(Visual FoxPro) 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

LOCAL loHttp
LOCAL loReq
LOCAL lcUrl
LOCAL loResp
LOCAL lnStatusCode
LOCAL loJson

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Http')
loHttp = CreateObject('Chilkat.Http')

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.HttpRequest')
loReq = CreateObject('Chilkat.HttpRequest')
loReq.AddParam("client_secret","CLIENT_SECRET")
loReq.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...
loReq.AddParam("scope","https://graph.microsoft.com/.default")
loReq.AddParam("grant_type","client_credentials")

* Use your own tenant ID, for example 4d8fdd66-66d1-43b0-ae5c-e31b4b7de5cd
lcUrl = "https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token"
loResp = loHttp.PostUrlEncoded(lcUrl,loReq)
IF (loHttp.LastMethodSuccess <> 1) THEN
    ? loHttp.LastErrorText
    RELEASE loHttp
    RELEASE loReq
    CANCEL
ENDIF

lnStatusCode = loResp.StatusCode
? "Response status code = " + STR(lnStatusCode)

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.Load(loResp.BodyStr)
RELEASE loResp

loJson.EmitCompact = 0
? loJson.Emit()

* Sample successful output:

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

IF (lnStatusCode = 200) THEN
    loJson.WriteFile("qa_data/tokens/msGraphClientCredentialsToken.json")
    ? "Success."
ELSE
    ? "Failed."
ENDIF

RELEASE loHttp
RELEASE loReq
RELEASE loJson