.gitignore

node_modules
secrets.js

package.json

{
  "name": "node-nat-ddns-cron",
  "private": true,
  "version": "0.0.0",
  "dependencies": {
    "nat-pmp": "0.0.1"
  }
}

update.js

var natpmp = require('nat-pmp');
var https = require('https');
var encode = require('querystring').encode;

// This is my linode API key, not stored in this file for obvious reasons.
var apiKey = require('./secrets').apiKey;

var client = natpmp.connect('10.0.1.1');
console.log("Looking up external IP address...");
client.externalIp(function (err, data) {
  if (err) throw err;
  // console.log("external ip", data);
  var ip = data.ip.join(".");
  console.log("Updating dns for home.creationix.com to point to %s...", ip); 
  setHost("creationix.com", "home", ip, function (err, result) {
    if (err) throw err;
    console.log("Mapping 22 on the local machine to 2222 on the nat...")
    client.portMapping({ private:22, public: 2222, ttl: 3600}, function (err, result) {
      if (err) throw err;
      console.log("Done");
      process.exit();
    });
  });
});

///////////////////////////////////////////////////////////////////////////////

function request(query, callback) {
  query.api_key = "...";
  var path = "/?" + encode(query);
  // console.log("GET https://api.linode.com" + path);
  query.api_key = apiKey;
  var path = "/?" + encode(query);
  https.request({
    host: "api.linode.com",
    path: path
  }, function (res) {
    var parts = [];
    var length = 0;
    res.on("data", function (chunk) {
      parts.push(chunk);
      length += chunk.length;
    });
    res.on("end", function () {
      res.rawBody = Buffer.concat(parts, length);
      try {
        res.body = JSON.parse(res.rawBody.toString('utf8'));
      }
      catch (err) {
        return callback(err);
      }
      var errors = res.body.ERRORARRAY;
      if (errors.length) {
        var error = errors[0];
        var err = new Error(error.ERRORMESSAGE);
        err.linodeCode = error.ERRORCODE;
        return callback(err, res);
      }
      return callback(null, res, res.body.DATA);
    });
  }).end();
}

function filter(data, query) {
  var queryKeys = Object.keys(query);
  var queryKeysLength = queryKeys.length;
  return data.filter(function (item) {
    for (var j = 0; j < queryKeysLength; j++) {
      var key = queryKeys[j];
      if (item[key] !== query[key]) {
        return false;
      }
    }
    return true;
  });
}

function getDomains(query, callback) {
  request({api_action: "domain.list"}, function (err, res, data) {
    if (err) return callback(err);
    var domains = filter(data, query);
    callback(null, domains);
  });
}

function getDomain(query, callback) {
  getDomains(query, function (err, domains) {
    if (domains.length) {
      return callback(null, domains[0]);
    }
    var err = new Error("No domain found using query " + JSON.stringify(query));
    callback(err);
  });
}

function getDomainResources(domainId, query, callback) {
  request({
    api_action: "domain.resource.list",
    DomainID: domainId
  }, function (err, res, data) {
    if (err) return callback(err);
    var resources = filter(data, query);
    callback(null, resources);
  });
}

function getDomainResource(domainId, query, callback) {
  getDomainResources(domainId, query, function (err, resources) {
    if (resources.length) {
      return callback(null, resources[0]);
    }
    var err = new Error("No resource found on domain " + domainId + " using query " + JSON.stringify(query));
    callback(err);
  });
}

function updateDomainResource(domainId, resourceId, values, callback) {
  var query = {
    api_action: "domain.resource.update",
    DomainID: domainId,
    ResourceID: resourceId
  };
  for (var key in values) {
    query[key] = values[key];
  }
  request(query, function (err, res, data) {
    if (err) return callback(err);
    callback(null, data);
  });
}

function setHost(domainName, subdomain, ip, callback) {
  getDomain({DOMAIN: domainName}, function (err, domain) {
    if (err) return callback(err);
    // console.log("domain", domain);
    var domainId = domain.DOMAINID;
    getDomainResource(domainId, {TYPE: "a", NAME: subdomain}, function (err, resource) {
      if (err) return callback(err);
      // console.log("resource", resource);
      var resourceId = resource.RESOURCEID;
      updateDomainResource(domainId, resourceId, { Target: ip }, callback);
    });
  });
}