Quick Flask API Demo implementing a checkout endpoint. See tests/api_test.sh for example usage.
Install Python 3.7 or newer from https://www.python.org/downloads/
Install Flask as described at https://flask.palletsprojects.com/en/2.2.x/installation/
The application can be run locally under the Flask development server by
running python -m flask run when in the watch-shop directory
Most tests are implemented in Python's UnitTest framework and are in test_<module-name>.py files within the same directory
as the modules they test. Run these from the top level directory with python -m unittest discover -v
The API proper can be exercised by starting the application and then running tests/api_test.sh
The application is structured into main 3 units, forming a dependency stack.
| Design Unit | Implementation Location | Description |
|---|---|---|
| API Routing | ./app.py |
Only module that interacts with the Flask Framework, provides marshalling of Request and Response data for the rest of the application. |
| Business Logic | ./business_logic/ |
Logic for calculating the checkout result. Only module that understands how to interpret watch data. |
| Data Layer | ./data_layer/ |
Abstraction of the data store used to provide watch data. In this implementation the data store is a CSV file |
Each unit provides an interface to the one above implemented using built in datatypes. Each module can only communicate with the layer above or below it in, simplifying dependencies. Modules should not make any assumptions about the implementations of others.
The call flow through the modules for a checkout request is as follows.
sequenceDiagram
Client->>+API Routing: JSON Request with list of Watch IDs
API Routing->>+Buisness Logic: Calculate Total Price
loop For Each Unique Watch ID
Buisness Logic->>+Data Access: Fetch Data for Watch ID
Data Access-->>-Buisness Logic: Watch Data
end
Buisness Logic-->>-API Routing: Total Price
API Routing-->>-Client: JSON Reponse with Total Price
Next steps for further development.
- API level testing
- Add logging to the application to support debug
- Add token based authentication to the API
- Enable https for encryption