(PowerShell) Get OAuth2 Access Token for Azure Registered App

Demonstrates how to get OAuth2 access token for an Azure Registered App from a desktop application or script. This example demonstrates the OAuth2 authorization flow.

This example requires Chilkat v10.1.2 or greater.

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

# To further clarify, see OAuth 2.0 Authorization Flow

$oauth2 = New-Object Chilkat.OAuth2

# This should be the port in the localhost callback URL for your app.  
# The callback URL would look like "http://localhost:3017/" if the port number is 3017.
$oauth2.ListenPort = 3017

# ----------------------------------------------------------------------------------------------------------
# The screenshot at the bottom of this page shows how we created the Azure App Registration for this example.
# ----------------------------------------------------------------------------------------------------------

# Note: The endpoint depends on the Azure App Registration.
# See How to Choose the Correct Endpoints for your Azure App Registration
$oauth2.AuthorizationEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize"
$oauth2.TokenEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token"

# Replace these with actual values.
$oauth2.ClientId = "CLIENT_ID"

# This is for Require Proof Key for Code Exchange (PKCE)
# See OAuth2 PKCE Explained
$oauth2.CodeChallenge = $true
$oauth2.CodeChallengeMethod = "S256"

# Provide a SPACE separated list of scopes.
# See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

# Important: To get a refresh token in the final response, ask for "offline_access" scope
$oauth2.Scope = "openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite"

# Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
$url = $oauth2.StartAuth()
if ($oauth2.LastMethodSuccess -ne $true) {
    $($oauth2.LastErrorText)
    exit
}

# Launch the default browser on the system and navigate to the url.
# The LaunchBrowser method was added in Chilkat v10.1.2.
$success = $oauth2.LaunchBrowser($url)
if ($success -eq $false) {
    $($oauth2.LastErrorText)
    exit
}

# Wait for the user to approve or deny authorization in the browser.
$numMsWaited = 0
while (($numMsWaited -lt 90000) -and ($oauth2.AuthFlowState -lt 3)) {
    $oauth2.SleepMs(100)
    $numMsWaited = $numMsWaited + 100
}

# If the browser does not respond within the specified time, AuthFlowState will be:
# 
# 1: Waiting for Redirect � The OAuth2 background thread is waiting for the browser's redirect request.
# 2: Waiting for Final Response � The thread is awaiting the final access token response.
# In either case, cancel the background task initiated by StartAuth.

if ($oauth2.AuthFlowState -lt 3) {
    $oauth2.Cancel()
    $("No response from the browser!")
    exit
}

# Check AuthFlowState to determine if authorization was granted, denied, or failed:
# 
# 3: Success � OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
# 4: Access Denied � OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
# 5: Failure � OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if ($oauth2.AuthFlowState -eq 5) {
    $("OAuth2 failed to complete.")
    $($oauth2.FailureInfo)
    exit
}

if ($oauth2.AuthFlowState -eq 4) {
    $("OAuth2 authorization was denied.")
    $($oauth2.AccessTokenResponse)
    exit
}

if ($oauth2.AuthFlowState -ne 3) {
    $("Unexpected AuthFlowState:" + $oauth2.AuthFlowState)
    exit
}

$("OAuth2 authorization granted!")
$("Access Token = " + $oauth2.AccessToken)

# When the token is near expiration, your app can refresh as shown here:
# Refresh Expiring OAuth2 Access Token for Azure Registered App

# Get the full JSON response:
$json = New-Object Chilkat.JsonObject
$json.Load($oauth2.AccessTokenResponse)
$json.EmitCompact = $false

# The JSON response looks like this:

# {
#   "token_type": "Bearer",
#   "scope": "User.Read Mail.ReadWrite Mail.Send",
#   "expires_in": 3600,
#   "ext_expires_in": 0,
#   "access_token": "EwBAA8l6B...",
#   "refresh_token": "MCRMdbe...",
#   "id_token": "eyJ0eXA..."
# }

# If an "expires_on" member does not exist, then add the JSON member by
# getting the current system date/time and adding the "expires_in" seconds.
# This way we'll know when the token expires.
if ($json.HasMember("expires_on") -ne $true) {
    $dtExpire = New-Object Chilkat.CkDateTime
    $dtExpire.SetFromCurrentSystemTime()
    $dtExpire.AddSeconds($json.IntOf("expires_in"))
    $json.AppendString("expires_on",$dtExpire.GetAsUnixTimeStr($false))
}

$($json.Emit())

# Save the JSON to a file for future requests.
$fac = New-Object Chilkat.FileAccess
$fac.WriteEntireTextFile("qa_data/tokens/_myAzureApp.json",$json.Emit(),"utf-8",$false)

# This is a screenshot of how we created the Azure App for this example:
#