Introduction

PowerBuilder supports getting secured data from the OAuth 2.0 authorization server. The Bearer access token is supported, and the following grant types are supported:

• Authorization Code
• Implicit Flow
• Client Credentials
• Extension (or Refresh Token)
• Resource Owner Password

This document provides an example on how to set up OAuth 2.0 authorization workflow using the Authorization Code grant type in a PowerBuilder application.

Prerequisties

• PowerBuilder 2019 R2 or above

PowerBuilder 2019 R2 has the WebBrowser control for loading the authorization page to get the authorization code; and also the OAuthClient object for obtaining the access token and the protected resource.

• Demo code (available in oauth_code&token_example.zip)

This is the sample PowerBuilder application. It contains two targets:

The oauth_code application applies the OAuth 2.0 authorization workflow using Authorization Code , which will be explained in more details in this document.

The oauth_token application applies the OAuth 2.0 authorization workflow using Implicit Flow. For supporting instructions, please refer to the Supporting OAuth 2.0 Authorization Server section in Application Techniques in the PowerBuilder documentation.

• Setting up the authorization credential in an OAuth Server.

If you follow the instructions at Appendix: Creating a YouTube Data API to create the authorization credential for accessing Google YouTube data APIs, you will have the following authorization credential information prepared:

• Token URL: https://accounts.google.com/o/oauth2/token
• Client ID: 434849452875-6905f1g9rjiargcnqut06afmnn0b0fp7.apps.googleusercontent.com
• Secret: E1b7RsBxZWKq_yrl-kbfONF5
• Username: Your own user name
• Password: Your own password
• Scope: https://www.googleapis.com/auth/youtube
• Redirect: https://www.appeon.com/callback
• Authorization URL: https://accounts.google.com/o/oauth2/auth
• Resource URL: https://www.googleapis.com/oauth2/v1/tokeninfo

Implementing OAuth 2.0 Authorization

Take the following steps to learn how to implement the Authorization Code grant type (granttype = "authorization_code") in the PowerBuilder application.

Step 1: Open the demo application oauth_code_token in PowerBuilder.

Step 2: Ask the user to specify the authorization code details in the authorization_code tab of the w_oauth_code window.

Step 3: Open the WebBrowser control using OpenWithParm in the Clicked event of the GetToken button, with the authorization URL passed in the OpenWithParm parameter.

ls_Url_code = "https://accounts.google.com/o/oauth2/auth?client_id=" + ls_id + "&redirect_uri=" + ls_redirect +"&scope=" + ls_Scope + "&response_type=code"

OpenWithParm (w_webbrowser, ls_Url_code) //via the WebBrowser control

ls_code = Message.Stringparm

 Step 4: Get the access token using the authorization code via OAuthClient.

ltr_Request.tokenlocation = "https://accounts.google.com/o/oauth2/token"

ltr_Request.Method = "POST"

ltr_Request.granttype = "authorization_code"

ltr_Request.clientid = ls_id

ltr_Request.clientsecret = ls_secret

ltr_Request.ClearParams()

ltr_Request.AppendParam( "grant_type", "authorization_code")

ltr_Request.AppendParam( "client_id", ls_id )

ltr_Request.AppendParam( "client_secret", ls_secret )

ltr_Request.AppendParam( "scope", ls_Scope )

ltr_Request.AppendParam( "code", ls_code )

ltr_Request.AppendParam( "redirect_uri", ls_Redirect )

ltr_Request.ClearHeaders()

ltr_Request.SetHeader("Content-Type", "application/x-www-form-urlencoded")

 

li_rtn = loa_Client.AccessToken( ltr_Request, ltr_Response )

Step 5: Get the resource from the resource URL via the access token.

