(Node.js) SII Chile - FRMA Signature Computation and Add to XML

Compute the FRMA signature of a <DA> element enclosed inside a <CAF> element of the XML to be signed.

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

    // Also see:  Compute the FRMT Signature and Add to XML

    var xml = new chilkat.Xml();

    // Load the unsigned XML that contains the following:

    // <DTE version="1.0">
    //   <Documento ID="F60T33">
    //         <TED version="1.0">
    //             <DD>
    // 		...
    //                 <CAF version="1.0">
    //                     <DA>
    // 			...
    //                     </DA>
    // 			... The FRMA will be added here ...
    //                 </CAF>
    //                 ...
    //             </DD>
    //             ... The FRMT will be added here in another example ...
    //         </TED>
    //   </Documento>
    // </DTE>

    var success = xml.LoadXmlFile("qa_data/xml_dsig/sii_cl/test_0.xml");
    if (success == false) {
        console.log("Failed to load initial XML file.");
        return;
    }

    // Get a reference to the "DA" element
    // daXml: Xml
    var daXml = xml.FindChild("Documento|TED|DD|CAF|DA");
    if (xml.LastMethodSuccess == false) {
        console.log("Failed to find DA element");
        return;
    }

    //  We need to get the "flattened" DA XML where:
    //    - No whitespace between elements.
    //    - The 5 pre-defined entities are converted.
    //    - The text is encoded in the ISO-8859-1 character set (Latin-1), 
    var sbFlattened = new chilkat.StringBuilder();
    daXml.EmitCompact = true;
    daXml.EmitXmlDecl = false;
    daXml.GetXmlSb(sbFlattened);

    // Compute the SHA-1 message digest of the iso-8859-1 byte representation, 
    // and sign it with our RSA private key, getting the result in base64 format.

    var privKey = new chilkat.PrivateKey();
    success = privKey.LoadAnyFormatFile("qa_data/rsa/rsaPrivKey_pkcs8.pem","");
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    var rsa = new chilkat.Rsa();
    rsa.ImportPrivateKeyObj(privKey);

    rsa.EncodingMode = "base64";
    rsa.Charset = "iso-8859-1";
    var sig = rsa.SignStringENC(sbFlattened.GetAsString(),"sha1");

    // Add the FRMA signature element to the XML.
    xml.UpdateChildContent("Documento|TED|DD|CAF|FRMA",sig);
    xml.UpdateAttrAt("Documento|TED|DD|CAF|FRMA",true,"algoritmo","SHA1withRSA");

    // See what we have:
    xml.EmitCompact = false;
    xml.EmitXmlDecl = true;
    console.log(xml.GetXml());

    xml.SaveXml("qa_data/xml_dsig/sii_cl/test_1.xml");

}

chilkatExample();