Basic API Project to Python dev role at Koper

You can find the project scope at Desafio back-end PDF File in PT-Br

Tldr: API should return minimum route between two points, previously inserted, and how much it costs.

Project Stack

I choose use minimum possible external libs, so in this project I only used Django with Django Rest Framework because they allow me a fast development and didn't need to worry with database configuration for example. So for this I didn't use pytest(my preference) or a lib to resolve the Graph problem.

For development and tests I used PyCharm, Postman and DRF Browsable API in Elementary OS (Ubuntu based)

Project Setup

Python 3.6 - was the default in my system Virtualenv

Clone project

git clone git@github.com:matheusads/koper_tech_challenge.git

Make a virtualenv with at least Python 3.6

python3 -m venv venv

Activate virtualenv

source venv/bin/activate

Install dependencies

pip install -r requirements.txt

Make migrations

python manage.py makemigrations
python manage.py migrate

Create a superuser.

python manage.py creatersuperuser

Then finally run server

python manage.py runserver

Unit tests

python manage.py test

API usage

As this is a small POC, to insert data we can use Browsable API, Django Admin or APIs requests as in Postman Collection (recommended). For lot of data I would make a management script

We need to add some points(vertexes) to a map(graph) and connect(edges) the points.

At /vertex POST should send through body request some data like this {'name': 'A', graph_id: 'Map Name'}
Name: A string field with 10 characters max length. This will be a place in map.
Graph_ID: A string field with 20 characters max length. This will be the 'map name'

At /edge POST should send some like this {'source_id': 'A', 'destination_id': 'B', 'weight': 10, 'graph_id': 'Map Name'}

Source_id and Destination_id: The names of two connected points. Char Field 10 max length.
Graph_ID: Same as /vertex
Weight: Integer field, is the 'distance' between these two points.

I didn't add unit tests for these endpoints because is a 'simply' code of DRF. Just put to have Browsable APIs and fast way to add data. But have some test in Postman json file.

The most important part

At /routes we only have GET method and need send the follow query params {'map': 'Mapa SP', 'source': 'A', 'dest': 'D', 'range': 10, 'price': 2.5 }

Map, source and dest is the previously graph_id, source_id(vertex name) and destination_id(second vertex name).
Range is the range average car capacity per liters. Decimal field, so can pass almost any type of number.
Price is the fuel's value per liter. Also Decimal field. All these fields are required and validate.

This endpoint has three possible responses.

• ValidationError, raised if some field of query not in the right format or missing.
• AssertionError, a formated Response if some Point(source ou dest) not in given Map.
• The expected Response with given points, the distance and path between them, e the cost to go through.

A possible response is: "A -> D: distance = 25, path = ['A', 'B', 'D'], cost = 6.25"

PS:

To resolve the minimum distance problem I use Dijkstra Algorithm.

I choose code readability so the Graph, Vertex and Edge representations could be more simple and fast, but thinking in who will read I opt for this way.

For the sake of simplicity of these project I also didn't use git branches. My commits have a lot of code too. In real case it should be with small pieces of code.