(Visual FoxPro) Authorization Code Flow with PKCE for Native Apps

Demonstrates the authorization code flow with Proof Key for Code Exchange (PKCE) for native apps. In Okta, your app should be defined as shown:

For more information, see https://developer.okta.com/docs/guides/implement-auth-code-pkce/use-flow/

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

LOCAL loOauth2
LOCAL lnSuccess
LOCAL lcUrl
LOCAL lnNumMsWaited
LOCAL loJson
LOCAL loFac

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.OAuth2')
loOauth2 = CreateObject('Chilkat.OAuth2')

* This should be the port in the Login redirect URI for your app.  
* Your app's Login redirect URI should be "http://localhost:3017/" if the port number is 3017.
loOauth2.ListenPort = 3017

loOauth2.AuthorizationEndpoint = "https://{yourOktaDomain}/oauth2/default/v1/authorize"
loOauth2.TokenEndpoint = "https://{yourOktaDomain}/oauth2/default/v1/token"

* Replace these with actual values.
loOauth2.ClientId = "OKTA_CLIENT_ID"
loOauth2.ClientSecret = "OKTA_CLIENT_SECRET"

loOauth2.CodeChallenge = 1
loOauth2.IncludeNonce = 1

* Make sure to include "offline_access" to get a refresh token included in the final JSON response.
* Add any additional needed scopes separated by space chars.
loOauth2.Scope = "openid offline_access"

* Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
lcUrl = loOauth2.StartAuth()
IF (loOauth2.LastMethodSuccess <> 1) THEN
    ? loOauth2.LastErrorText
    RELEASE loOauth2
    CANCEL
ENDIF

? "URL to load in browser: " + lcUrl

* 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 Microsoft 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 60 seconds.
lnNumMsWaited = 0
DO WHILE (lnNumMsWaited < 60000) AND (loOauth2.AuthFlowState < 3)
    loOauth2.SleepMs(100)
    lnNumMsWaited = lnNumMsWaited + 100
ENDDO

* 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 (loOauth2.AuthFlowState < 3) THEN
    loOauth2.Cancel()
    ? "No response from the browser!"
    RELEASE loOauth2
    CANCEL
ENDIF

* 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 (loOauth2.AuthFlowState = 5) THEN
    ? "OAuth2 failed to complete."
    ? loOauth2.FailureInfo
    RELEASE loOauth2
    CANCEL
ENDIF

IF (loOauth2.AuthFlowState = 4) THEN
    ? "OAuth2 authorization was denied."
    ? loOauth2.AccessTokenResponse
    RELEASE loOauth2
    CANCEL
ENDIF

IF (loOauth2.AuthFlowState <> 3) THEN
    ? "Unexpected AuthFlowState:" + STR(loOauth2.AuthFlowState)
    RELEASE loOauth2
    CANCEL
ENDIF

? "OAuth2 authorization granted!"
? "Access Token = " + loOauth2.AccessToken

* Get the full JSON response:
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.Load(loOauth2.AccessTokenResponse)
loJson.EmitCompact = 0
? loJson.Emit()

* The JSON response looks like this:

* {
*   "access_token": "eyJraWQi ... Kn4IiEfOw",
*   "token_type": "Bearer",
*   "expires_in": 3600,
*   "scope": "offline_access openid",
*   "refresh_token": "0jCqotuuUegdjNzB9uuSsfGM2Cu5HnCHUxoJ0yhZ4rs",
*   "id_token": "eyJraWQiO ... 09WGEq3dTRmQF86PzJg"
* }

* Save the JSON to a file for future requests.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.FileAccess')
loFac = CreateObject('Chilkat.FileAccess')
loFac.WriteEntireTextFile("qa_data/tokens/okta.json",loJson.Emit(),"utf-8",0)

RELEASE loOauth2
RELEASE loJson
RELEASE loFac