Source code for DoubleDibz

What?

As I mentioned in the previous post, DoubleDibz was a craiglist-like community based market place website. I worked on it during my last year at UCLA but haven't maintained it since then. Now I want to open source the code since it could be useful for anyone working on similiar projects! If you are planning on building a social network on Flask, this is the project for you!

A couple highlight for the codebase

  • A large and complete Flask application serving purely as API endpoints which powers a complex Backbone application in the frontend.
  • A complete marketplace social network. This includes real-time notifications and messaging support.

The code

Come here to check out the entire source code.

What's included in the code?

Technology used
  • Flask
  • SqlALchemy + alembic for db migration
  • a bunch of Flask libraries
  • Backbone + Marionette js
  • fabric for deployment
  • celery
  • Facebook SDK for login
  • redis
  • Nginx
  • images stored on S3
Backend features
  • Purely API endpoints.
  • Chat.
  • Post create. This is pretty straitforward. The highlight here is every single photo will be resized and cropped and saved on s3. See here.
  • Comment on posts.
  • hashtags on products. So every products could have category/hashtags. Users could explore products for a specific hashtag.
  • Notification. DoubleDibz is completely social. User receives notifications when the products they subscribed to are sold or commented.
  • celery workers for notification. I may have over-engineered the system. I was originally concerned that if a product has a lot of subscribers and someone comments on that product, it doesn't make sense to send notification to every subscriber in the same web request. So I introduced celery to handle those tasks asynchronously.
  • Search. A really tricky part of the app is I have a database with product posts user created on DoubleDibz but I also have a separate server which pulls products from Facebook groups. The search aggregates results from both DBs. Paginations are supported as well.
  • caching results with redis. To optimize for read, I cached user notifications, post data, search results, and user data. The code is also setup to invalidate cache upon write.
Frontend

The frontend is the most fun part of the project. I learned so much about how to structure a semi-large scale Backbone application to support all the features I wanted to make. All the things I mentioned before has a frontend counter part. You can upload photos to create a new product, look at home feed which is an infinite feed, then search for products and categories, look at product details page. You can message the seller for a product you are interested or comment on the product. You can even comment and tag your FB friends and your friends will receive notifications on FB!

The main thing I want to mention is Chat. This is the most complex part of the system. The challenge here is that every x seconds I'm pulling new messages from the system, and given those new messages, I need to update the correct Backbone view components. This includes updating the message count and also the message thread.

Deployment
  • uwsgi configuration for the application server
  • production and staging nginx configuration
  • celery configuration
  • Fabric script for running deployment (push)

Take a look! Maybe there's something you can use right away.