(PowerShell) Google OAuth2 Access Token

Demonstrates how to get a Google OAuth2 access token from a desktop application or script.

Note: This example requires Chilkat v10.1.2 or later.

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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

# For Google OAuth2, set the listen port equal to the port used
# in the Authorized Redirect URL for the Client ID.
# For example, in this case the Authorized Redirect URL would be http://localhost:55568/
# Your app should choose a port not likely not used by another application.
$oauth2.ListenPort = 55568

$oauth2.AuthorizationEndpoint = "https://accounts.google.com/o/oauth2/v2/auth"
$oauth2.TokenEndpoint = "https://www.googleapis.com/oauth2/v4/token"

# Replace this with your actual client ID.
$oauth2.ClientId = "GOOGLE-CLIENT-ID"

# This is the scope for Google Drive.
# See https://developers.google.com/identity/protocols/googlescopes
# Add the scopes that you need.
$oauth2.Scope = "https://www.googleapis.com/auth/drive"

# 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)
$sbJson.WriteFile("qa_data/tokens/_googleDrive.json","utf-8",$false)

# The saved JSON response looks like this:

# 	{
# 	 "access_token": "ya39.Ci-XA_C5bGgRDC3UaD-h0_NeL-DVIQnI2gHtBBBHkZzrwlARkwX6R3O0PCDEzRlfaQ",
# 	 "token_type": "Bearer",
# 	 "expires_in": 3600,
# 	 "refresh_token": "1/r_2c_7jddspcdfesrrfKqfXtqo08D6Q-gUU0DsdfVMsx0c"
# 	}
# 
$("OAuth2 authorization granted!")
$("Access Token = " + $oauth2.AccessToken)

# Here is an example showing how to define your OAuth 2.0 Credential in the Google Cloud Console
# Note: Even though your application is technically not a web app, you should still select "Web Application"
# because the Redirect URI is going to http://localhost:55568/ where Chilkat will receive it in a background thread.

#