miscellaneous useful Flask things

flask_error_handlers.py

"""
Flask application response handlers.

Reference: https://opensource.com/article/17/3/python-flask-exceptions
"""

from flask import Blueprint, jsonify


errors = Blueprint('errors', __name__)

class MyException(Exception):
   pass

@errors.app_errorhandler(MyException)
def handle_generic_error(error):
    """App handler for expected server errors."""
    message = [str(x) for x in error.args]
    status_code = 500
    success = False
    response = {
        'success': success,
        'error': {
            'type': error.__class__.__name__,
            'message': message
        }
    }
    return jsonify(response), status_code

@errors.app_errorhandler(Exception)
def handle_unexpected_error(error):  # pylint: disable=unused-argument
    """App handler for unexpected errors."""
    status_code = 500
    success = False
    response = {
        'success': success,
        'error': {
            'type': 'UnexpectedException',
            'message': 'An unexpected error has occurred.'
        }
    }
    return jsonify(response), status_code

flask_views.py

"""
useful routing & view functionality for Flask app
"""

import os

import flask

from my_app_name.flask_app import app

@app.route('/docs/<path:subpath>')
def docs(subpath):
    """Reroute /docs to static files in generated doc subpath"""
    if subpath == '' or subpath is None:
        subpath = 'index.html'
    return flask.send_from_directory(
        os.path.join(app.static_folder, 'my_app_name'), subpath)


@app.route('/docs', strict_slashes=False)
def docs_root():
    """Reroute to docs index"""
    return docs('')


# Helpers


def dump_html_safe_db_list(db_obj_list):
    """Get an HTML safe string representation of a list of DB objects."""
    return ', '.join(get_html_safe_db_repr(o) for o in db_obj_list)


def get_html_safe_db_repr(db_obj):
    """Get an HTML safe string representation of a DB object."""
    return convert_html_brackets(repr(db_obj))


def convert_html_brackets(s):
    """Convert repr <> brackets to HTML-plaintext-compatible [] brackets."""
    return s.replace('<', '[').replace('>', ']')