Hunting Heisenberg with Django Rest Framework

The idea

The idea was to create a simple platform for DEA agents, to manage information about characters from the Breaking Bad/Better Call Saul universe. To make the DEA agents’ life easier, they need to have an API endpoint that allows filtering information about characters by their name, date of birth, occupation or the fact whether they are a suspect.

As the DEA is trying to put drug lords behind bars, they are tracking them and the people around their location. They store timestamps and particular locations as geographical coordinates in a related table. The endpoint that will expose the data needs to allow filtering of location entries, that were within a specific distance from a particular geographical point, as well as who they were assigned to, and the datetime range of when they were recorded. The ordering for this endpoint should allow taking into consideration distance from a specified geographical point, both ascending and descending.

To see how it was done, you can set up this project locally by following the documentation below and testing it on your own.

You can find the code in my GitHub repository here.

Setting up the project

As prerequisites, you will need to have Docker and docker-compose installed on your system.

At first, go to your project’s folder and clone the Breaking Bad API repository:

git clone [email protected]:drangovski/breaking-bad-api.git

cd breaking-bad-api

Then you will need to create and .env file where you will put the values for the following variables:

POSTGRES_USER=heisenberg
POSTGRES_PASSWORD=iamthedanger
POSTGRES_DB=breakingbad
DEBUG=True
SECRET_KEY="<SECRET KEY>"
DJANGO_ALLOWED_HOSTS=localhost 127.0.0.1 [::1]
SQL_ENGINE=django.db.backends.postgresql
SQL_DATABASE=breakingbad
SQL_USER=heisenberg
SQL_PASSWORD=iamthedanger
SQL_HOST=db<br />
SQL_PORT=5432

Note: If you want, you can use the env_generator.sh file to create .env file for you. This will automatically generate the SECRET_KEY as well. To run this file, first, give it permission with chmod +x env_generator.sh and then run it with ./env_generator.sh

Once you have this set, you can run:

docker-compose build

docker-compose up

This will start the Django application at localhost:8000. To access the API, the URL will be localhost:8000/api.

Mock Locations

For the sake of the theme of these projects (and eventually, to make your life a bit easier :)), you can eventually use the following locations and their coordinates:

import requests
import json

url = 'http://localhost:8000/api/characters/'

headers = {'Content-Type' : "application/json"}

response = requests.get(url, headers=headers, verify=False)

if response.status_code == 200:
    data = response.json()
    print(json.dumps(data, indent=2))
else:
    print("Request failed with status code:", response.status_code)

Characters

Retrieve all characters

To retrieves all existing characters in the database.

GET /api/characters/

[
    {
        "id": 1,
        "name": "Walter White",
        "occupation": "Chemistry Professor",
        "date_of_birth": "1971",
        "suspect": false
    },
	{
        "id": 2,
        "name": "Tuco Salamanca",
        "occupation": "Grandpa Keeper",
        "date_of_birth": "1976",
        "suspect": true
    }
]

Retrieve a single character

To retrieve a single character, pass the character’s ID to the enpoint.

GET /api/characters/{id}

Create a new character

You can use the POST method to to /characters/ endpoint in order to create a new character.

POST /api/characters/

Creation parameters

You will need to pass the following parameters in the query, in order to successfully create a character:

{
	"name": "string",
	"occupation": "string",
	"date_of_birth": "string",
	"suspect": boolean
}

Character ordering

Ordering of the characters can be done by two fields as parameters: name and date_of_birth

GET /api/characters/?ordering={name / date_of_birth}

Additionally, you can add the parameter ascending with a value 1 or 0 to order the results in ascending or descending order.

GET /api/characters/?ordering={name / date_of_birth}&ascending={1 / 0}

Character filtering

To filter the characters, you can use the parameters in the table below. Case insensitive.

GET /api/characters/?name={text}

Character search

You can also use the search parameter in the query to search characters and retrieve results based on the fields listed below.

GET /api/characters/?search={text}

• name

• occupation

• date_of_birth

Update a character

To update a character, you will need to pass the {id} of a character to the URL and make a PUT method request with the parameters in the table below.

PUT /api/characters/{id}

{
	"name": "Mike Ehrmantraut",
	"occupation": "Retired Officer",
	"date_of_birth": "1945",
	"suspect": false
}

Delete a character

To delete a character, you will need to pass the {id} of a character to the URL and make DELETE method request.

DELETE /api/characters/{id}

Locations

Retrieve all locations

To retrieves all existing locations in the database.

GET /api/locations/

[
    {
        "id": 1,
        "name": "Los Pollos Hermanos",
        "longitude": 35.065442792232716,
        "latitude": -106.6444840309555,
        "created": "2023-02-09T22:04:32.441106Z",
        "character": {
            "id": 2,
            "name": "Tuco Salamanca",
            "details": "http://localhost:8000/api/characters/2"
        }
    },
]

Retrieve a single location

To retrieve a single location, pass the locations ID to the endpoint.

GET /api/locations/{id}

Create a new location

You can use the POST method to /locations/ endpoint to create a new location.

POST /api/locations/

Creation parameters

You will need to pass the following parameters in the query, to successfully create a location:

{
	"name": "string",
	"longitude": float,
	"latitude": float,
	"character": integer
}

Note: Upon creation of an entry, the Longitude and the Latitude will be converted to a PointField() type of field in the model and stored as a calculated geographical value under the field coordinates, in order for the location coordinates to be eligible for GeoDjango operations.

Location ordering

Ordering of the locations can be done by providing the parameters for the longitude and latitude coordinates for a single point, and a radius (in meters). This will return all of the locations stored in the database, that are in the provided radius from the provided point (coordinates).

GET /api/locations/?longitude={longitude}&latitude={latitude}&radius={radius}

Additionally, you can add the parameter ascending with values 1 or 0 to order the results in ascending or descending order.

GET /api/locations/?longitude={longitude}&latitude={latitude}&radius={radius}&ascending={1 / 0}

Locaton filtering

To filter the locations, you can use the parameters in the table below. Case insensitive.

GET /api/locations/?character={text}

Note: You can combine filtering parameters with ordering parameters. Just keep in mind that if you filter by any of these fields above and want to use the ordering parameters, you will always need to pass longitude, latitude and radius altogether. Additionally, if you need to use ascending parameter for ordering, this parameter can’t be passed without longitude, latitude and radius as well.

Update a location

To update a location, you will need to pass the {id} of locations to the URL and make a PUT method request with the parameters in the table below.

PUT /api/locations/{id}

{
    "id": 1,
    "name": "Los Pollos Hermanos",
    "longitude": 35.065442792232716,
    "latitude": -106.6444840309555,
    "created": "2023-02-09T22:04:32.441106Z",
    "character": {
        "id": 2,
        "name": "Tuco Salamanca",
        "occupation": "Grandpa Keeper",
        "date_of_birth": "1975",
        "suspect": true
    }
}

Delete a location

To delete a location, you will need to pass the {id} of a location to the URL and make a DELETE method request.

DELETE /api/locations/{id}