tmpl-flask/flaskapp/errors.py

"""Flask app error handlers"""

from pathlib import Path

from flask import Flask
from flask import render_template

from . import routes

# Add other HTTP error codes here
CODES = [404, 500]


class RouteErrors(routes.Routes):
    """Error handlers wrapped in Routes interface"""

    def __init__(self, app: Flask) -> None:

        super().__init__(app)

        tmpl_dir = self.app.template_folder
        if tmpl_dir is None:
            return

        self.tmpl = Path(__file__).parent / tmpl_dir

    def add_routes(self) -> None:
        """Add all error handlers"""

        for code in CODES:
            self.add_handler(code)

    def add_handler(self, code: int) -> None:
        """Add Flask app error handler.
        Only for internal use

        Args:
            code (int): HTTP error code
        """

        file = f'{code}.html'

        if (self.tmpl / file).exists():

            @self.app.errorhandler(code)
            def handler(_e):
                return render_template(file), code