joshivaibhav / Fetch-Rewards-Assessment

A simple flask web-app as part of the Fetch Rewards backend engineering assessment

Fetch Rewards Back-end Engineering Assessment

Below is the documentation for stting up, running and testing the Flask webserver.

Dependencies / Requirements

In order to run this project, you will need to install Python in your system, specifically Python3. Navigate to the Python website here and follow the instructions to install Python3 as per your platform (Windows, MacOS, etc.)

Once you have Python installed, you will need the dependencies / requirements for this project. The requirements.txt file contains the libraries that you will need. Pip is a popular command that is used to install packages in Python. Open the terminal and run the command below :-

pip install -r requirements.txt

Running this project

Once you have the requirements installed, navigate to the project folder and open up the terminal. Fire up the flask server by typing the below command:

python api_server.py

You should see an output as below :-

*  Serving Flask app "api_server" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 414-182-867
 * Running on http://127.0.0.1:5000/

The server is up and running at http:\127.0.0.1:5000/. Now its time to test the API and view the responses.

REST API Specifications

The following table shows the different API endpoints and their specifications.

API endpoint	Body Parameters	Methods Allowed	Body / Payload Type	End_point description
/add_points	'payer', 'points', 'transaction_timestamp'	POST	JSON	Add payer points to user account
/deduct_points	'points_to_deduct'	DELETE	JSON	deduct points from the user account
/get_balance	None	GET	No payload	retrieve the points balance in the user account

Testing the API

Once you start the flask server, you can then test the API by running the test_api_server script :-

python test_api_server.py

Viewing the response

There are number of ways to view the response of the API endpoint. You can either use the terminal go for a convenient API client like Postman. Examples for both are provided below.

1) Using the 'curl' command

Curl is a very handy command to fire HTTP requests from the command-line / terminal.

---> Add points to user account (/add_points)

Request

  Method = `POST`
  Parameters = `payer`, `points`, `transaction_timestamp` 
  Content-Type = `application/json`

Command (Windows):

curl -i -X POST -H "Content-Type: application/json" --data "{\"payer\": \"UNILIVER\", \"points\":\"200\", \"transaction_timestamp\": \"02/04 5PM\"}" http://127.0.0.1:5000/add_points

Command (Linux, Mac):

curl -i -X POST -H 'Accept: application/json' -d "{"payer": "UNILIVER", "points":"200", "transaction_timestamp": "02/04 5PM"}" http://localhost:5000/add_points/

Response

Successfully added points to the user's account

Headers

HTTP/1.0 200 OK
Content-type: application/json
Content-Length: 47
Server: Werkzeug/1.0.1 Python/3.6.8
Date: Sun, 07 Feb 2021 18:40:11 GM

---> Deduct points from user account (/deduct_points)

Request

  Method = `DELETE`
  Parameters = `points_to_deduct`
  Content-Type = `application/json`

Command (Windows):

curl -i -X DELETE -H "Content-Type: application/json" --data "{\"points-to_deduct\": \"5000\"}" http://127.0.0.1:5000/deduct_points

Command (Linux, Mac):

curl -i -X DELETE -H "Content-Type: application/json" -d "{"points-to_deduct": "5000"}" http://127.0.0.1:5000/deduct_points

Response

[["DANNON",-100,"now"],["UNILEVER",-200,"now"],["MILLER COORS",-4700,"now"]]

Headers

HTTP/1.0 200 OK
Content-type: application/json
Content-Length: 35
Server: Werkzeug/1.0.1 Python/3.6.8
Date: Sun, 07 Feb 2021 18:40:11 GM

---> Get points balance (/get_balance)

Request

  Method = `GET`
  Content-Type = `**application/json**`

Command (Windows):

curl -i -H "Content-Type: application/json" http://127.0.0.1:5000/get_balance

Command (Linux, Mac):

curl -i -H "Content-Type: application/json" http://127.0.0.1:5000/get_balance

Response

  {
     "DANNON":1000,
     "MILLER COORS":5300,
     "UNILEVER":0
   }

Headers

HTTP/1.0 200 OK
Content-type: application/json
Content-Length: 35
Server: Werkzeug/1.0.1 Python/3.6.8
Date: Sun, 07 Feb 2021 18:40:11 GM

2) Using Postman API Client

Postman is a popular API client that makes it easy for developers to create, share, test and document APIs. It can be used as a browser extension or as a native standalone app as per the platform. Install Postman from here.

---> Add points to user account (/add_points)

Request Parameters and Response

  Method = `POST`
  Parameters = `payer`, `points`, `transaction_timestamp` 
  Content-Type = `application/json`
  
  The image below shows the postman configuration for the request. The response is also shown below in the same image

---> Deduct points from user account (/deduct_points)

Request Parameters and Response

  Method = `DELETE`
  Parameters = `points_to_deduct`
  Content-Type = `application/json`
  
  The image below shows the postman configuration for the request. The response is also shown below in the same image

---> Get points balance (/get_balance)

Request Parameteres and Response

  Method = `GET`
  Content-Type = `application/json`
  
  The image below shows the postman configuration for the request. The response is also shown below in the same image

Useful Docs and References

• Flask Documentation
• Pip Installer for Python
• Postman Tutorial