(PowerBuilder) Google Cloud Storage OAuth2 Access Token (Authorization Code Flow)

Gets the initial OAuth2 access token with the scope needed for Google Cloud Storage operations. This uses the authorization code flow and is NOT for a Google service account.

Your Google App client ID should be created as shown below. Set the application type as a "Web Application" even though it's not really a web application. The reason is that when you call StartAuth, Chilkat runs a background thread to act as a temporary web browser to receive the redirect from your local web browser.

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

integer li_rc
oleobject loo_Oauth2
integer li_Success
string ls_Url
integer li_NumMsWaited
oleobject loo_SbJson

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

loo_Oauth2 = create oleobject
// Use "Chilkat_9_5_0.OAuth2" for versions of Chilkat < 10.0.0
li_rc = loo_Oauth2.ConnectToNewObject("Chilkat.OAuth2")
if li_rc < 0 then
    destroy loo_Oauth2
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// 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:3017/
// Your app should choose a port not likely not used by any other application.
loo_Oauth2.ListenPort = 3017

loo_Oauth2.AuthorizationEndpoint = "https://accounts.google.com/o/oauth2/v2/auth"
loo_Oauth2.TokenEndpoint = "https://www.googleapis.com/oauth2/v4/token"

// Replace these with actual values.
loo_Oauth2.ClientId = "GOOGLE-CLIENT-ID"
loo_Oauth2.ClientSecret = "GOOGLE-CLIENT-SECRET"

loo_Oauth2.CodeChallenge = 1
loo_Oauth2.CodeChallengeMethod = "S256"

loo_Oauth2.Scope = "https://www.googleapis.com/auth/devstorage.full_control"

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
ls_Url = loo_Oauth2.StartAuth()
if loo_Oauth2.LastMethodSuccess <> 1 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_Oauth2
    return
end if

// At this point, your application should load the URL in a browser.
// For example, 
// in C#: System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The QuickBooks account owner would interactively accept or deny the authorization request.

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...

// Now wait for the authorization.
// We'll wait for a max of 30 seconds.
li_NumMsWaited = 0
do while (li_NumMsWaited < 30000) AND (loo_Oauth2.AuthFlowState < 3)
    loo_Oauth2.SleepMs(100)
    li_NumMsWaited = li_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 loo_Oauth2.AuthFlowState < 3 then
    loo_Oauth2.Cancel()
    Write-Debug "No response from the browser!"
    destroy loo_Oauth2
    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 loo_Oauth2.AuthFlowState = 5 then
    Write-Debug "OAuth2 failed to complete."
    Write-Debug loo_Oauth2.FailureInfo
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState = 4 then
    Write-Debug "OAuth2 authorization was denied."
    Write-Debug loo_Oauth2.AccessTokenResponse
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState <> 3 then
    Write-Debug "Unexpected AuthFlowState:" + string(loo_Oauth2.AuthFlowState)
    destroy loo_Oauth2
    return
end if

// Save the full JSON access token response to a file.
loo_SbJson = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbJson.ConnectToNewObject("Chilkat.StringBuilder")

loo_SbJson.Append(loo_Oauth2.AccessTokenResponse)
loo_SbJson.WriteFile("qa_data/tokens/googleCloudStorage.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"
// 	}
// 
Write-Debug "OAuth2 authorization granted!"
Write-Debug "Access Token = " + loo_Oauth2.AccessToken


destroy loo_Oauth2
destroy loo_SbJson