2020-04-25

|

2020-09-22

| develop

| 2 Comments

|

For develop some internal tools.

reference docs

pyvenv

Recommend to use pyvenv to develop flask, easy to manage the python version and packages

• https://docs.python.org/3/library/venv.html#module-venv

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python3 -m venv /path/to/new/virtual/environment

source /path/to/new/virtual/environment

install flask

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# under virtual env
pip install Flask

pip install flask-appbuilder

flask fab create-app

flask run

SQLAlchemy

Sometimes, if it’s not easy to add constriant condition on model.py in database level, we can try from application level by built-in methods pre_add https://flask-appbuilder.readthedocs.io/en/latest/api.html#flask_appbuilder.baseviews.BaseCRUDView.pre_add

security

Put sensitive data in file .env

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SECRET_KEY=secret key

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import os

secret_key = os.getenv("SECRET_KEY","default value")

issue

• Use JSON
• UNIQUE Index by UniqueConstraint https://stackoverflow.com/questions/10059345/sqlalchemy-unique-across-multiple-columns
• One issue in update row https://github.com/dpgaspar/Flask-AppBuilder/issues/1397
• has_key dict check key
• if there is error in log.info( error program ), console will not show that

• error example: finally is None

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  def cut_string(s: str) -> str:
    begin = s.find(",")
    end = s.rfind(",")
    s = s[begin + 1:end]
  
  if len(s) > 255:
      cut_string(s)
    else:
      return s
  

• flake8 complains on boolean comparison “==” in filter clause sqlalchemy query condition is false