|  | (PowerShell) Datev OAuth2 Access TokenDemonstrates how to get a Datev OAuth2 access token from a desktop application or script.Note: This example requires Chilkat v10.1.3 or greater. 
 Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"
# To further clarify, see OAuth 2.0 Authorization Flow
$oauth2 = New-Object Chilkat.OAuth2
# Your Datev app should use "http://localhost" (no trailing forward slash) for the redirect URL.
$oauth2.ListenPort = 3017
#  $oauth2.AuthorizationEndpoint = "https://login.datev.de/openidsandbox/authorize"
$oauth2.TokenEndpoint = "https://sandbox-api.datev.de/token"
# Replace this with your actual client ID.
$oauth2.ClientId = "DATEV_CLIENT_ID"
$oauth2.ClientSecret = "DATEV_CLIENT_SECRET"
$oauth2.CodeChallenge = $true
$oauth2.CodeChallengeMethod = "S256"
$oauth2.Scope = "openid profile email datev:accounting:clients accounting:documents datev:accounting:extf-files-import"
# Begin the OAuth2 authorization code 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 interactive user to grant permission in the interactive browser session.
# We'll wait for a max of 90 seconds.
$numMsWaited = 0
while (($numMsWaited -lt 90000) -and ($oauth2.AuthFlowState -lt 3)) {
    $oauth2.SleepMs(100)
    $numMsWaited = $numMsWaited + 100
}
# If there was no response from the browser within 90 seconds, then 
# the AuthFlowState will be equal to 1 or 2.
# 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
# 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
# In that case, cancel the background task started in the call to StartAuth.
if ($oauth2.AuthFlowState -lt 3) {
    $oauth2.Cancel()
    $("No response from the browser!")
    exit
}
# Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
# The possible AuthFlowState values are:
# 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
# 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
# 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if ($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
}
# Save the full JSON access token response to a file.
$sbJson = New-Object Chilkat.StringBuilder
$sbJson.Append($oauth2.AccessTokenResponse)
$sbJson.WriteFile("qa_data/tokens/datev.json","utf-8",$false)
# The saved JSON response looks like this:
# {
# 	"refresh_token": "ZDA5Y .... FFhTXc9",
# 	"refresh_token_expires_in": 39600,
# 	"id_token": "eyJ .... Q9w",
# 	"access_token": "MTM .... 1UDA9",
# 	"token_type": "bearer",
# 	"expires_in": 900		
# }
$("OAuth2 authorization granted!")
$("Access Token = " + $oauth2.AccessToken) |