flask-error-templating

Create Flask HTTP error handlers that use template rendering. This is a very small and simple idea but I couldn't find anything like it so I made it myself.

Installation

Install with pip install flask-error-templating.

Usage

create_http_error_handlers(app, error_pages, page_template_file, **kwargs)

Parameters

app

app is a handle to your Flask object. Need I write more?

error_pages

error_pages is a list of ErrorPage objects. It accepts three arguments: error_code, message and long_message. error_code and message are required; long_message is optional and if it is not present then it will not be rendered into the template. Note that it's possible to have some ErrorPage objects with long_message set and others without.

Example of error_pages:

error_pages = [
    ErrorPage(400, 'Bad request'),
    ErrorPage(400, 'Access is denied to this page.'),
    ErrorPage(403, 'You are forbidden to view this page.',
        'A very long message that we also want to display in the long_message field'),
    ErrorPage(404, 'The page you are looking for does not exist'),
    ErrorPage(418, 'I\'m a teapot!')
]

page_template_file

page_template_file is the filename of a HTML file in your projects templates folder. Parameters supplied to the file for template rendering are error_code, message and long_message. See the above paragraph for information on these parameters. If long_message is not present then an empty string will be rendered in its place - this allows the same template to serve pages with long message and also without.

Example of page_template_file:

<!DOCTYPE html>
<html>
    <body>
        <h1>{{ error_code }}</h1>
        <h2>{{ message }}</h2>
        <br>
        <p>{{ long_message }}</p>
    </body>
</html>

keyword arguments

Often, you will want to pass things like the name of your app to the template when it is being rendered. To allow passing this value, all keyword arguments after page_template_file will be passed to Flask's render_template() function.

Complete basic example:

from flask import *
from flask_error_templating import ErrorPage, create_http_error_handlers

app = Flask(__name__)

@app.route('/')
def homepage():
    return '<h1>Homepage</h1>'

error_pages = [
    ErrorPage(400, 'Bad request'),
    ErrorPage(400, 'Access is denied to this page.'),
    ErrorPage(403, 'You are forbidden to view this page.',
        'A very long message that we also want to display in the long_message field'),
    ErrorPage(404, 'The page you are looking for does not exist'),
    ErrorPage(418, 'I\'m a teapot!')
]
create_http_error_handlers(app, error_pages, 'http_error.html', app_name='Some testing app')

if __name__ == '__main__':
    app.run()