Example of Node.js app to replicate Hacker News Firebase feed into RethinkDB

hn-feeder.js

var firebase = require('firebase');
var r = require('rethinkdb');

firebase.initializeApp({
  "appName" : "HN News Feed",
  "databaseURL" : "https://hacker-news.firebaseio.com/"
});

var rdbconn = null;

r.connect( {host: '<your rethinkdbhost.com>', port: 28015, user: '<your rethink user>', password: '<your rethink password>'}, function(err, conn) {
        if (err) throw err;
        rdbconn = conn;
});

// Get a reference to the Top Stories feed
var newStoryRef = firebase.app().database().ref("v0/newstories");
// You can get other story feeds too - see the HN API docs for more info. (Don't forget to set up a 'watch' function (see last block of code) for each story feed you want).
// var topStoryRef = firebase.app().database().ref("v0/topstories");
// var bestStoryRef = firebase.app().database().ref("v0/beststories");

// And the changes feed
var updatesRef = firebase.app().database().ref("v0/updates");


function pullUser(currentUser) {
  // Read full story from HN
  firebase.app().database().ref("v0/user/" + currentUser).once("value").then(function(snapshot) {
    // Add it to RethinkDB
    if (snapshot.val() !== null) {
      r.db("hn_data").table("hn_users").insert(snapshot.val(), {conflict: "update"}).run(rdbconn, function(err, result) {
        if (err) throw err;
        var username = "[" + snapshot.val().id + "]";
        if (result.inserted) {
          console.log("Inserted user" + username);
        }
        if (result.replaced) {
          console.log("Replaced user" + username);
        }
      });
    }
  });
}


function pullItem(currentItem) {
  // Read full story from HN
  firebase.app().database().ref("v0/item/" + currentItem.toString()).once("value").then(function(snapshot) {
    // Add it to RethinkDB
    if (snapshot.val() !== null) {
      r.db("hn_data").table("hn_feed").insert(snapshot.val(), {conflict: "update"}).run(rdbconn, function(err, result) {
        if (err) throw err;
        if (snapshot.val().hasOwnProperty("title")) {
          var itemTitle = snapshot.val().title;
        } else {
          var itemTitle = "A comment";
        }
        if (result.inserted) {
          console.log("Inserted: " + itemTitle);
        }
        if (result.replaced) {
          console.log("Replaced: " + itemTitle);
        }
      });
    }
  });
}


// Set a watch on the changes
updatesRef.on("value", function(snap) {
  var items = snap.val().items;
  var users = snap.val().profiles;
  // Loop through the items
  for (var i = 0; i < items.length; i++) {
    pullItem(items[i]);
  } // for
  // Loop through the users
  for (var i = 0; i < users.length; i++) {
    pullUser(users[i]);
  } // for
});


// Set a watch on the top stories, and act if Firebase pushes out a change
// NOTE: You need to set up a separate 'watcher' for every story feed that you want to 'listen' to.
newStoryRef.on("value", function(snap) {
  console.log("(New Stories pushed from HN)");
  var pushData = {id: "newstories", list: snap.val()};
  r.db("hn_data").table("hn_lists").insert(pushData, {conflict: "update"}).run(rdbconn, function(err, result) {
    if (err) throw err;
  });
});