(PowerShell) Get Google Cloud Storage Access Token using Service Account JSON Private Key

Demonstrates how to get a Google Cloud Storage access token using a JSON service account private key. Obtaining an access token for a service account requires no user interaction (it does not require a browser, nor callback URI's, etc.).

When an access token expires, an application can be (and should be) designed to automatically fetch a new access token.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

# First load the JSON key into a string.
$fac = New-Object Chilkat.FileAccess
$jsonKey = $fac.ReadEntireTextFile("qa_data/googleApi/ChilkatCloud-13a07a2e8b3f.json","utf-8")
if ($fac.LastMethodSuccess -ne $true) {
    $($fac.LastErrorText)
    exit
}

# A JSON private key should look something 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.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 = ""

# 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.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)

# We're going to save this access token to a file to be used
# by other examples.
$sbToken = New-Object Chilkat.StringBuilder
$sbToken.Append($gAuth.AccessToken)
$sbToken.WriteFile("qa_data/tokens/googleCloudStorageAccessToken.txt","utf-8",$false)