(PowerShell) Get Google API Access Token using JSON Private Key using NIST Time Server Date/Time

Demonstrates how to get a Google API access token using a JSON service account private key, using the NIST time server date/time rather than the local system date/time.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# First, let's get the current date/time from time-c.nist.gov
$socket = New-Object Chilkat_9_5_0.Socket

# Connect to an NIST time server and read the current date/time
$maxWaitMs = 8000
$useTls = $false
$success = $socket.Connect("time-c.nist.gov",37,$useTls,$maxWaitMs)
if ($success -ne $true) {
    $($socket.LastErrorText)
    exit
}

# The time server will send a big-endian 32-bit integer representing
# the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
# The ReceiveInt32 method will receive a 4-byte integer, but returns
# $true or $false to indicate success.  If successful, the integer
# is obtained via the ReceivedInt property.
$bigEndian = $true
$success = $socket.ReceiveInt32($bigEndian)
if ($success -ne $true) {
    $($socket.LastErrorText)
    exit
}

$dt = New-Object Chilkat_9_5_0.CkDateTime
$dt.SetFromNtpTime($socket.ReceivedInt)

# Show the current local date/time
$bLocalTime = $true
$("Current local date/time: " + $dt.GetAsRfc822($bLocalTime))

$maxWaitMs = 10
$socket.Close($maxWaitMs)

# ------------------------------------------------------------------------
# OK, we have the current date/time.  We'll use it to set the IAT property
# in the code below.

# First load the JSON key into a string.
$fac = New-Object Chilkat_9_5_0.FileAccess
$jsonKey = $fac.ReadEntireTextFile("qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json","utf-8")
if ($fac.LastMethodSuccess -ne $true) {
    $($fac.LastErrorText)
    exit
}

# A JSON private key should look like this:

# 	{
# 	  "type": "service_account",
# 	  "project_id": "chilkattest-1350",
# 	  "private_key_id": "fa2e36ee26986eab628b59868af8bec1d1c64c38",
# 	  "private_key": "-----BEGIN PRIVATE KEY-----\nMIIEvgIjFa...28N64N2n1E4FYzBZjSdy\n-----END PRIVATE KEY-----\n",
# 	  "client_email": "598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a@developer.gserviceaccount.com",
# 	  "client_id": "598922945226-00rb0ppfg0snd9jo7bhvd4v17jtj2d3a.apps.googleusercontent.com",
# 	  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
# 	  "token_uri": "https://accounts.google.com/o/oauth2/token",
# 	  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
# 	  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a%40developer.gserviceaccount.com"
# 	}

$gAuth = New-Object Chilkat_9_5_0.AuthGoogle
$gAuth.JsonKey = $jsonKey

# Choose a scope.
$gAuth.Scope = "https://www.googleapis.com/auth/cloud-platform"

# Request an access token that is valid for this many seconds.
$gAuth.ExpireNumSeconds = 3600

# If the application is requesting delegated access:
# The email address of the user for which the application is requesting delegated access,
# then set the email address here. (Otherwise leave it empty.)
$gAuth.SubEmailAddress = ""

# ------------------------------------------------------------------------
# Set the IAT using the date/time from the NIST time server.
$unixTime = $dt.GetAsUnixTime($false)
$("unixTime = " + $unixTime)
$gAuth.Iat = $unixTime

# Connect to www.googleapis.com using TLS (TLS 1.2 is the default.)
# The Chilkat socket object is used so that the connection can be established
# through proxies or an SSH tunnel if desired.
$tlsSock = New-Object Chilkat_9_5_0.Socket
$success = $tlsSock.Connect("www.googleapis.com",443,$true,5000)
if ($success -ne $true) {
    $($tlsSock.LastErrorText)
    exit
}

# Send the request to obtain the access token.
$success = $gAuth.ObtainAccessToken($tlsSock)
if ($success -ne $true) {
    $($gAuth.LastErrorText)
    exit
}

# Examine the access token:
$("Access Token: " + $gAuth.AccessToken)