(PureBasic) 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 PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkHttpResponse.pb"
IncludeFile "CkHttp.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkHttpRequest.pb"

Procedure ChilkatExample()

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

    http.i = CkHttp::ckCreate()
    If http.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    req.i = CkHttpRequest::ckCreate()
    If req.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkHttpRequest::ckAddParam(req,"client_secret","CLIENT_SECRET")
    CkHttpRequest::ckAddParam(req,"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...
    CkHttpRequest::ckAddParam(req,"scope","https://graph.microsoft.com/.default")
    CkHttpRequest::ckAddParam(req,"grant_type","client_credentials")

    ; Use your own tenant ID, for example 4d8fdd66-66d1-43b0-ae5c-e31b4b7de5cd
    url.s = "https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token"
    resp.i = CkHttp::ckPostUrlEncoded(http,url,req)
    If CkHttp::ckLastMethodSuccess(http) <> 1
        Debug CkHttp::ckLastErrorText(http)
        CkHttp::ckDispose(http)
        CkHttpRequest::ckDispose(req)
        ProcedureReturn
    EndIf

    statusCode.i = CkHttpResponse::ckStatusCode(resp)
    Debug "Response status code = " + Str(statusCode)

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckLoad(json,CkHttpResponse::ckBodyStr(resp))
    CkHttpResponse::ckDispose(resp)

    CkJsonObject::setCkEmitCompact(json, 0)
    Debug CkJsonObject::ckEmit(json)

    ; Sample successful output:

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

    If statusCode = 200
        CkJsonObject::ckWriteFile(json,"qa_data/tokens/msGraphClientCredentialsToken.json")
        Debug "Success."
    Else
        Debug "Failed."
    EndIf



    CkHttp::ckDispose(http)
    CkHttpRequest::ckDispose(req)
    CkJsonObject::ckDispose(json)


    ProcedureReturn
EndProcedure