(Excel) Get an Azure AD Access Token

Demonstrates how to obtain an Azure AD access token for authentication using a client ID, client secret, and tenant ID.

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

Dim socket As Chilkat.Socket
Set socket = Chilkat.NewSocket

' Make a TLS connection to login.microsoftonline.com, waiting at most 5000 milliseconds.

success = socket.Connect("login.microsoftonline.com",443,True,5000)
If (success <> True) Then
    Debug.Print socket.LastErrorText
    Exit Sub
End If

' Create an Azure AD auth object, and provide the required information for authorization.
Dim azureAD As Chilkat.AuthAzureAD
Set azureAD = Chilkat.NewAuthAzureAD
azureAD.ClientId = "AZURE_AD_CLIENT_ID"
azureAD.ClientSecret = "AZURE_AD_CLIENT_SECRET"
azureAD.TenantId = "AZURE_TENANT_ID"

azureAD.Resource = "https://outlook.office365.com/"

' Retrieve the access token using the TLS connection to login.microsoftonline.com
success = azureAD.ObtainAccessToken(socket)
If (success <> True) Then
    Debug.Print socket.LastErrorText
    Exit Sub
End If

' Show the access token, and then save it to a JSON file
' for future use (such as with a REST method call).
Debug.Print "Azure AD Access Token = "; azureAD.AccessToken

Dim json As Chilkat.JsonObject
Set json = Chilkat.NewJsonObject
Dim success As Boolean
success = json.AppendString("accessToken",azureAD.AccessToken)

' Save our access token to a file.  It will be used in subsequent REST API calls.
Dim fac As Chilkat.FileAccess
Set fac = Chilkat.NewFileAccess
success = fac.WriteEntireTextFile("qa_data/tokens/azureAD_office365.json",json.Emit(),"utf-8",False)

' Let's get the id information out of the access token.
' Our JSON looks like this:
' {"accessToken":"eyJ0eXAiO---TdjT3RjIn0.eyJhdWQiOiJo---jEuMCJ9.CIx0sUT8s---KvzKKUw"}

' I used "---" instead of "..." to indicate a large quantity of omitted chars.
' The accessToken is a long string composed of 3 base64 strings concatenated with "." chars.
' The 1st part is the JOSE header.  If you decode from base64, you'll get the JSON JOSE header.
' The 2nd part is the id token.  When decoded this is the JSON that contains information about the authenticated application.
' The 3rd part is binary and does not decode to JSON.

' Let's get the information from the 2nd part (the id token)
Dim sa As Chilkat.StringArray
Set sa = Chilkat.NewStringArray
sa.SplitAndAppend json.StringOf("accessToken"),"."

Dim sbIdToken As Chilkat.StringBuilder
Set sbIdToken = Chilkat.NewStringBuilder
' The 2nd string is at index 1.
success = sbIdToken.Append(sa.GetString(1))
success = sbIdToken.Decode("base64","utf-8")

Dim jsonIdToken As Chilkat.JsonObject
Set jsonIdToken = Chilkat.NewJsonObject
success = jsonIdToken.LoadSb(sbIdToken)
jsonIdToken.EmitCompact = False
Debug.Print jsonIdToken.Emit()

' We have something like this:
' {
'   "aud": "https://outlook.office365.com/",
'   "iss": "https://sts.windows.net/6e8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/",
'   "iat": 1586350465,
'   "nbf": 1586350465,
'   "exp": 1586354365,
'   "aio": "42dgYNjyOtX8ZZB7JLfMFJGeKUmvAA==",
'   "app_displayname": "ChilkatTest",
'   "appid": "f125d695-c50e-456e-a578-a486f06d1213",
'   "appidacr": "1",
'   "idp": "https://sts.windows.net/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/",
'   "oid": "7545a2fd-3f0d-48a4-9c58-a1a5700a24b1",
'   "sid": "ab981252-9378-4d0c-964b-eb2e1451138f",
'   "sub": "7546a2fc-3f0d-48a4-9c58-a1a5700a24b1",
'   "tid": "6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd",
'   "uti": "huIJBAa1tvGpczwV5S1BAA",
'   "ver": "1.0"
' }

' Get the desired information from the JSON:

aud = jsonIdToken.StringOf("aud")

iss = jsonIdToken.StringOf("iss")

iat = jsonIdToken.IntOf("iat")

nbf = jsonIdToken.IntOf("nbf")

exp = jsonIdToken.IntOf("exp")

aio = jsonIdToken.StringOf("aio")

app_displayname = jsonIdToken.StringOf("app_displayname")

appid = jsonIdToken.StringOf("appid")

appidacr = jsonIdToken.StringOf("appidacr")

idp = jsonIdToken.StringOf("idp")

oid = jsonIdToken.StringOf("oid")

sid = jsonIdToken.StringOf("sid")

sub = jsonIdToken.StringOf("sub")

tid = jsonIdToken.StringOf("tid")

uti = jsonIdToken.StringOf("uti")

ver = jsonIdToken.StringOf("ver")