(DataFlex) Verify Okta Access Token Locally

This example demonstrates how to validate an Okta access token using Chilkat's JWT class.

For more information, see https://developer.okta.com/docs/guides/validate-access-tokens/overview/#what-to-check-when-validating-an-access-token

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

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Handle hoJsonToken
    Boolean iSuccess
    Handle hoJsonWebKeys
    Handle hoJwt
    String sAccessToken
    String sJoseHeader
    Handle hoJson
    String sKid
    Variant vSbKid
    Handle hoSbKid
    String e
    String n
    Integer i
    Integer iCount_i
    Boolean iBFound
    Integer iIMatch
    Variant vPubkey
    Handle hoPubkey
    Variant vJsonWebKey
    Handle hoJsonWebKey
    Boolean iBVerified
    String sTemp1
    Boolean bTemp1

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

    // This example begins with two JSON files:
    // 
    // 1. The access token obtained from Okta as shown in one fo these examples:  
    //    Get Okta Token using Resource Owner Password Flow
    // 
    // 2. The Okta web keys obtained by this example:  Get Okta Web Keys
    // 
    // 

    // Load the access token to be verified.
    // It contains JSON that looks like this:
    // {
    //   "access_token": "eyJraWQiOiJhb ... O_eVu-kBp6g",
    //   "token_type": "Bearer",
    //   "expires_in": 3600,
    //   "scope": "openid",
    //   "id_token": "eyJraWQi ... FrL9WOuwbQtUg"
    // }
    // This example verifies the access_token.  (The id_token is verified in this example:  Verify Okta ID Token

    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonToken
    If (Not(IsComObjectCreated(hoJsonToken))) Begin
        Send CreateComObject of hoJsonToken
    End
    Get ComLoadFile Of hoJsonToken "qa_data/tokens/okta_access_token.json" To iSuccess

    // Load the public keys (Okta web keys), one of which is needed to validate.
    // The web keys JSON looks like this:
    // {
    //   "keys": [
    //     {
    //       "kty": "RSA",
    //       "alg": "RS256",
    //       "kid": "anSaRDPfWGOSCVNZEIZB9quCbNsdsvl5uWGBzxbudWQ",
    //       "use": "sig",
    //       "e": "AQAB",
    //       "n": "jT8uAgd5w ... euLB1HaVw"
    //     },
    //     {
    // 	...
    //     }
    //   ]
    // }

    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonWebKeys
    If (Not(IsComObjectCreated(hoJsonWebKeys))) Begin
        Send CreateComObject of hoJsonWebKeys
    End
    Get ComLoadFile Of hoJsonWebKeys "qa_data/tokens/okta_web_keys.json" To iSuccess

    // ------------------------
    // Step 1: Get the JOSE header from the JWT.  The JOSE header contains JSON.  One of the JSON members will be the key ID "kid" which identifies the web key to be used for validation.
    // 
    Get Create (RefClass(cComChilkatJwt)) To hoJwt
    If (Not(IsComObjectCreated(hoJwt))) Begin
        Send CreateComObject of hoJwt
    End
    Get ComStringOf Of hoJsonToken "access_token" To sAccessToken
    Get ComGetHeader Of hoJwt sAccessToken To sJoseHeader

    Showln sJoseHeader
    // The joseHeader contains this:   {"kid":"anSaRDPfWGOSCVNZEIZB9quCbNsdsvl5uWGBzxbudWQ","alg":"RS256"}

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComLoad Of hoJson sJoseHeader To iSuccess
    Get ComStringOf Of hoJson "kid" To sKid
    Showln "kid to find: " sKid

    // ------------------------
    // Step 2: Find the key with the same "kid" in the Okta web keys.

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbKid
    If (Not(IsComObjectCreated(hoSbKid))) Begin
        Send CreateComObject of hoSbKid
    End
    Move "" To e
    Move "" To n

    Move 0 To i
    Get ComSizeOfArray Of hoJsonWebKeys "keys" To iCount_i
    Move False To iBFound
    Move 0 To iIMatch
    While ((iBFound = False) And (i < iCount_i))
        Set ComI Of hoJsonWebKeys To i
        Send ComClear To hoSbKid
        Get pvComObject of hoSbKid to vSbKid
        Get ComStringOfSb Of hoJsonWebKeys "keys[i].kid" vSbKid To iSuccess
        Get ComGetAsString Of hoSbKid To sTemp1
        Showln "checking kid: " sTemp1

        Get ComContentsEqual Of hoSbKid sKid True To bTemp1
        If (bTemp1 = True) Begin
            Get ComStringOf Of hoJsonWebKeys "keys[i].e" To e
            Get ComStringOf Of hoJsonWebKeys "keys[i].n" To n
            // Exit the loop. 
            Showln "Found matching kid."
            Move i To iIMatch
            Move True To iBFound
        End

        Move i + 1 To i
    Loop

    If (iBFound = False) Begin
        Showln "No matching key ID found."
        Procedure_Return
    End

    Showln "Matching key:"
    Showln "  exponent = " e
    Showln "  modulus = " n

    // ------------------------
    // Step 3: Load the RSA modulus and exponent into a Chilkat public key object.
    Get Create (RefClass(cComChilkatPublicKey)) To hoPubkey
    If (Not(IsComObjectCreated(hoPubkey))) Begin
        Send CreateComObject of hoPubkey
    End

    // Get the matching JSON key from the array of keys.
    Set ComI Of hoJsonWebKeys To iIMatch
    Get ComObjectOf Of hoJsonWebKeys "keys[i]" To vJsonWebKey
    If (IsComObject(vJsonWebKey)) Begin
        Get Create (RefClass(cComChilkatJsonObject)) To hoJsonWebKey
        Set pvComObject Of hoJsonWebKey To vJsonWebKey
    End
    Get ComEmit Of hoJsonWebKey To sTemp1
    Get ComLoadFromString Of hoPubkey sTemp1 To iSuccess
    If (iSuccess = False) Begin
        Showln "Failed to load JSON web key."
        Get ComEmit Of hoJsonWebKey To sTemp1
        Showln sTemp1
        Get ComLastErrorText Of hoPubkey To sTemp1
        Showln sTemp1
        Send Destroy of hoJsonWebKey
        Procedure_Return
    End

    Send Destroy of hoJsonWebKey
    Showln "successfully loaded web key."

    // OK.. we have the desired JSON web key loaded into our public key object.
    // Now we can verify the access token.

    // ------------------------
    // Step 4: Verify the access token.
    Get pvComObject of hoPubkey to vPubkey
    Get ComVerifyJwtPk Of hoJwt sAccessToken vPubkey To iBVerified
    If (iBVerified = True) Begin
        Showln "The access token is valid."
    End
    Else Begin
        Showln "The access token is NOT valid."
    End



End_Procedure