How to use getdns - 10 common examples

/* eslint-disable no-console */
    console.log("resolver = " + req.query.resolver);
    console.log("query = " + req.query.query);
    console.log("hostname = " + req.query.hostname);
    /* eslint-enable no-console */

    const porttls = 853;
    const upstreamresolvers = [];
    upstreamresolvers.push(req.query.resolver);
    upstreamresolvers.push(porttls);
    upstreamresolvers.push(req.query.hostname);
    const up1 = [];
    up1.push(upstreamresolvers);

    // Create the contexts we need to test with the above options.
    const context = getdns.createContext(options);
    context.upstream_recursive_servers = up1;
    context.timeout = 10000;
    context.tls_authentication = getdns.AUTHENTICATION_HOSTNAME;
    //g context.upstream_recursive_servers = resolver;
    context.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const context1 = getdns.createContext(options);
    context1.upstream_recursive_servers = up1;
    context1.timeout = 10000;
    context1.tls_authentication = getdns.AUTHENTICATION_NONE;
    context1.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const porttcp = 53;
    const upstreamresolvertcp = [];
    upstreamresolvertcp.push(resolver);
    upstreamresolvertcp.push(porttcp);

res1 += "<ul>";
    res1 += "<li>Target Resolver: " + resolver + "</li>";
    res1 += "<li>Recursive's Hostname in Certificate (SubjectName): " + hostname + "</li>";
    res1 += "</ul>";

    res1 += "<h2>Checking for</h2>";
    res1 += "<ol>";
    res1 += "<li>Successful TCP connection</li>";
    res1 += "<li>Successful TLS connection</li>";
    res1 += "<li>Successful TLS Authentication (Hostname match to server certificate)</li>";
    res1 += "<li>Opportunistic TLS with fallback to TCP available</li>";
    res1 += "</ol>";

    res1 += "<h2>Result</h2>";

    context.general(query, getdns.RRTYPE_A, (err0, result0) =&gt; {
        if (err0) {
            // NOTE: TLS auth error.
            context.destroy();
            context1.general(query, getdns.RRTYPE_A, (err1, result1) =&gt; {
                if (err1) {
                    // NOTE: Try TLS no auth.
                    context1.destroy();
                    context2.general(query, getdns.RRTYPE_A, (err2, result2) =&gt; {
                        if (err2) {
                            // NOTE: TCP only failed.
                            /* eslint-disable no-console */
                            console.error("Error2 = " + JSON.stringify(err2));
                            /* eslint-enable no-console */

                            res1 += "<p>❌ No TCP, no TLS!</p>";
                        } else if (result2.status === 900) {

context.general(query, getdns.RRTYPE_A, (err0, result0) => {
        if (err0) {
            // NOTE: TLS auth error.
            context.destroy();
            context1.general(query, getdns.RRTYPE_A, (err1, result1) => {
                if (err1) {
                    // NOTE: Try TLS no auth.
                    context1.destroy();
                    context2.general(query, getdns.RRTYPE_A, (err2, result2) => {
                        if (err2) {
                            // NOTE: TCP only failed.
                            /* eslint-disable no-console */
                            console.error("Error2 = " + JSON.stringify(err2));
                            /* eslint-enable no-console */

                            res1 += "<p>❌ No TCP, no TLS!</p>";
                        } else if (result2.status === 900) {
                            // NOTE: TCP worked.

                            /* eslint-disable no-console */
                            console.log("In callback TCP fallback worked " + JSON.stringify(result2.replies_tree));

console.log("hostname = " + req.query.hostname);
    /* eslint-enable no-console */

    const porttls = 853;
    const upstreamresolvers = [];
    upstreamresolvers.push(req.query.resolver);
    upstreamresolvers.push(porttls);
    upstreamresolvers.push(req.query.hostname);
    const up1 = [];
    up1.push(upstreamresolvers);

    // Create the contexts we need to test with the above options.
    const context = getdns.createContext(options);
    context.upstream_recursive_servers = up1;
    context.timeout = 10000;
    context.tls_authentication = getdns.AUTHENTICATION_HOSTNAME;
    //g context.upstream_recursive_servers = resolver;
    context.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const context1 = getdns.createContext(options);
    context1.upstream_recursive_servers = up1;
    context1.timeout = 10000;
    context1.tls_authentication = getdns.AUTHENTICATION_NONE;
    context1.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const porttcp = 53;
    const upstreamresolvertcp = [];
    upstreamresolvertcp.push(resolver);
    upstreamresolvertcp.push(porttcp);
    const up2 = [];
    up2.push(upstreamresolvertcp);
    const context2 = getdns.createContext(options);

const serviceCallback = displayLookupResults.bind(null, "service");
const hostnameCallback = displayLookupResults.bind(null, "hostname");

const options = {
    // Request timeout time in milliseconds.
    timeout: 5000,
    "upstreams": [
        "8.8.8.8",
    ],
    // Always return dnssec status.
    return_dnssec_status: true,
};

// Create the context with the above options.
// When done with a context, it must be explicitly destroyed, for example in a callback.
const context = getdns.createContext(options);

// Getdns general.
// Third argument may be a dictionary for extensions.
// Last argument must be a callback.
// Returns a transaction id, which may be used to cancel the request.
/* eslint-disable no-unused-vars */
const transactionId = context.general("labs.verisigninc.com", getdns.RRTYPE_A, generalCallback);
/* eslint-enable no-unused-vars */

// Cancel a request.
//context.cancel(transactionId);

