(Visual Basic 6.0) Constant Contact (v3) OAuth2 Access Token

Gets an OAuth2 access token for ConstantContact.

For more information, see https://v3.developer.constantcontact.com/api_guide/server_flow.html

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

Dim success As Long
success = 0

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

Dim oauth2 As New ChilkatOAuth2

' This should be the port in the localhost callback URL for your app.  
' The callback URL would look like "http://localhost:3017/" if the port number is 3017.
' Make sure when defining your application (i.e. "My Applications" at  https://app.constantcontact.com/pages/dma/portal/)
' that the Redirect URI is exactly this:  "http://localhost:3017/".   You may use any port number as long as it agrees
' with the ListenPort here.  It is important to use "http" and not "https" in the callback URI.  The trailing "/" is also important.
oauth2.ListenPort = 3017

oauth2.AuthorizationEndpoint = "https://api.cc.email/v3/idfed"
oauth2.TokenEndpoint = "https://idfed.constantcontact.com/as/token.oauth2"

' Replace these with actual values.
oauth2.ClientId = "CLIENT_KEY"
oauth2.ClientSecret = "CLIENT_SECRET"

' Add one or more SPACE separated scopes
oauth2.Scope = "account_read account_update contact_data campaign_data"

' Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
Dim url As String
url = oauth2.StartAuth()
If (oauth2.LastMethodSuccess = 0) Then
    Debug.Print oauth2.LastErrorText
    Exit Sub
End If

Debug.Print url

' Launch the system's default browser navigated to the URL.
success = oauth2.LaunchBrowser(url)
If (success = 0) Then
    Debug.Print oauth2.LastErrorText
    Exit Sub
End If

' Now wait for the authorization.
' We'll wait for a max of 30 seconds.
Dim numMsWaited As Long
numMsWaited = 0
Do While (numMsWaited < 30000) And (oauth2.AuthFlowState < 3)
    oauth2.SleepMs 100
    numMsWaited = 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 (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

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

' Get the full JSON response:
Dim json As New ChilkatJsonObject
success = json.Load(oauth2.AccessTokenResponse)
json.EmitCompact = 0

' The JSON response looks like this:

' {
'   "access_token": "aEr4czHReESHUGcc2LRknzsMxUbW",
'   "refresh_token": "s2qH27ikM7r3Ia0LrZGDOIgKw0bubUotBdJ7fTtc7y",
'   "token_type": "Bearer"
' }

Debug.Print json.Emit()

' Save the JSON to a file for future requests.
Dim fac As New CkFileAccess
success = fac.WriteEntireTextFile("qa_data/tokens/constantContact.json",json.Emit(),"utf-8",0)