Rocketseat's NLW event project using Python and Flask to generate barcode.

1. Create Flask project in PyCharm:

2. Install other dependencies:

• pillow
• python-barcode
• Cerberus
• pytest

3. Change app.py:

• remove route /;
• add route POST '/create_tag' which receives "product_code" and creates an image in the program folder;

4. Test route http://127.0.0.1:5000/create_tag with Postman passing {"tag path": "987-654-321"};

5. Create directories:

• from the project root: /src, /src/controllers, /src/drivers, /src/errors, /src/main, /src/main/routes, /src/main/server, /src/validators, /src/views, /src/views/http_types
• everyone must have a __init__.py file

6. Extract part of the code from app.py to

• server.py: creates app and registers Blueprints
• tag_routes.py: creates a Blueprint for the POST '/create_tag' route

7. Extract part of the create_tag function code from tag_routes.py to the files:

• src/drivers/barcode_handler.py with the BarcodeHandler class;
• src/views/tag_creator_view.py with the TagCreatorView class;
• src/controllers/tag_creator_controller.py with the TagCreatorController class;
• src/views/http_types/http_request.py with the HttpRequest class;
• src/views/http_types/http_response.py with the HttpResponse class.

8. Create a function to display an error after handling it with try except:

• src/errors/error_handler.py with handle_errors function;
• function create_tag handles exceptions with try except.

9. Add custom error and validation:

• src/errors/error_types/http_unprocessable_entity.py with class HttpUnprocessableEntityError;
• src/validators/tag_creator_validator.py with the tag_creator_validator function.

10. Create tests:

• test file names must end with _test.py;
• pytest -s -v to run all tests in the directory.