OAuthRequest loa_Request

ResourceResponse lrr_Response

loa_Request.SetAccessToken (access_token)

loa_Request.Method = "GET"

loa_Request.Url = "https://www.googleapis.com/oauth2/v1/tokeninfo"

li_rtn = ioa_Client.requestresource( loa_Request, lrr_Response )

The complete code example is as below:

String ls_id, ls_secret, ls_Scope, ls_Redirect

String ls_Body, ls_code, ls_Url_code, ls_AccessToken

Integer li_rtn

OAuthClient loa_Client

TokenRequest ltr_Request

TokenResponse ltr_Response

OAuthRequest loa_Request

ResourceResponse lrr_Response

CoderObject lco_Code

Blob lb_data

 

lco_Code = Create CoderObject

loa_Client = Create OAuthClient

 

ls_id = "434849452875-6905f1g9rjiargcnqut06afmnn0b0fp7.apps.googleusercontent.com"

ls_secret = "E1b7RsBxZWKq_yrl-kbfONF5"

ls_Scope = "https://www.googleapis.com/auth/youtube"

ls_Redirect = "https://www.appeon.com/callback"

 

//Step 1: Get the authorization code

ls_Url_code = "https://accounts.google.com/o/oauth2/auth?client_id=" + ls_id + "&redirect_uri=" + ls_Redirect +"&scope=" + ls_Scope + "&response_type=code"

OpenWithParm ( w_webbrowser,ls_Url_code )

ls_code = Message.Stringparm

If Len ( ls_code ) < 1 Then Return

If Pos( ls_code, "code=" ) < 0 Then return

ls_code = Mid ( ls_code, pos(ls_code,"=") + 1)

ls_code = Mid ( ls_code, 1, pos(ls_code,"&") - 1)

lb_data = lco_Code.Urldecode( ls_code)

ls_code = String ( lb_data,EncodingANSI!)

 

//Step 2: Get the RESTful Server token

ltr_Request.tokenlocation = "https://accounts.google.com/o/oauth2/token"

ltr_Request.Method = "POST"

ltr_Request.granttype = "authorization_code"

ltr_Request.clientid = ls_id

ltr_Request.clientsecret = ls_secret

ltr_Request.ClearParams()

ltr_Request.AppendParam( "grant_type","authorization_code")

ltr_Request.AppendParam( "client_id", ls_id )

ltr_Request.AppendParam( "client_secret", ls_secret )

ltr_Request.AppendParam( "scope", ls_Scope )

ltr_Request.AppendParam( "code", ls_code )

ltr_Request.AppendParam( "redirect_uri", ls_Redirect )

ltr_Request.ClearHeaders()

ltr_Request.SetHeader("Content-Type","application/x-www-form-urlencoded")

 

li_rtn = loa_Client.AccessToken( ltr_Request, ltr_Response )

If li_rtn = 1 Then

 ls_AccessToken = ltr_Response.GetAccessToken ( )

 //Step 3: Get the RESTful Server resource

 If Len(ls_AccessToken) > 0 Then

  loa_Request.SetAccessToken (ls_AccessToken)

  loa_Request.Method = "GET"

  loa_Request.Url = "https://www.googleapis.com/oauth2/v1/tokeninfo"

  li_rtn = loa_Client.requestresource( loa_Request, lrr_Response )

  If li_rtn = 1 Then

   lrr_Response.GetBody(ls_Body)

   MessageBox ( "Tips", ls_Body )

  End If

 

 End If

End If

Appendix: Creating a YouTube Data API

The following steps demonstrate how to create a YouTube Data API which can be used later to implement the Google OAuth server authorization code in the PowerBuilder application.

1.  Visit https://developers.google.com and select Products -> YouTube.

2.  Select Guides, and then select YouTube Data API (v3).

3.  Read the Overview section and follow its instructions to access the API Console.

4.  From Google APIs, create a new project or select an existing one.

5.  In OAuth consent screen for the project, set Application type to Public, fill in Application name and then click Save.

6.  Select Create Credentials -> OAuth client ID, and then set Application type to Web Application and fill in Name.

You will see Client ID and Client Secret when creation is successful. Save your Client ID and Client Secret for use later.