Expenses Web App

Tech used: Python, Flask, SqlAlchemy, Sqlite3

Installation

1. Install python3.

2. Install poetry as package manager from here.

3. Install dependencies with poetry in a venv with poetry install

4. Start the flask server with:

   export PYTHONPATH="$PWD" && poetry run python expensesapp/app.py 
   

5. (Optional) Run the tests

   poetry run pytest 
   

Explanation

The app is divided into 3 layers.

1. The models layer is responsible for the database models stored into sqlite3.
2. The service layer is doing most of the work:
   1. It includes its own models used for validation and serialization.
   2. There are Transaction child classes for every transaction type.
   3. It has a transaction_factory responsible for converting to the proper Transaction child class.
   4. It has a _load and _save method to convert to and from DB models.
3. The controller (app) layer is used for the presentation and also parses the csv files.

Things that could be added

1. Write more tests. Unit/E2E
2. Add logging.
3. Documentation on the methods
4. Add flask error handlers and blueprints
5. Optimization
6. Chunks on the csv input file.