iuriinedostup / flat-group-app

Group flat list of dictionaries

1. CLI application to group a list of dictionaries by provided keys
2. Simple REST API to use library

Business problem

Given flat list of dictionaries application should create a dictionary with data grouped by key. To solve this problem application uses sort by key and group by key techniques. It invokes sorting and grouping logic recursively until all keys are used.

To control CLI application there is ArgumentParser configured. For REST API flask_rest is used. The endpoint is /group?key=<key1>[&key=<key2>]

Getting Started

Follow installation steps to start using the application.

Prerequisites

• python 3.6+
• virtualenv

Installing

To install application execute make setup It will create virtual environment and install dependencies. You may also need to setup PYTHONPATH to the root of project directory.

Usage

Application can be used as:

• CLI
• REST API

CLI application

Make sure you have activated your virtual environment. To test your JSON data execute:

cat input.json | python bin/group.py currency country

You may also forward output to file.

REST API

Rest API is powered by flask-rest application. To start webserver execute:

python bin/api.py

API is available at http://localhost:5000 by default. To group data issue a POST request:

curl -X POST \
  --url 'http://localhost:5000/group?key=country&key=currency' \
  --header 'Content-Type: application/json' \
  --header 'Authorization: Basic my_secret_token' \
  --data '[{"country":"US","city":"New York","currency":"USD","amount":100},{"country":"DE","city":"Munich","currency":"EUR","amount":20},{"country":"DE","city":"Berlin","currency":"EUR","amount":11.4},{"country":"NL","city":"Amsterdam","currency":"EUR","amount":8.9},{"country":"UK","city": "London","currency":"GBP","amount": 12.2}]' 

Development

Make sure you have path to this application in your PYTHONPATH or run scripts from the project root so PYTHONPATH will be updated automatically

Tests

To run code style checker and execute tests:

make test

There are bunch of unit tests to test some application logic and execution flow. Also, there are integration tests to assert how components are being used together as real application runs.

Author

• Iurii Nedostup - [e-mail]