Strict Python

Strict python - adds checkers on input and output for python programs.

How do we do this? Idea is easy - when you write a docstring for a python function - you need to describe all incoming arguments, and if needed - describe a structure for each argument.

It's can be useful for web development. When we have incoming request - we need to make basic data validation on incoming data from user. If data doesn't much the described structure - we need to refuse access to this page and show error.

Small example

# Assume it's Django function in views.py that handles
# user request and returns response.

@strict
def show_user(request, response_format='HTML'):
  """Shows information about the given user.

  Args:
    request:
      POST:
        {
          user_id: int. User id.
          options: optional dict. Additional options.
            {
              additional_fields: optional list of integers.
            }
          welcome_phrase: optionsl str. Any string that will be printed before user name.
        }
    response_format: str, choice from ["JSON", "HTML", "XML"]. In which format
                     we need to return data.

  Returns:
    HttpResponse. It can be JSON/HTML/XML document inside the object.
  """
  user = get_user_by_id(request.POST['user_id'],
                        additional_fields=request.POST.get('additional_fields'))
  welcome_phrase = request.POST.get('welcome_phrase')
  if not welcome_phrase:
    welcome_phrase = "Hello"
  
  data = {'welcome_phrase': welcome_phrase, 'username': user.username}
  return render_response(data, response_format)