.2019 				               	                            │ 
│   AUTHOR      : Paul Drangeid 			                                              │ 
│   SITE        : https://github.com/pdrangeid/graph-commit                                   │ 
└─────────────────────────────────────────────────────────────────────────────────────────────┘ 
#> 

param (
    [string]$gitrepo,
    [string]$gitfile,
    [string]$destpath
    )

$companyname="Blue Net Inc"
$path = $("$Env:Programfiles\$companyname")
$localtz=Get-TimeZone | Select-Object Id -ExpandProperty Id
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

function ConvertUTC {
param($time, $fromTimeZone)
  $oFromTimeZone = [System.TimeZoneInfo]::FindSystemTimeZoneById($fromTimeZone)
  $utc = [System.TimeZoneInfo]::ConvertTimeToUtc($time, $oFromTimeZone)
  return $utc
} # End ConvertUTC
function ConvertUTCtoLocal{
param([String] $UTCTime)
$strCurrentTimeZone = (Get-WmiObject win32_timezone).StandardName
$TZ = [System.TimeZoneInfo]::FindSystemTimeZoneById($strCurrentTimeZone)
$LocalTime = [System.TimeZoneInfo]::ConvertTimeFromUtc($UTCTime, $TZ)
return $LocalTime
} # End ConvertUTCtoLocal
Function get-updatedgitfile([string]$reponame,[string]$repofile,[string]$localfilename){
      # This function will query github API at the provided $reponame and $repofile and download if the $localfilename is older or missing.
      # NOTE: unauthentication API queries to github (like this one) are rate-limited to 60 per hour (per IP address)
      # So be sure you are only checking for a few files, and if it is a scheduled job, be sure you won't exceed this limit.
      # You could add authenitcation to this function to avoid the 60/hr rate limitation.

      $githuburl="https://api.github.com/repos/$reponame/commits?path=$repofile&page1&per_page=1"
      Try{
            $Restresult=(Invoke-RestMethod $githuburl -Method 'Get' -Headers @{Accept = "application/json"} -ErrorVariable RestError -ErrorAction SilentlyContinue -TimeoutSec 30)
      }
      Catch {
            $ErrorMessage = $_.Exception.Message
            if ($_.Exception.ItemName -like '*rate limit exceeded*') {
                  Write-Warning "`nExceeded rate limit when querying github API: $githuburl"
                  return $false
            }

            if ($ErrorMessage -eq 'Unable to connect to the remote server'){
                  Write-Warning "`nUnable to connect to the remote server $githuburl"
                  return $false
            }
            write-host "Error Message $ErrorMessage `nFailed Item:$_.Exception.ItemName `nhttp Response:$_.Exception.Response`n"
                  return $false
      }
      #Get the date of the last commit for the repository file requested.  WE assume the repository is storing in UTC stamps.
      [datetime]$therepofiledate=$Restresult.commit[0].author.date | get-date -Format "yyyy-MM-ddTHH:mm:ss"
      If (Test-Path -path $localfilename) {
            $lastModifiedDate = (Get-Item $localfilename).LastWriteTime | get-date -Format "yyyy-MM-ddTHH:mm:ss"
            $localfiletime = ConvertUTC $lastModifiedDate $localtz
      if ($localfiletime -ge $therepofiledate){
           Write-Host "$localfilename is already present and up-to-date"
      }#end if (local file exists, and is the same or newer datestamp than that of the repository)
      else {
            write-host "$repofile will be updated..."
            $downloadfile=$true
      }#end else (file exists, but is older than the one in the repository)
      }#end if (the file DOES exists in the expected local path)

      else {
            $localtest="$repofile is not present and will be downloaded from the repository"
            $downloadfile=$true
      }# end else (local file doesn't exist in the expected local path)     
      Write-host $localtest
      
            if ($downloadfile -eq $true) {
            write-host "Downloading $repofile ($therepofiledate) from https://raw.githubusercontent.com/$reponame/master/$repofile`n"
            $dlurl="https://raw.githubusercontent.com/$reponame/master/$repofile"
            $client = new-object System.Net.WebClient
            Try{
            #Write-Host "Downloading $dlurl to $localfilename"
            $client.DownloadFile($dlurl,$localfilename) 
            $localtimestamp = ConvertUTCtoLocal $therepofiledate | get-date
            #Convert the UTC of the repo file to the localtime, then set the local file's lastmodified property to the proper timestamp
            Get-ChildItem  $localfilename | ForEach-Object {$_.LastWriteTime = $localtimestamp}

            }
            Catch{
            $ErrorMessage = $_.Exception.Message
            $FailedItem = $_.Exception.ItemName
            $error[0].Exception.ToString()
            Write-Host $ErrorMessage
            Write-Host $FailedItem
            write-host "the error is "$error[0].Exception.ToString()
            }
            }# End Download was True
      }# End Function get-updatedgitfile

if (![string]::IsNullOrEmpty($gitrepo))  {      
      if ([string]::IsNullOrEmpty($gitfile))  {Write-Host "-gitrepo 'repository path' -gitfile gitfilename.ext must both be specified on the commandline for custom updates."
       exit}
      if ([string]::IsNullOrEmpty($destpath))  {$destpath=$PSScriptRoot}
      
      If(!(test-path $destpath))
      {
            New-Item -ItemType Directory -Force -Path $destpath
      }
      get-updatedgitfile $gitrepo "$gitfile" "$destpath\$gitfile"
      exit
}

If(!(test-path $path))
{
      New-Item -ItemType Directory -Force -Path $path
}
$path = $("$Env:Programfiles\$companyname\Graph-Commit")
If(!(test-path $path))
{
      New-Item -ItemType Directory -Force -Path $path
}

$rpath = "pdrangeid/graph-commit"
get-updatedgitfile $rpath "set-regcredentials.ps1" "$path\set-regcredentials.ps1"
get-updatedgitfile $rpath "update-modules.ps1" "$path\update-modules.ps1"
get-updatedgitfile $rpath "bg-sharedfunctions.ps1" "$path\bg-sharedfunctions.ps1"
get-updatedgitfile $rpath "get-cypher-results.ps1" "$path\get-cypher-results.ps1"

exit