(VB.NET) Decode Microsoft Graph ID Token

Demonstrates how to decode a Microsoft Graph ID token.

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


' In a previous example, we obtained a Microsoft Graph OAuth2 access token.
' This example loads the JSON saved from the previous example and decodes the id_token.

' Our Microsoft Graph OAuth2 token looks like this:

' {
'   "token_type": "Bearer",
'   "scope": "openid profile User.ReadWrite Mail.ReadWrite Mail.Send Files.ReadWrite User.Read Calendars.ReadWrite Group.ReadWrite.All",
'   "expires_in": 3600,
'   "ext_expires_in": 3600,
'   "access_token": "EwCQA8l6...0HhMKYwC",
'   "refresh_token": "MCWulIvzi2yD0S...igEFn51mqcByhZtAJg",
'   "id_token": "eyJ0eXAiOiJKV1...Q7lRDaR-7A",
'   "expires_on": "1562862714"
' }

Dim jsonToken As New Chilkat.JsonObject
Dim success As Boolean = jsonToken.LoadFile("qa_data/tokens/microsoftGraph.json")
If (success = False) Then
    Debug.WriteLine("Failed to load the JSON file...")
    Exit Sub
End If


' Use Chilkat's JWT API to examine the id_token..
Dim jwt As New Chilkat.Jwt
Dim idToken As String = jsonToken.StringOf("id_token")

' Extract the JOSE header..
Dim jose As String = jwt.GetHeader(idToken)

Dim jsonHeader As New Chilkat.JsonObject
jsonHeader.Load(jose)
jsonHeader.EmitCompact = False
Debug.WriteLine(jsonHeader.Emit())

' The JOSE header looks like this:

' {
'   "typ": "JWT",
'   "alg": "RS256",
'   "kid": "1LTMzakihiRla_8z2BEJVXeWMqo"
' }


Dim claims As String = jwt.GetPayload(idToken)

Dim jsonClaims As New Chilkat.JsonObject
jsonClaims.Load(claims)
jsonClaims.EmitCompact = False
Debug.WriteLine(jsonClaims.Emit())

' The claims look like this:

' {
'   "ver": "2.0",
'   "iss": "https://login.microsoftonline.com/9188040d-6c67-4c5b-b112-36a304b66dad/v2.0",
'   "sub": "AAAAAAAAAAAAAAAAAAAAAHJFryd6Gydo-XtTd1nhUNQ",
'   "aud": "18c456bd-db75-43fe-9724-9e5d821c68ff",
'   "exp": 1562945513,
'   "iat": 1562858813,
'   "nbf": 1562858813,
'   "name": "Matt Chilkat",
'   "preferred_username": "matt@example.com",
'   "oid": "00000000-0000-0000-3a33-fceb9b74cc15",
'   "tid": "9188040d-6c67-4c5b-b112-36a304b66dad",
'   "aio": "DfibJqKnWC1c0FS6G ... W6pvTrQuYzyq16ghY$"
' }
' 


' Use this online tool to generate parsing code from sample JSON: 
' Generate Parsing Code from JSON

' Get each of the claims..
Dim ver As String = jsonClaims.StringOf("ver")
Dim iss As String = jsonClaims.StringOf("iss")
Dim s_sub As String = jsonClaims.StringOf("sub")
Dim aud As String = jsonClaims.StringOf("aud")
Dim exp As Integer = jsonClaims.IntOf("exp")
Dim iat As Integer = jsonClaims.IntOf("iat")
Dim nbf As Integer = jsonClaims.IntOf("nbf")
Dim name As String = jsonClaims.StringOf("name")
Dim preferred_username As String = jsonClaims.StringOf("preferred_username")
Dim oid As String = jsonClaims.StringOf("oid")
Dim tid As String = jsonClaims.StringOf("tid")
Dim aio As String = jsonClaims.StringOf("aio")