(Node.js) ING Open Banking OAuth2 Client Credentials

Demonstrates how to get an access token for the ING Open Banking APIs using client credentials.

For more information, see https://developer.ing.com/openbanking/get-started/openbanking

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var cert = new chilkat.Cert();
    var success = cert.LoadFromFile("qa_data/certs_and_keys/ING/example_client_tls.cer");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var bdPrivKey = new chilkat.BinData();
    success = bdPrivKey.LoadFile("qa_data/certs_and_keys/ING/example_client_tls.key");
    if (success == false) {
        console.log("Failed to load example_client_tls.key");
        return;
    }

    // The OAuth 2.0 client_id for these certificates is e77d776b-90af-4684-bebc-521e5b2614dd. 
    // Please note down this client_id since you will need it in the next steps to call the API.

    var privKey = new chilkat.PrivateKey();
    success = privKey.LoadAnyFormat(bdPrivKey,"");
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    // Associate the private key with the certificate.
    success = cert.SetPrivateKey(privKey);
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var http = new chilkat.Http();

    success = http.SetSslClientCert(cert);
    if (success == false) {
        console.log(http.LastErrorText);
        return;
    }

    // Calculate the Digest and add the "Digest" header.  Do the equivalent of this:
    // payload="grant_type=client_credentials"
    // payloadDigest=`echo -n "$payload" | openssl dgst -binary -sha256 | openssl base64`
    // digest=SHA-256=$payloadDigest
    var crypt = new chilkat.Crypt2();
    crypt.HashAlgorithm = "SHA256";
    crypt.EncodingMode = "base64";
    var payload = "grant_type=client_credentials";
    var payloadDigest = crypt.HashStringENC(payload);

    // Calculate the current date/time and add the Date header.  
    // reqDate=$(LC_TIME=en_US.UTF-8 date -u "+%a, %d %b %Y %H:%M:%S GMT")  
    var dt = new chilkat.CkDateTime();
    dt.SetFromCurrentSystemTime();
    // The desire date/time format is the "RFC822" format.
    http.SetRequestHeader("Date",dt.GetAsRfc822(false));

    // Calculate signature for signing your request
    // Duplicate the following code:

    // 	httpMethod="post"
    // 	reqPath="/oauth2/token"
    // 	signingString="(request-target): $httpMethod $reqPath
    // 	date: $reqDate
    // 	digest: $digest"
    // 	signature=`printf "$signingString" | openssl dgst -sha256 -sign "${certPath}example_client_signing.key" -passin "pass:changeit" | openssl base64 -A`

    var httpMethod = "POST";
    var reqPath = "/oauth2/token";

    var sbStringToSign = new chilkat.StringBuilder();
    sbStringToSign.Append("(request-target): ");
    sbStringToSign.Append(httpMethod);
    sbStringToSign.ToLowercase();
    sbStringToSign.Append(" ");
    sbStringToSign.AppendLine(reqPath,false);

    sbStringToSign.Append("date: ");
    sbStringToSign.AppendLine(dt.GetAsRfc822(false),false);

    sbStringToSign.Append("digest: SHA-256=");
    sbStringToSign.Append(payloadDigest);

    var signingPrivKey = new chilkat.PrivateKey();
    success = signingPrivKey.LoadPemFile("qa_data/certs_and_keys/ING/example_client_signing.key");
    if (success == false) {
        console.log(signingPrivKey.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();
    success = rsa.ImportPrivateKeyObj(signingPrivKey);
    if (success == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    rsa.EncodingMode = "base64";
    var b64Signature = rsa.SignStringENC(sbStringToSign.GetAsString(),"SHA256");

    var sbAuthHdrVal = new chilkat.StringBuilder();
    sbAuthHdrVal.Append("Signature keyId=\"e77d776b-90af-4684-bebc-521e5b2614dd\",");
    sbAuthHdrVal.Append("algorithm=\"rsa-sha256\",");
    sbAuthHdrVal.Append("headers=\"(request-target) date digest\",");
    sbAuthHdrVal.Append("signature=\"");
    sbAuthHdrVal.Append(b64Signature);
    sbAuthHdrVal.Append("\"");

    var sbDigestHdrVal = new chilkat.StringBuilder();
    sbDigestHdrVal.Append("SHA-256=");
    sbDigestHdrVal.Append(payloadDigest);

