Simple RESTful service on Flask with CRUD and GIS

gisrest.py

# requirements: flask-restful

import math

from flask import Flask
from flask_restful import Resource, Api, abort, reqparse

app = Flask(__name__)
api = Api(app)

parser = reqparse.RequestParser()
parser.add_argument('name')
parser.add_argument('x', type=float)
parser.add_argument('y', type=float)

users = {}


def abort_if_user_not_exists(user_id):
    if int(user_id) not in users:
        abort(404, message='User with ID {} does not exist'.format(user_id))


class UserList(Resource):
    def get(self):
        return users

    def post(self):
        user_id = int(max(users.keys())) + 1 if len(users) > 0 else 1
        args = parser.parse_args()
        users[user_id] = {'name': args['name'], 'x': args['x'], 'y': args['y']}
        return users[user_id], 201


class User(Resource):
    def get(self, user_id):
        abort_if_user_not_exists(user_id)
        return users[user_id]

    def put(self, user_id):
        abort_if_user_not_exists(user_id)
        args = parser.parse_args()
        user = {'name': args['name'], 'x': args['x'], 'y': args['y']}
        users[user_id] = user
        return user, 201

    def delete(self, user_id):
        abort_if_user_not_exists(user_id)
        del users[user_id]
        return '', 204


class FakePostGIS(object):
    def _coord_power(self, a, b):
        value = a - b if a > b else b - a
        return math.pow(value, 2)

    def by_distance(self, user_id, value):
        user = users[user_id]
        x1, y1 = user['x'], user['y']
        result = {}
        for key, item in users.items():
            if key == user_id:
                continue
            x2, y2 = item['x'], item['y']
            xdiff = self._coord_power(x2, x1)
            ydiff = self._coord_power(y2, y1)
            distance = math.sqrt(xdiff + ydiff)
            item.update({'distance': distance})
            if value > distance:
                result[key] = item
        return result


class UserSearch(Resource):
    def __init__(self):
        self.gis = FakePostGIS()

    def get(self, user_id, distance):
        abort_if_user_not_exists(user_id)
        return self.gis.by_distance(user_id, float(distance))


api.add_resource(UserList, '/')
api.add_resource(User, '/user/<int:user_id>')
api.add_resource(UserSearch, '/search/<int:user_id>/<distance>')


if __name__ == '__main__':
    app.run(debug=True)