(Visual Basic 6.0) Microsoft Graph OAuth2 Client Credentials Grant Flow

Demonstrates how to get a Microsoft Graph access token using the Client Credentials Grant Flow.

You can use the OAuth 2.0 client credentials grant specified in RFC 6749, sometimes called two-legged OAuth, to access web-hosted resources by using the identity of an application. This type of grant is commonly used for server-to-server interactions that must run in the background, without immediate interaction with a user. These types of applications are often referred to as daemons or service accounts.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow

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

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

Dim http As New ChilkatHttp

Dim req As New ChilkatHttpRequest
req.AddParam "client_secret","CLIENT_SECRET"
req.AddParam "client_id","CLIENT_ID"
' Don't know if the scopes valid for the client credentials grant are different than the scopes for the 3-legged Authorization Code Grant...
req.AddParam "scope","https://graph.microsoft.com/.default"
req.AddParam "grant_type","client_credentials"

' Use your own tenant ID, for example 4d8fdd66-66d1-43b0-ae5c-e31b4b7de5cd
Dim url As String
url = "https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token"
Dim resp As ChilkatHttpResponse
Set resp = http.PostUrlEncoded(url,req)
If (http.LastMethodSuccess <> 1) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

Dim statusCode As Long
statusCode = resp.StatusCode
Debug.Print "Response status code = " & statusCode

Dim json As New ChilkatJsonObject
success = json.Load(resp.BodyStr)

json.EmitCompact = 0
Debug.Print json.Emit()

' Sample successful output:

' {
'   "token_type": "Bearer",
'   "expires_in": 3599,
'   "ext_expires_in": 3599,
'   "access_token": "eyJ0eX...K0jOERg"
' }

If (statusCode = 200) Then
    success = json.WriteFile("qa_data/tokens/msGraphClientCredentialsToken.json")
    Debug.Print "Success."
Else
    Debug.Print "Failed."
End If