(PowerShell) Azure AD Service-to-service access token request

Send an Azure AD service-to-service token request to get an access token using a shared secret.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v1-oauth2-client-creds-grant-flow#service-to-service-access-token-request

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.

$http = New-Object Chilkat.Http

# To see the exact HTTP request sent and the response, set the SessionLogFilename property:
$http.SessionLogFilename = "qa_output/chilkatHttpLog.txt"

$req = New-Object Chilkat.HttpRequest

# Set the following request params:
# grant_type 	required 	Specifies the requested grant type. In a Client Credentials Grant flow, the value must be client_credentials.
# 
# client_id 	required 	Specifies the Azure AD client id of the calling web service. 
#     To find the calling application's client ID, in the Azure portal, click Azure Active Directory, click App registrations, click the application. 
#     The client_id is the Application ID
# 
# client_secret 	required 	Enter a key registered for the calling web service or daemon application in Azure AD. 
#     To create a key, in the Azure portal, click Azure Active Directory, click App registrations, click the application, click Settings, click Keys, and add a Key.
#     URL-encode this secret when providing it.
# 
# resource 	required 	Enter the App ID URI of the receiving web service. To find the App ID URI, in the Azure portal, click Azure Active Directory, 
#     click App registrations, click the service application, and then click Settings and Properties.

$req.AddParam("grant_type","client_credentials")
$req.AddParam("client_id","MY_CLIENT_ID")
$req.AddParam("client_secret","MY_CLIENT_SECRET")
$req.AddParam("resource","https://service.contoso.com/")

# The URL passed to PostUrlEncoded has this form:   https://login.microsoftonline.com/<tenant_id>/oauth2/token
$resp = $http.PostUrlEncoded("https://login.microsoftonline.com/<tenant_id>/oauth2/token",$req)
if ($http.LastMethodSuccess -eq $false) {
    $($http.LastErrorText)
    exit
}

$respStatusCode = $resp.StatusCode
$("Response Status Code = " + $respStatusCode)

$json = New-Object Chilkat.JsonObject
$json.EmitCompact = $false
$json.Load($resp.BodyStr)
$("Response JSON:")
$($json.Emit())

if ($respStatusCode -ge 400) {
    $("Response Header:")
    $($resp.Header)
    $("Failed.")

    exit
}

# Sample response:

# {
#   "token_type": "Bearer",
#   "expires_in": "3599",
#   "ext_expires_in": "3599",
#   "expires_on": "1570059833",
#   "not_before": "1570055933",
#   "resource": "https://adminchilkatsoft.onmicrosoft.com/eb1b8ced-76b7-4845-aec5-d3e91776e345",
#   "access_token": "eyJ0eXAiO ... pmgw"
# }

# To get the items from the JSON....
$token_type = $json.StringOf("token_type")
$expires_in = $json.StringOf("expires_in")
$ext_expires_in = $json.StringOf("ext_expires_in")
$expires_on = $json.StringOf("expires_on")
$not_before = $json.StringOf("not_before")
$resource = $json.StringOf("resource")
$access_token = $json.StringOf("access_token")