(Excel) Adobe Sign OAuth2 Access Token

Demonstrates how to get an Adobe Sign OAuth2 access token from a desktop application or script.

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

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

' The Adobe Sign OAuth2 requires an "https" callback URL.  This means the "http://localhost:<portNumber>/" is not possible.
' 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://secure.na2.echosign.com/public/oauth"
oauth2.TokenEndpoint = "https://api.na2.echosign.com/oauth/token"

' Replace these with actual values.
oauth2.ClientId = "MY_CLIENT_ID"
oauth2.ClientSecret = "MY_CLIENT_SECRET"
oauth2.CodeChallenge = False

' Indicate the desired access by listing scopes.
oauth2.Scope = "user_read agreement_read workflow_read"

' 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        
' The Adobe Sign 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
    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/adobe-sign-access-token.json","utf-8",False)

' The full JSON received looks like this:
' {
'   "access_token": "3AAABL ... YCpUu",
'   "refresh_token": "3AAABL ... tpDs0*",
'   "token_type": "Bearer",
'   "expires_in": 3600
' }

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