api_server.py

import gevent.monkey
gevent.monkey.patch_all()
from gevent.wsgi import WSGIServer
import pp
import ujson

pool = pp.PostgresConnectionPool("dbname=api-performance-challenge_development", maxsize=20)
HEAD = ('id', 'text', 'created_at', 'likes_count', 'liked')

def application(environ, start_response):
    status = '200 OK'

    likes = set(i[0] for i in pool.fetchall('SELECT post_id FROM likes WHERE user_id = 1'))
    posts = pool.fetchall('SELECT id, text, created_at, likes_count FROM posts LIMIT 100')
    body = ujson.dumps({
      'posts': [dict(zip(HEAD, p + (p[0] in likes,))) for p in posts]
    })

    headers = [
        ('Content-Type', 'application/json')
    ]

    start_response(status, headers)
    return [body]

WSGIServer(('', 8080), application).serve_forever()