starter-tasks

Backend Task Two

This task is to create a simple server in Python that handles GET, POST, and DELETE request methods. These methods are the basics of any CRUD application. To see a working example of this task follow the setup below.

Table of Contents

Task

You will create a CRUD application in Python using Flask, an easy way to handle HTTP commands. You will interface and perform reads, deletes, and updates with a dummy database in the form of a database.json file. Below are the following requests and their expected responses. All requests will be to the / or “root” endpoint.

Getting Started

These steps should point you in the right direction to get your environment setup.

  1. Create a GitHub repository. Clone and cd into it. 
    $ git clone https://github.com/jonathanlo411/temp.git
Cloning into 'temp'...
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (3/3), done.
$ cd temp
  2. If you do not yet have Python, install it from here. At the time of writing, I am using “Python 3.11.0”. Create a Python virtual environment using venv and activate it.
python3 -m venv venv
source venv/Scripts/activate

// Sometimes setup is different 
source venv/bin/activate
  1. Install Flask into your virtual environment. 
    pip install Flask
  2. Install the “database” JSON file and move it to the root of the project directory. You can download if from here.
  3. Create your server file. You can name it whatever you want but in this case, I use server.py.
  4. Inside your Python file, import Flask and JSON as depicted in the code block. In addition, initialize your Flask app.
# Imports
from flask import Flask, request
from json import load, dump

# Init Flask app
app = Flask(__name__)
  1. Start your Flask server and begin to edit your file using the Flask documentation. 
    flask --app <your_py_file.py> --debug run
  2. For testing use Postman to send requests and receive responses. An example is show below. postmanex

HTTP Methods

GET

The GET method will query the database and return all items. Authentication is not required.

POST

The POST method will add an additional item to the database. Authentication is required in the form of a query parameter of key. The value should be set to sample_key and if it is not, should return an error. The JSON data of the additional item to be added will be put into the body (see example below). In addition, the Content-Type in the headers should be set to application/json.

DELETE

The DELETE method will remove all entries of books with the provided title. Authentication is required in the form of a query parameter of key. The value should be set to sample_key and if it is not, should return an error. An additional query parameter of title should be present in the request. The value will be set to the target of deletion.

Failure

If any of the requests fail, there should be a JSON response as show below with the status code of 403.

// Response
{
    "success": 0,
    "message": "<method> Unsuccessful"
}

Setup of Example of Task

*Note: This is a completed version of the task and should only be used to make comparisons when confused on the task. You can also use it to test various responses against it. The example, however, is NOT something your should copy from.

  1. Clone the repository and cd into it. 
    git clone https://github.com/ucsdds3/starter-tasks-backend-2
cd starter-tasks-backend-2
  2. Create a virtual environment and activate it. In addition, install the requirements via the requirements.txt. 
    python3 -m venv venv
source venv/Scripts/activate
pip install -r requirements.txt
  3. Start the Flask server. 
    flask --app server run
  4. Use Postman or an API client of your choice to test the example methods.
This site is open source. Improve this page.