    // Do the following CURL statement:

    // 	curl -i -X POST "${httpHost}${reqPath}" \
    // 	-H 'Accept: application/json' \
    // 	-H 'Content-Type: application/x-www-form-urlencoded' \
    // 	-H "Digest: ${digest}" \
    // 	-H "Date: ${reqDate}" \
    // 	-H "authorization: Signature keyId=\"$keyId\",algorithm=\"rsa-sha256\",headers=\"(request-target) date digest\",signature=\"$signature\"" \
    // 	-d "${payload}" \
    // 	--cert "${certPath}tlsCert.crt" \
    // 	--key "${certPath}tlsCert.key"

    var req = new chilkat.HttpRequest();
    req.AddParam("grant_type","client_credentials");
    req.AddHeader("Accept","application/json");
    req.AddHeader("Date",dt.GetAsRfc822(false));
    req.AddHeader("Digest",sbDigestHdrVal.GetAsString());
    req.AddHeader("Authorization",sbAuthHdrVal.GetAsString());
    // resp: HttpResponse
    var resp = http.PostUrlEncoded("https://api.sandbox.ing.com/oauth2/token",req);
    if (http.LastMethodSuccess == false) {
        console.log(http.LastErrorText);
        return;
    }

    // If successful, the status code = 200
    console.log("Response Status Code: " + resp.StatusCode);
    console.log(resp.BodyStr);

    var json = new chilkat.JsonObject();
    json.Load(resp.BodyStr);

    json.EmitCompact = false;
    console.log(json.Emit());

    // A successful response contains an access token such as:
    // {
    //   "access_token": "eyJhbGc ... bxI_SoPOBH9xmoM",
    //   "expires_in": 905,
    //   "scope": "payment-requests:view payment-requests:create payment-requests:close greetings:view virtual-ledger-accounts:fund-reservation:create virtual-ledger-accounts:fund-reservation:delete virtual-ledger-accounts:balance:view",
    //   "token_type": "Bearer",
    //   "keys": [
    //     {
    //       "kty": "RSA",
    //       "n": "3l3rdz4...04VPkdV",
    //       "e": "AQAB",
    //       "use": "sig",
    //       "alg": "RS256",
    //       "x5t": "3c396700fc8cd709cf9cb5452a22bcde76985851"
    //     }
    //   ],
    //   "client_id": "e77d776b-90af-4684-bebc-521e5b2614dd"
    // }

    // Use this online tool to generate parsing code from sample JSON: 
    // Generate Parsing Code from JSON

    var kty;
    var n;
    var e;
    var use;
    var alg;
    var x5t;

    var access_token = json.StringOf("access_token");
    var expires_in = json.IntOf("expires_in");
    var scope = json.StringOf("scope");
    var token_type = json.StringOf("token_type");
    var client_id = json.StringOf("client_id");
    var i = 0;
    var count_i = json.SizeOfArray("keys");
    while (i < count_i) {
        json.I = i;
        kty = json.StringOf("keys[i].kty");
        n = json.StringOf("keys[i].n");
        e = json.StringOf("keys[i].e");
        use = json.StringOf("keys[i].use");
        alg = json.StringOf("keys[i].alg");
        x5t = json.StringOf("keys[i].x5t");
        i = i+1;
    }

    // This example will save the JSON containing the access key to a file so that
    // a subsequent example can load it and then use the access key for a request, such as to create a payment request.
    json.WriteFile("qa_data/tokens/ing_access_token.json");

}

chilkatExample();