(PureBasic) Azure AD Service-to-service access token request

Send an Azure AD service-to-service token request to get an access token using a shared secret.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v1-oauth2-client-creds-grant-flow#service-to-service-access-token-request

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

    ; To see the exact HTTP request sent and the response, set the SessionLogFilename property:
    CkHttp::setCkSessionLogFilename(http, "qa_output/chilkatHttpLog.txt")

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

    ; Set the following request params:
    ; grant_type 	required 	Specifies the requested grant type. In a Client Credentials Grant flow, the value must be client_credentials.
    ; 
    ; client_id 	required 	Specifies the Azure AD client id of the calling web service. 
    ;     To find the calling application's client ID, in the Azure portal, click Azure Active Directory, click App registrations, click the application. 
    ;     The client_id is the Application ID
    ; 
    ; client_secret 	required 	Enter a key registered for the calling web service or daemon application in Azure AD. 
    ;     To create a key, in the Azure portal, click Azure Active Directory, click App registrations, click the application, click Settings, click Keys, and add a Key.
    ;     URL-encode this secret when providing it.
    ; 
    ; resource 	required 	Enter the App ID URI of the receiving web service. To find the App ID URI, in the Azure portal, click Azure Active Directory, 
    ;     click App registrations, click the service application, and then click Settings and Properties.

    CkHttpRequest::ckAddParam(req,"grant_type","client_credentials")
    CkHttpRequest::ckAddParam(req,"client_id","MY_CLIENT_ID")
    CkHttpRequest::ckAddParam(req,"client_secret","MY_CLIENT_SECRET")
    CkHttpRequest::ckAddParam(req,"resource","https://service.contoso.com/")

    ; The URL passed to PostUrlEncoded has this form:   https://login.microsoftonline.com/<tenant_id>/oauth2/token
    resp.i = CkHttp::ckPostUrlEncoded(http,"https://login.microsoftonline.com/<tenant_id>/oauth2/token",req)
    If CkHttp::ckLastMethodSuccess(http) = 0
        Debug CkHttp::ckLastErrorText(http)
        CkHttp::ckDispose(http)
        CkHttpRequest::ckDispose(req)
        ProcedureReturn
    EndIf

    respStatusCode.i = CkHttpResponse::ckStatusCode(resp)
    Debug "Response Status Code = " + Str(respStatusCode)

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

    CkJsonObject::setCkEmitCompact(json, 0)
    CkJsonObject::ckLoad(json,CkHttpResponse::ckBodyStr(resp))
    Debug "Response JSON:"
    Debug CkJsonObject::ckEmit(json)

    If respStatusCode >= 400
        Debug "Response Header:"
        Debug CkHttpResponse::ckHeader(resp)
        Debug "Failed."
        CkHttpResponse::ckDispose(resp)

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

    ; Sample response:

    ; {
    ;   "token_type": "Bearer",
    ;   "expires_in": "3599",
    ;   "ext_expires_in": "3599",
    ;   "expires_on": "1570059833",
    ;   "not_before": "1570055933",
    ;   "resource": "https://adminchilkatsoft.onmicrosoft.com/eb1b8ced-76b7-4845-aec5-d3e91776e345",
    ;   "access_token": "eyJ0eXAiO ... pmgw"
    ; }

    ; To get the items from the JSON....
    token_type.s = CkJsonObject::ckStringOf(json,"token_type")
    expires_in.s = CkJsonObject::ckStringOf(json,"expires_in")
    ext_expires_in.s = CkJsonObject::ckStringOf(json,"ext_expires_in")
    expires_on.s = CkJsonObject::ckStringOf(json,"expires_on")
    not_before.s = CkJsonObject::ckStringOf(json,"not_before")
    resource.s = CkJsonObject::ckStringOf(json,"resource")
    access_token.s = CkJsonObject::ckStringOf(json,"access_token")

    CkHttpResponse::ckDispose(resp)



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


    ProcedureReturn
EndProcedure