(Excel) Quickbooks OAuth2 in a Desktop App

Demonstrates how to get a QuickBooks OAuth2 access token from a desktop application or script.

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

' This example is for desktop applicatons (it is not for code that runs on a web server).
' You'll need to add a line (or a few lines of code) to popup a web browser that navigates to a URL.
' This is explained in the comments below.

' This is the way to initially obtain the OAuth2 access token.  Afterwards it can be 
' repeatedly refreshed without user interaction, as shown in this example: Refresh Quickbooks OAuth2 Access Token.

Dim oauth2 As Chilkat.OAuth2
Set oauth2 = Chilkat.NewOAuth2

' QuickBooks OAuth2 allows for an "http://localhost:<portNumber>/" callback URL for sandbox testing,
' but not for production.
' For a desktop app, you must provide a script on your web server to redirect to "http://localhost/<portNumber>"
' It can be written in C#, PHP, or whatever desired.  It must include the query string in the redirection.
' For example, in PHP your script would look like this:

' <?php
'   header( 'Location: http://localhost:3017?' . $_SERVER['QUERY_STRING'] );
' ?>

oauth2.AppCallbackUrl = "https://yourwebserver.com/OAuth2.php"
oauth2.ListenPort = 3017

oauth2.AuthorizationEndpoint = "https://appcenter.intuit.com/connect/oauth2"
oauth2.TokenEndpoint = "https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer"

' Replace these with actual values.
oauth2.ClientId = "QUICKBOOKS-CLIENT-ID"
oauth2.ClientSecret = "QUICKBOOKS-CLIENT-SECRET"
oauth2.UseBasicAuth = True
oauth2.CodeChallenge = False

' Indicate the desired access.  Possible scopes that can appear in the list are:
' com.intuit.quickbooks.accounting:  QuickBooks Online API
' com.intuit.quickbooks.payment:  QuickBooks Payments API
' openid:  OpenID Connect processing
' profile:  user's given and family names
' email:  user's email address
' phone:  user's phone number
' address:  user's physical address
oauth2.Scope = "com.intuit.quickbooks.accounting"

' Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.

url = oauth2.StartAuth()
If (oauth2.LastMethodSuccess <> True) Then
    Debug.Print oauth2.LastErrorText
    Exit Sub
End If

Debug.Print "url = "; url

' 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
' in dBASE: run(false, 'rundll32 url.dll,FileProtocolHandler "' + lcUrl + '"')
' 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 60 seconds.

numMsWaited = 0
Do While (numMsWaited < 60000) And (oauth2.AuthFlowState < 3)
    oauth2.SleepMs 100
    numMsWaited = numMsWaited + 100
Loop

' If there was no response from the browser within 60 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
    Dim success As Boolean
    success = oauth2.Cancel()
    Debug.Print "No response from the browser!"
    Exit Sub
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
    Debug.Print "OAuth2 failed to complete."
    Debug.Print oauth2.FailureInfo
    Exit Sub
End If

If (oauth2.AuthFlowState = 4) Then
    Debug.Print "OAuth2 authorization was denied."
    Debug.Print oauth2.AccessTokenResponse
    Exit Sub
End If

If (oauth2.AuthFlowState <> 3) Then
    Debug.Print "Unexpected AuthFlowState:"; oauth2.AuthFlowState
    Exit Sub
End If

' Save the full JSON access token response to a file.
Dim sbJson As Chilkat.StringBuilder
Set sbJson = Chilkat.NewStringBuilder
success = sbJson.Append(oauth2.AccessTokenResponse)
success = sbJson.WriteFile("qa_data/tokens/qb-access-token.json","utf-8",False)

' The full JSON received looks like this:
' {
'   "expires_in": 3600,
'   "x_refresh_token_expires_in": 8726400,
'   "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
'   "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
'   "token_type": "bearer"
' }

Debug.Print "OAuth2 authorization granted!"
Debug.Print "Access Token = "; oauth2.AccessToken