(DataFlex) Get Access Token using a Pre-Created JSON Web Token

Demonstrates how to get an access token using a pre-created JSON Web Token (JWT).

For more information, see https://developer.abnamro.com/get-started#headingFive

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Variant vPrivkey
    Handle hoPrivkey
    Boolean iSuccess
    Handle hoJwt
    Handle hoJsonHeader
    Handle hoJsonPayload
    Integer iCurDateTime
    String sJwtStr
    Handle hoHttp
    Variant vReq
    Handle hoReq
    Variant vResp
    Handle hoResp
    Handle hoJson
    String sTemp1
    String sTemp2
    Integer iTemp1
    Boolean bTemp1

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

    // We're going to duplicate this CURL statement:
    // curl -X POST https://api-sandbox.abnamro.com/v1/oauth/token \
    // -H "Content-Type: application/x-www-form-urlencoded" \
    // -H "API-Key: xxxxxx" \
    // -d 'client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer&grant_type=client_credentials&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ4eHh4eHgiLCJleHAiOiIxNDk5OTQ3NjY4IiwiaXNzIjoibWUiLCJhdWQiOiJodHRwczovL2F1dGgtc2FuZGJveC5hYm5hbXJvLmNvbS9vYXV0aC90b2tlbiJ9.jGwHKG_YjgKpR8NPpaLu6nJ97obeP2vcxg6fOWBKdJ0&scope=tikkie'

    // Load our pre-creaed private key PEM file.
    // Note: Please share your public key along with your app name and developer email id at api.support@nl.abnamro.com. 
    // Token generation will not work unless public key is associated with your app.
    Get Create (RefClass(cComChilkatPrivateKey)) To hoPrivkey
    If (Not(IsComObjectCreated(hoPrivkey))) Begin
        Send CreateComObject of hoPrivkey
    End

    Get ComLoadPemFile Of hoPrivkey "qa_data/pem/abnAmroPrivateKey.pem" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPrivkey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Create the JWT.
    Get Create (RefClass(cComChilkatJwt)) To hoJwt
    If (Not(IsComObjectCreated(hoJwt))) Begin
        Send CreateComObject of hoJwt
    End

    // Create the header:
    // {
    //     "typ": "JWT",
    //     "alg": "RS256"
    // }
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonHeader
    If (Not(IsComObjectCreated(hoJsonHeader))) Begin
        Send CreateComObject of hoJsonHeader
    End
    Get ComUpdateString Of hoJsonHeader "typ" "JWT" To iSuccess
    Get ComUpdateString Of hoJsonHeader "alg" "RS256" To iSuccess

    // Create the payload:
    // {
    //     "nbf": 1499947668,
    //     "exp": 1499948668,
    //     "iss": "me",
    //     "sub": "anApiKey",
    //     "aud": "https://auth-sandbox.abnamro.com/oauth/token"
    // }
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonPayload
    If (Not(IsComObjectCreated(hoJsonPayload))) Begin
        Send CreateComObject of hoJsonPayload
    End

    Get ComGenNumericDate Of hoJwt 0 To iCurDateTime

    // Set the "not process before" timestamp to now.
    Get ComAddIntAt Of hoJsonPayload -1 "nbf" iCurDateTime To iSuccess

    // Set the timestamp defining an expiration time (end time) for the token
    // to be now + 1 hour (3600 seconds)
    Get ComAddIntAt Of hoJsonPayload -1 "exp" (iCurDateTime + 3600) To iSuccess

    Get ComUpdateString Of hoJsonPayload "iss" "me" To iSuccess
    Get ComUpdateString Of hoJsonPayload "sub" "anApiKey" To iSuccess
    Get ComUpdateString Of hoJsonPayload "aud" "https://auth-sandbox.abnamro.com/oauth/token" To iSuccess

    // Produce the smallest possible JWT:
    Set ComAutoCompact Of hoJwt To True

    Get ComEmit Of hoJsonHeader To sTemp1
    Get ComEmit Of hoJsonPayload To sTemp2
    Get pvComObject of hoPrivkey to vPrivkey
    Get ComCreateJwtPk Of hoJwt sTemp1 sTemp2 vPrivkey To sJwtStr
    Get ComLastMethodSuccess Of hoJwt To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoJwt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    Get Create (RefClass(cComChilkatHttpRequest)) To hoReq
    If (Not(IsComObjectCreated(hoReq))) Begin
        Send CreateComObject of hoReq
    End
    Send ComAddParam To hoReq "client_assertion_type" "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"
    Send ComAddParam To hoReq "grant_type" "client_credentials"
    Send ComAddParam To hoReq "client_assertion" sJwtStr
    Send ComAddParam To hoReq "scope" "tikkie"

    Get pvComObject of hoReq to vReq
    Get ComPostUrlEncoded Of hoHttp "https://api-sandbox.abnamro.com/v1/oauth/token" vReq To vResp
    If (IsComObject(vResp)) Begin
        Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
        Set pvComObject Of hoResp To vResp
    End
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComStatusCode Of hoResp To iTemp1
    If (iTemp1 <> 200) Begin
        Get ComBodyStr Of hoResp To sTemp1
        Showln sTemp1
        Send Destroy of hoResp
        Procedure_Return
    End

    // Get the JSON result:
    // {
    //     "access_token": "{your access token}",
    //     "expires_in": "{duration of validity in seconds}",
    //     "scope": "{scope(s) for which the access token is valid}",
    //     "token_type": "{it is always Bearer}"
    // }
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComBodyStr Of hoResp To sTemp1
    Get ComLoad Of hoJson sTemp1 To iSuccess
    Get ComStringOf Of hoJson "access_token" To sTemp1
    Showln "access_token: " sTemp1
    Get ComStringOf Of hoJson "token_type" To sTemp1
    Showln "token_type: " sTemp1
    Get ComStringOf Of hoJson "expires_in" To sTemp1
    Showln "expires_in: " sTemp1
    Get ComStringOf Of hoJson "scope" To sTemp1
    Showln "scope: " sTemp1

    Send Destroy of hoResp


End_Procedure