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Shows reflection/configuration to aid the development of Flask applications.

Project description

Flask-Debug is a simple WIP Flask-extension, intended solely for development. Example usage:

from flask import Flask
from flask_debug import Debug
app = Flask(__name__)

Now opening http://localhost:5000/_debug will show some information about the application, such as a list of registered views, url maps or configuration values.


Of course, this should never be enabled on a production server. If the application is not running in debug mode, the extension will refuse any interaction with the outside world.

Writing your own plugins

It’s fairly easy to ship a plugin for Flask-Debug with your own package or Flask-extension. This allows you to ship debugging tools right along with the extension.

First, create a package named flask_debug_yourname, the prefix flask_debug_ is important. Your should look somewhat like this:

# file: flask_debug_myext/

template_folder = 'templates'

def initialize_debug_ext(dbg):
    def debug_list_extensions():
        status = 'all good'

        return render_template('myext/status.html', status=status)

initialize_debug_ext() will be called with a flask.Blueprint-Object as the first parameter, onto which you can register your own routes. The route() function will automatically a menu entry (to suppress this behavior, add an argument of menu_name=None).

There are a few conventions:

  • Views in plugins should start with debug_.
  • URLs in routes should start with underscore + your extension name.
  • Inside your templates-folder, you should also create subfolder named myext for all of your templates, as the template namespace is global.

Flask-Debug ships a few base templates which you can use, which will use Flask-Bootstrap if available, or a minimal included template otherwise:

{# file: flask_debug_myext/templates/myext/status.html #}
{% extends "flask_debug/base.html" %}

{% block content %}
<h1>Status for myext</h1>
<p>Current status: {{status}}</p>
{% endblock %}

To finally load the plugin, just do:

import flask_debug_myext

in your extension. Before registering the debugging-blueprint onto the app, Flask-Debug will query sys.modules for all modules that look like Flask-Debug plugins and collect them.

You can check out the flask_debug_plugins-plugin (which lists all installed plugins) for an example.

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