Real-time web apps with mongodb and nodejs
I've been thinking about how to make a real-time web application using nodejs/socket.io/mongodb. The idea is pretty similar to google docs, where objects edited on a page are emitted and rerendered on all client browsers.
What is the best way to go about doing this? From what I've read I can think of 3 ways:
1) Using mongodb oplogs
Add a 'listener' to mongodb collections, rerender parts of page whenever changes are made to collection (cons: slow?)
2) Using local json
Retrieve mongodb data into json file, use fs to edit, save to mongodb and delete json when done (cons: cumbersome to have extra layer between database and actual app)
3) Using purely socket.io
Rerender without storing, save only after all changes have been made (cons: files probably not rendered correctly in all browsers)
Is there a better way to achieve this? (How does google docs work anyway?) Would really appreciate any help anyone can offer!
Answer
We built a real-time app last year, basically a tool for authors to work on the same page where they could add/remove/edit elements (text, images, videos, etc.)
What we used were:
- Node.js, with Hapi.js framework (express based)
- Socket.io
- No MongoDB but the awesome RethinkDB instead, which is real-time by default and basically uses listeners to tell you whenever something has changed. (mongoDB sucks in our opinion, we used it in the past and it feels like "never again", but that's our opinion)
- React/Redux in order to update the DOM only for elements that have changed, Angular with its both-ways wouldn't have worked well in our opinion, since several users may modify the same page at the same time and therefore re-rendering all the elements would cause to lose the focus.
And honestly, it's pretty awesome how fast it is.