(Excel) 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 Chilkat.JsonObject
Set jsonToken = Chilkat.NewJsonObject

success = jsonToken.LoadFile("qa_data/tokens/microsoftGraph.json")
If (success = False) Then
    Debug.Print "Failed to load the JSON file..."
    Exit Sub
End If

' Use Chilkat's JWT API to examine the id_token..
Dim jwt As Chilkat.Jwt
Set jwt = Chilkat.NewJwt

idToken = jsonToken.StringOf("id_token")

' Extract the JOSE header..

jose = jwt.GetHeader(idToken)

Dim jsonHeader As Chilkat.JsonObject
Set jsonHeader = Chilkat.NewJsonObject
success = jsonHeader.Load(jose)
jsonHeader.EmitCompact = False
Debug.Print jsonHeader.Emit()

' The JOSE header looks like this:

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


claims = jwt.GetPayload(idToken)

Dim jsonClaims As Chilkat.JsonObject
Set jsonClaims = Chilkat.NewJsonObject
success = jsonClaims.Load(claims)
jsonClaims.EmitCompact = False
Debug.Print 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..

ver = jsonClaims.StringOf("ver")

iss = jsonClaims.StringOf("iss")

sub = jsonClaims.StringOf("sub")

aud = jsonClaims.StringOf("aud")

exp = jsonClaims.IntOf("exp")

iat = jsonClaims.IntOf("iat")

nbf = jsonClaims.IntOf("nbf")

name = jsonClaims.StringOf("name")

preferred_username = jsonClaims.StringOf("preferred_username")

oid = jsonClaims.StringOf("oid")

tid = jsonClaims.StringOf("tid")

aio = jsonClaims.StringOf("aio")