// Other getdns context methods.
// NOTE: don't destroy context in callback so it can be reused.
// Extensions are passed as dictionaries where the value for on/off are normal booleans.
context.address("nlnetlabs.nl", { dnssec_return_only_secure: true }, addressCallback);

const TLSA_NAME = "77fa5113ab6a532ce2e6901f3bd3351c0db5845e0b1b5fb09907808d._smimecert.getdnsapi.org";
const TLSA_TYPE = getdns.RRTYPE_TLSA;

// Message.
const MESSAGE = "Hello, World";

// Context options.
const options = {
    return_dnssec_status: true,
  // Request timeout time in millis.
    timeout: 5000,
};

// Create the context with the above options.
const context = getdns.createContext(options);

// Response util - get a secure response of a particular type.
const getFirstSecureResponse = (result, type) => {
    const repliesTree = result.replies_tree;
    // Validate that there is a reply with an answer.
    if (!repliesTree || !repliesTree.length
        || !repliesTree[0].answer
        || !repliesTree[0].answer.length) {
        return "empty answer list for type " + type;
    }
    const reply = repliesTree[0];

    // Ensure the reply is secure.
    if (reply.dnssec_status !== getdns.DNSSEC_SECURE) {
        return "insecure reply for type " + type;
    }

const upstreamresolvers = [];
    upstreamresolvers.push(req.query.resolver);
    upstreamresolvers.push(porttls);
    upstreamresolvers.push(req.query.hostname);
    const up1 = [];
    up1.push(upstreamresolvers);

    // Create the contexts we need to test with the above options.
    const context = getdns.createContext(options);
    context.upstream_recursive_servers = up1;
    context.timeout = 10000;
    context.tls_authentication = getdns.AUTHENTICATION_HOSTNAME;
    //g context.upstream_recursive_servers = resolver;
    context.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const context1 = getdns.createContext(options);
    context1.upstream_recursive_servers = up1;
    context1.timeout = 10000;
    context1.tls_authentication = getdns.AUTHENTICATION_NONE;
    context1.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const porttcp = 53;
    const upstreamresolvertcp = [];
    upstreamresolvertcp.push(resolver);
    upstreamresolvertcp.push(porttcp);
    const up2 = [];
    up2.push(upstreamresolvertcp);
    const context2 = getdns.createContext(options);
    context2.upstream_recursive_servers = up2;
    context2.timeout = 10000;
    context2.tls_authentication = getdns.AUTHENTICATION_NONE;
    context2.dns_transport = getdns.TRANSPORT_TLS_FIRST_AND_FALL_BACK_TO_TCP_KEEP_CONNECTIONS_OPEN;

"8.8.8.8",
    ],
    // Always return dnssec status.
    return_dnssec_status: true,
};

// Create the context with the above options.
// When done with a context, it must be explicitly destroyed, for example in a callback.
const context = getdns.createContext(options);

// Getdns general.
// Third argument may be a dictionary for extensions.
// Last argument must be a callback.
// Returns a transaction id, which may be used to cancel the request.
/* eslint-disable no-unused-vars */
const transactionId = context.general("labs.verisigninc.com", getdns.RRTYPE_A, generalCallback);
/* eslint-enable no-unused-vars */

// Cancel a request.
//context.cancel(transactionId);

// Other getdns context methods.
// NOTE: don't destroy context in callback so it can be reused.
// Extensions are passed as dictionaries where the value for on/off are normal booleans.
context.address("nlnetlabs.nl", { dnssec_return_only_secure: true }, addressCallback);
context.service("dnssec-name-and-shame.com", serviceCallback);
context.hostname("8.8.8.8", hostnameCallback);

process.on("beforeExit", () => {
    // NOTE: remember to explicitly destroy the context after being done with lookups.
    context.destroy();
});

upstreamresolvers.push(req.query.hostname);
    const up1 = [];
    up1.push(upstreamresolvers);

    // Create the contexts we need to test with the above options.
    const context = getdns.createContext(options);
    context.upstream_recursive_servers = up1;
    context.timeout = 10000;
    context.tls_authentication = getdns.AUTHENTICATION_HOSTNAME;
    //g context.upstream_recursive_servers = resolver;
    context.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const context1 = getdns.createContext(options);
    context1.upstream_recursive_servers = up1;
    context1.timeout = 10000;
    context1.tls_authentication = getdns.AUTHENTICATION_NONE;
    context1.dns_transport = getdns.TRANSPORT_TLS_ONLY_KEEP_CONNECTIONS_OPEN;

    const porttcp = 53;
    const upstreamresolvertcp = [];
    upstreamresolvertcp.push(resolver);
    upstreamresolvertcp.push(porttcp);
    const up2 = [];
    up2.push(upstreamresolvertcp);
    const context2 = getdns.createContext(options);
    context2.upstream_recursive_servers = up2;
    context2.timeout = 10000;
    context2.tls_authentication = getdns.AUTHENTICATION_NONE;
    context2.dns_transport = getdns.TRANSPORT_TLS_FIRST_AND_FALL_BACK_TO_TCP_KEEP_CONNECTIONS_OPEN;

    res1 += "<h1>Check TLS at Recursive</h1>";

const getFirstSecureResponse = (result, type) => {
    const repliesTree = result.replies_tree;
    // Validate that there is a reply with an answer.
    if (!repliesTree || !repliesTree.length
        || !repliesTree[0].answer
        || !repliesTree[0].answer.length) {
        return "empty answer list for type " + type;
    }
    const reply = repliesTree[0];

    // Ensure the reply is secure.
    if (reply.dnssec_status !== getdns.DNSSEC_SECURE) {
        return "insecure reply for type " + type;
    }
    let answers = reply.answer;

    // Get the records of that type.
    answers = answers.filter((answer) => {
        return answer.type === type;
    });
    if (!answers.length) {
        return "no answers of type " + type;
    }
    return answers[0];
};