(Visual Basic 6.0) Microsoft Graph -- List Users (Automatic OAuth2 Client Credentials)

Simplify OAuth2 client credentials by using Chilkat to automatically obtain the necessary access token. This example demonstrates the technique with the Microsoft Graph API's "List Users" request.

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.

' Instead of directly sending a POST request to obtain an OAuth2 access token, 
' you can provide Chilkat with the necessary information to automatically fetch 
' the token using the Client Credentials flow. During the first HTTP request, 
' Chilkat will obtain the token if it doesn't have one yet, and then use it for 
' all subsequent requests. When the token is expired or about to expire, Chilkat 
' will automatically obtain a new one, eliminating the need for your application 
' to manage token expiration and renewal manually. This approach also reduces the 
' number of HTTP requests by utilizing valid tokens as long as possible.

Dim json As New ChilkatJsonObject
success = json.UpdateString("client_secret","CLIENT_SECRET")
success = json.UpdateString("client_id","CLIENT_ID")
success = json.UpdateString("token_endpoint","https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token")
success = json.UpdateString("scope","https://graph.microsoft.com/.default")

Dim http As New ChilkatHttp

' Provide the information to let Chilkat automatically obtain the access token.
http.AuthToken = json.Emit()

Dim sbResponse As New ChilkatStringBuilder

Dim success As Long
success = http.QuickGetSb("https://graph.microsoft.com/v1.0/users",sbResponse)
If (success <> 1) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

success = json.LoadSb(sbResponse)
json.EmitCompact = 0

Debug.Print "Status code = " & http.LastStatus
If (http.LastStatus <> 200) Then
    Debug.Print json.Emit()
    Debug.Print "Failed."
End If

Debug.Print json.Emit()

' Sample output
' {
'   "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users",
'   "value": [
'     {
'       "@odata.id": "https://graph.microsoft.com/v2/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/directoryObjects/fca490d8-5918-4201-8079-c5dcbeafcdc9/Microsoft.DirectoryServices.User",
'       "businessPhones": [
'       ],
'       "displayName": "Joe Sample",
'       "givenName": "Joe",
'       "jobTitle": null,
'       "mail": null,
'       "mobilePhone": null,
'       "officeLocation": null,
'       "preferredLanguage": null,
'       "surname": "Sample",
'       "userPrincipalName": "admin_chilkatsoft.com#EXT#@adminchilkatsoft.onmicrosoft.com",
'       "id": "fca490d8-5918-4201-8079-c5dcbeafcdc9"
'     }
'   ]
' }

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

Dim odata_id As String
Dim displayName As String
Dim givenName As String
Dim jobTitle As String
Dim mail As String
Dim mobilePhone As String
Dim officeLocation As String
Dim preferredLanguage As String
Dim surname As String
Dim userPrincipalName As String
Dim id As String
Dim j As Long
Dim count_j As Long

Dim odata_context As String
odata_context = json.StringOf("""@odata.context""")
Dim i As Long
i = 0
Dim count_i As Long
count_i = json.SizeOfArray("value")
Do While i < count_i
    json.I = i
    odata_id = json.StringOf("value[i].""@odata.id""")
    displayName = json.StringOf("value[i].displayName")
    givenName = json.StringOf("value[i].givenName")
    jobTitle = json.StringOf("value[i].jobTitle")
    mail = json.StringOf("value[i].mail")
    mobilePhone = json.StringOf("value[i].mobilePhone")
    officeLocation = json.StringOf("value[i].officeLocation")
    preferredLanguage = json.StringOf("value[i].preferredLanguage")
    surname = json.StringOf("value[i].surname")
    userPrincipalName = json.StringOf("value[i].userPrincipalName")
    id = json.StringOf("value[i].id")
    j = 0
    count_j = json.SizeOfArray("value[i].businessPhones")
    Do While j < count_j
        json.J = j
        j = j + 1
    Loop
    i = i + 1
Loop