Cloudflare DDNS for Windows

ddns-cf-win.ps1

# Create or Update a Cloudflare domain or subdomain with your current IP, and schedule a recurring run via Task Scheduler

# (Optional but recommended) Rename this to include the subdomain name, such as ddns-cf-win_x.example.com.ps1 or simply x.example.com.ps1
# Place this somewhere you're comfortable running it from (C:/PortablePrograms/ddns-cf/)
# Right-click and Run in PowerShell
# This will run once, and schedule itself to run via Task Scheduler every x minutes (will ask for Admin priviledges for this)
# If the Task already exists for this record, it won't be duplicated
# Can run multiple of these for different records (task name includes the recordFullName)

# Stop the script on any errors
$ErrorActionPreference = "Stop"

# --- Cloudflare DNS Update Part ---

# Cloudflare settings
$apiKey = "???"             # or token
$zoneID = "???"
$domain = "example.com"
$recordName = "subdomain"   # or @
$updateInterval = 1  				# minutes


# --- Cloudflare DNS Update Part ---

# Stop the script on any errors
$ErrorActionPreference = "Stop"

function Get-PublicIP {
    $urlList = @(
        "http://ipinfo.io/json",
        "https://api.ipify.org",
        "https://ifconfig.me/ip",
        "https://icanhazip.com",
        "https://ipinfo.io/ip"
    )

    foreach ($url in $urlList) {
        try {
            if ($url -eq "http://ipinfo.io/json") {
                $response = Invoke-RestMethod -Uri $url
                return $response.ip
            } else {
                $response = Invoke-WebRequest -Uri $url
                return $response.Content.Trim()
            }
        } catch {
            Write-Host "Failed to get IP from $url. Trying next..."
        }
    }

    throw "All IP address providers failed."
}

$recordFullName = if ($recordName -eq "@") { $domain } else { "${recordName}.${domain}" }

try {
    $publicIp = Get-PublicIP
    Write-Host "$recordFullName -> $publicIp"
} catch {
    Write-Host "Failed to retrieve public IP address: $_"
    exit
}

try {
    $headers = @{
        "Authorization" = "Bearer $apiKey"
        "Content-Type" = "application/json"
    }
	
	$recordUri = "https://api.cloudflare.com/client/v4/zones/$zoneID/dns_records?name=$recordFullName"
	$recordID = $null
	try {
		#Write-Host "1 recordUri: $recordUri"
		$response = Invoke-RestMethod -Uri "$recordUri" -Method Get -Headers $headers
		#Write-Host "2 response: $response"
		$recordID = ($response.result | Where-Object { $_.name -eq $recordFullName }).id
		#Write-Host "3 recordID: $recordID"
	} catch {
		Write-Host "Error fetching record ID. Status Code: $($_.Exception.Response.StatusCode.Value__) Message: $($_.Exception.Message)"
		$responseContent = $_.Exception.Response.GetResponseStream()
		$reader = New-Object System.IO.StreamReader($responseContent)
		$responseString = $reader.ReadToEnd()
		Write-Host "Response Content: $responseString"
		$recordID = $null
	}
	
	$updateUri = "https://api.cloudflare.com/client/v4/zones/$zoneID/dns_records/$recordID"
	$body = @{
		type = "A"
		name = $recordName
		content = $publicIp
		ttl = 1
		proxied = $false
	} | ConvertTo-Json
	if ($recordID) {
		# Update
		Invoke-RestMethod -Uri "$updateUri" -Method Put -Headers $headers -Body $body
		Write-Host "DNS record updated to IP: $publicIp"
	} else {
		# Create
		Invoke-RestMethod -Uri "$updateUri" -Method Post -Headers $headers -Body $body
		Write-Host "OK"
	}
} catch {
	Write-Host "Error fetching record ID: $($_.Exception.Message)"
	Write-Host "Status Code: $($_.Exception.Response.StatusCode)"
	Write-Host "Response Content: $($_.Exception.Response.Content)"
    exit
}


# --- Task Scheduler Part ---

$taskName = "ddns-cf-win-$recordFullName"

# Check if the task already exists
if (-not (Get-ScheduledTask -TaskName $taskName -ErrorAction SilentlyContinue)) {

	# Function to check if running as Administrator
	function Test-Admin {
		$currentUser = New-Object Security.Principal.WindowsPrincipal $([Security.Principal.WindowsIdentity]::GetCurrent())
		$currentUser.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
	}

	# Check if running as Administrator
	if (-not (Test-Admin)) {
		#Write-Error "Please run as Administrator if you want to schedule the recurring task"
		#exit
		
		# Relaunch as an administrator (Cloudflare API will be called a 2nd time, but that's fine)
		if ($elevated) {
			# tried to elevate, did not work, aborting
		} else {
			Start-Process powershell.exe -Verb RunAs -ArgumentList ('-noprofile -noexit -file "{0}" -elevated' -f ($myinvocation.MyCommand.Definition))
		}
		exit
	}

    # Define script path
    $scriptPath = $MyInvocation.MyCommand.Definition

    # Task parameters
    $action = New-ScheduledTaskAction -Execute "Powershell.exe" -Argument "-File `"$scriptPath`""
    $trigger = New-ScheduledTaskTrigger -Once -At (Get-Date) -RepetitionInterval (New-TimeSpan -Minutes $updateInterval) -RepetitionDuration (New-TimeSpan -Days 10000)
    $principal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -LogonType ServiceAccount

    # Register the task
	  try {
		  Register-ScheduledTask -Action $action -Trigger $trigger -TaskName $taskName -Description "Update Cloudflare DNS for $recordFullName every $updateInterval minute(s)" -Principal $principal
		  Write-Host "Task Scheduler entry created for $scriptPath. Make sure to keep the script in the same place. To cancel this task, search for '$taskName' in Task Scheduler (usually under your username)"
    } catch {
        Write-Host "Failed to create Task Scheduler entry: $_"
        exit
    }
} else {
    Write-Host "Task Scheduler entry already exists. All good"
}