(SQL Server) Get GMail SMTP OAuth2 Access Token for Desktop App

See more OAuth2 Examples

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- To further clarify, see OAuth 2.0 Authorization Flow

    DECLARE @oauth2 int
    -- Use "Chilkat_9_5_0.OAuth2" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.OAuth2', @oauth2 OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- 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 any other application.
    EXEC sp_OASetProperty @oauth2, 'ListenPort', 55568

    EXEC sp_OASetProperty @oauth2, 'AuthorizationEndpoint', 'https://accounts.google.com/o/oauth2/v2/auth'
    EXEC sp_OASetProperty @oauth2, 'TokenEndpoint', 'https://www.googleapis.com/oauth2/v4/token'

    -- Replace these with actual values.
    EXEC sp_OASetProperty @oauth2, 'ClientId', 'GOOGLE-CLIENT-ID'
    EXEC sp_OASetProperty @oauth2, 'ClientSecret', 'GOOGLE-CLIENT-SECRET'

    -- To use Gmail's OAuth2 for sending emails via the SMTP protocol, you need to request the https://mail.google.com/ scope. 
    -- See About GMail SMTP OAuth2 Scopes
    EXEC sp_OASetProperty @oauth2, 'Scope', 'https://mail.google.com/'

    -- Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
    DECLARE @url nvarchar(4000)
    EXEC sp_OAMethod @oauth2, 'StartAuth', @url OUT
    EXEC sp_OAGetProperty @oauth2, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @oauth2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    -- Launch the default browser on the system and navigate to the url.
    -- The LaunchBrowser method was added in Chilkat v10.1.2.
    DECLARE @success int
    EXEC sp_OAMethod @oauth2, 'LaunchBrowser', @success OUT, @url
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @oauth2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    -- Wait for the user to approve or deny authorization in the browser.
    DECLARE @numMsWaited int
    SELECT @numMsWaited = 0
    EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
    WHILE (@numMsWaited < 90000) and (@iTmp0 < 3)
      BEGIN
        EXEC sp_OAMethod @oauth2, 'SleepMs', NULL, 100
        SELECT @numMsWaited = @numMsWaited + 100
      END

    -- 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.

    EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
    IF @iTmp0 < 3
      BEGIN
        EXEC sp_OAMethod @oauth2, 'Cancel', @success OUT

        PRINT 'No response from the browser!'
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    -- 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.

    EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
    IF @iTmp0 = 5
      BEGIN

        PRINT 'OAuth2 failed to complete.'
        EXEC sp_OAGetProperty @oauth2, 'FailureInfo', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
    IF @iTmp0 = 4
      BEGIN

        PRINT 'OAuth2 authorization was denied.'
        EXEC sp_OAGetProperty @oauth2, 'AccessTokenResponse', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
    IF @iTmp0 <> 3
      BEGIN

        EXEC sp_OAGetProperty @oauth2, 'AuthFlowState', @iTmp0 OUT
        PRINT 'Unexpected AuthFlowState:' + @iTmp0
        EXEC @hr = sp_OADestroy @oauth2
        RETURN
      END

    -- Save the full JSON access token response to a file.
    DECLARE @sbJson int
    -- Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbJson OUT

    EXEC sp_OAGetProperty @oauth2, 'AccessTokenResponse', @sTmp0 OUT
    EXEC sp_OAMethod @sbJson, 'Append', @success OUT, @sTmp0
    EXEC sp_OAMethod @sbJson, 'WriteFile', @success OUT, 'qa_data/tokens/_gmailSmtp.json', 'utf-8', 0

    -- 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"
    -- 	}
    -- 

    PRINT 'OAuth2 authorization granted!'

    EXEC sp_OAGetProperty @oauth2, 'AccessToken', @sTmp0 OUT
    PRINT 'Access Token = ' + @sTmp0

    EXEC @hr = sp_OADestroy @oauth2
    EXEC @hr = sp_OADestroy @sbJson


END
GO