import configparser
import logging
from typing import Tuple, List
from werkzeug.local import LocalProxy
from flask import current_app, jsonify
from flask.wrappers import Response
# logger object for all views to use
logger = LocalProxy(lambda: current_app.logger)
core_logger = logging.getLogger("core")
class Mixin:
"""Utility Base Class for SQLAlchemy Models.
Adds `to_dict()` to easily serialize objects to dictionaries.
"""
def to_dict(self) -> dict:
d_out = dict((key, val) for key, val in self.__dict__.items())
d_out.pop("_sa_instance_state", None)
d_out["_id"] = d_out.pop("id", None) # rename id key to interface with response
return d_out
def create_response(
data: dict = None, status: int = 200, message: str = ""
) -> Tuple[Response, int]:
"""Wraps response in a consistent format throughout the API.
Format inspired by https://medium.com/@shazow/how-i-design-json-api-responses-71900f00f2db
Modifications included:
- make success a boolean since there's only 2 values
- make message a single string since we will only use one message per response
IMPORTANT: data must be a dictionary where:
- the key is the name of the type of data
- the value is the data itself
:param data <str> optional data
:param status <int> optional status code, defaults to 200
:param message <str> optional message
:returns tuple of Flask Response and int
"""
if type(data) is not dict and data is not None:
raise TypeError("Data should be a dictionary 😞")
response = {"success": 200 <= status < 300, "message": message, "result": data}
return jsonify(response), status
def serialize_list(items: List) -> List:
"""Serializes a list of SQLAlchemy Objects, exposing their attributes.
:param items - List of Objects that inherit from Mixin
:returns List of dictionaries
"""
if not items or items is None:
return []
return [x.to_dict() for x in items]
# add specific Exception handlers before this, if needed
# More info at http://flask.pocoo.org/docs/1.0/patterns/apierrors/
def all_exception_handler(error: Exception) -> Tuple[Response, int]:
"""Catches and handles all exceptions, add more specific error Handlers.
:param Exception
:returns Tuple of a Flask Response and int
"""
return create_response(message=str(error), status=500)
def get_pg_url(file: str = "creds.ini") -> str:
"""Gets Postgres URL including credentials from specified file.
Example of File:
```
[pg_creds]
pg_url = postgresql://testusr:password@127.0.0.1:5432/testdb
```
:param file name
:returns str or None if exception failed
"""
try:
config = configparser.ConfigParser()
config.read(file)
mongo_section = config["pg_creds"]
return mongo_section["pg_url"]
except KeyError:
print(
f"Failed to retrieve postgres url. Check if {file} exists in the top directory and whether it follows the correct format. INGORE this message if you are not using {file} to store your credentials."
)
return None
