py_flaskeleton

A skeleton for an API using Flask factory.
It follows the MVC pattern without any decorator.
This example also illustrates usage of PostgreSQL without ORM, as well as some unit tests.

Requirements

• postgresql
• python3-psycopg2 (from PostgreSQL repository)
• python3-flask
• python3-pycryptodome
• python3-scrypt
• python3-coverage (optional, for coverage of unit tests)

Project structure

General

.
├── src/
├── bin/
├── cli.py
├── config.template.yml
├── migration/
└── web.py

• src/ is the application itself, structure is detailed in next section
• bin/ contains bash wrappers to run CLI and API
• migration/ contains db schemas in raw SQL format
• cli.py and web.py instantiate the application accordingly
• config.template.yml must be copied somewhere as config.yml and will contain app/db/logger parameters

By default, bash wrappers assume config.yml being at the root of the project.
This can be changed by specifying/exporting the environment variable FLASKLELETON_CONFIG before the command.

The application

src/
├── action
├── bo
├── cli
├── converter
├── crypto
├── entity
├── include
├── __init__.py
├── middleware
├── service
├── table
├── template
└── validator

Path	Purpose
__init__.py	app bootstrap: inject dependencies, register services/routes/cli
include/	define app components: API routing, CLI commands, services to build the application
middleware/	implement pre-processing applied automatically on requests before controllers (eg. authorization)
action/	implement controllers as defined in routing.py. usually validate inputs then delegate to bo
cli/	implement commands as defined in clis.py
bo/	implement the logic to process requests and prepare the response
table/	implement database operations
entity/	map database tables as object
template/	encapsulate common formatting like responses
service/	implement global services (DB connector, logger, error handler, depency injection)
crypto/	centralize encryption and hashing needs
validator/	centralize user inputs validation
converter/	centralize needs for type conversion (eg. datetime)

Local run

DB creation

• create db and user, and complete config.yml accordingly.

$ sudo -u postgres createuser -h localhost -p 5432 --pwprompt my_user
$ sudo -u postgres createdb -h localhost -p 5432 -O my_user --encoding='utf-8' my_db 

• create db schema. From root:

$ bash bin/cli.sh dev db_migration init
$ bash bin/cli.sh dev db_migration check
$ bash bin/cli.sh dev db_migration apply

To connect to the db:

$ psql -U my_user -h localhost -p 5432 my_db

Run application

From project root:

• API: bash bin/web.sh dev
• CLI: bash bin/cli.sh dev --help

Run tests

From root:

$ python3 -m runner_tests
$ python3 -m coverage run runner_tests.py
$ python3 -m coverage report