B4X

Get a Google People API OAuth2 Access Token

See more Google People Examples

Demonstrates how to get a Google People OAuth2 access token from a desktop application or script. B4X

Dim success As Boolean = False

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

Dim oauth2 As ChilkatOAuth2
oauth2.Initialize("oauth2")

'  For Google OAuth2, set the ListenPort equal to the port specified in the authorized callback URI for the ClientID.
'  See http://cknotes.com/setup-google-account-for-google-drive-api-walkthrough/
oauth2.ListenPort = 3017

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

'  Replace these with actual values.
oauth2.ClientId = "GOOGLE-CLIENT-ID"
oauth2.ClientSecret = "GOOGLE-CLIENT-SECRET"

oauth2.CodeChallenge = True
oauth2.CodeChallengeMethod = "S256"

'  See Google People API Scopes for more scopes.
oauth2.Scope = "profile https://www.googleapis.com/auth/contacts https://www.googleapis.com/auth/contacts.other.readonly https://www.googleapis.com/auth/directory.readonly"

'  Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
Dim url As String = oauth2.StartAuth
If oauth2.LastMethodSuccess = False Then
    Log(oauth2.LastErrorText)
    Return
End If


'  Launch the system's default browser navigated to the URL.
success = oauth2.LaunchBrowser(url)
If success = False Then
    Log(oauth2.LastErrorText)
    Return
End If


'  Now wait for the authorization.
'  We'll wait for a max of 30 seconds.
Dim numMsWaited As Int = 0
Do While (numMsWaited < 30000) And (oauth2.AuthFlowState < 3)
    oauth2.SleepMs(100)
    numMsWaited = numMsWaited + 100
Loop

'  If there was no response from the browser within 30 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 < 3 Then
    oauth2.Cancel
    Log("No response from the browser!")
    Return
End If


'  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 = 5 Then
    Log("OAuth2 failed to complete.")
    Log(oauth2.FailureInfo)
    Return
End If


If oauth2.AuthFlowState = 4 Then
    Log("OAuth2 authorization was denied.")
    Log(oauth2.AccessTokenResponse)
    Return
End If


If oauth2.AuthFlowState <> 3 Then
    Log("Unexpected AuthFlowState:" & oauth2.AuthFlowState)
    Return
End If


'  Save the full JSON access token response to a file.
Dim sbJson As ChilkatStringBuilder
sbJson.Initialize
sbJson.Append(oauth2.AccessTokenResponse)
sbJson.WriteFile("qa_data/tokens/googlePeople.json", "utf-8", False)

'  The saved JSON response looks like this:

'  {
'    "access_token": "ya29.a0AfH6S ... LAZYFUkf0",
'    "expires_in": 3599,
'    "refresh_token": "1//0fL_Ov ... ee0",
'    "scope": "https://www.googleapis.com/auth/contacts",
'    "token_type": "Bearer"
'  }

Log("OAuth2 authorization granted!")
Log("Access Token = " & oauth2.AccessToken)