edoburu/django-debugtools

A toolbox of small utilities to assist Django development

Introduction

The debugtools module offers some easy to use debugging utilities to assist Django development. It features:

• A template tag to print context.
• A XViewMiddleware variation to see which view and template was used to render a page.
• A panel for django-debug-toolbar to show which view and template was used to render a page.
• A jQuery debug() function.

Installation

First install the module, preferably in a virtual environment. It can be installed from PyPI:

pip install django-debugtools

Or the current folder can be installed:

pip install .

Configuration

Add the module to the installed apps:

INSTALLED_APPS += (
    'debugtools',
)

As of Django 1.9, either use {% load debugtools_tags %} or add the following to the settings:

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                # ...
            ],
           'builtins': [                                     # Add this section
                "debugtools.templatetags.debugtools_tags",   # Add this line
            ],
        },
    },
]

Or, when you use a local.py settings file:

TEMPLATES[0]['OPTIONS']['builtins'] += [
    "debugtools.templatetags.debugtools_tags",  # enables {% print %}
]

Features

Print Template Tag

In Django templates, the following code can be used:

{% print variable1 variable2 %}

This will print out the specific variables, in case of {% print original %}:

When no variables are given (e.g. {% print %}), all context variables are displayed:

The template context variables are printed in a customized pprint.pformat format, for easy reading. Note no {% load %} tag is needed; the {% print %} function is added to the template builtins for debugging convenience.

Print Queries template tag

For convenience, there is also a {% print_queries %} tag, based on http://djangosnippets.org/snippets/93/

For more sophisticated debugging, you may want to use the django-debug-toolbar for this job.

Debug Toolbar Panel

Add the following settings to your django-debug-toolbar configuration:

DEBUG_TOOLBAR_PANELS = (
    'debug_toolbar.panels.versions.VersionsPanel',
    'debug_toolbar.panels.timer.TimerPanel',
    'debug_toolbar.panels.settings.SettingsPanel',
    'debug_toolbar.panels.headers.HeadersPanel',
    'debug_toolbar.panels.request.RequestPanel',
    'debug_toolbar.panels.sql.SQLPanel',
    'debug_toolbar.panels.staticfiles.StaticFilesPanel',
    'debugtools.panels.ViewPanel',    # Add this one
    'debug_toolbar.panels.templates.TemplatesPanel',
    'debug_toolbar.panels.cache.CachePanel',
    'debug_toolbar.panels.signals.SignalsPanel',
    'debug_toolbar.panels.logging.LoggingPanel',
    'debug_toolbar.panels.redirects.RedirectsPanel',
)

jQuery debug print

Add the following to the page:

<script type="text/javascript" src="{{ STATIC_URL }}debugtools/jquery.debug.js"></script>

Now you can print the jQuery selector context to the console:

$("#foo").children('li').debug().addClass('bar');

This will print the matched <li> elements in the console, among with the current jQuery selector. Optionally, a prefix can be included in the debug() call:

$("#foo").debug("at baz: ").addClass('bar');

X-View Middleware

As alternative to the django-debug-toolbar panel, you can also add the XViewMiddleware. Add the following setting:

INTERNAL_IPS = (
    '127.0.0.1',
)

MIDDLEWARE_CLASSES += (
    'debugtools.middleware.XViewMiddleware',
)

All requests from the internal IP, or made by the admin user will have a X-View header and X-View-Template header. In the Firebug console, or Chrome web inspector, you can see which view and template handled the current request:

The alternative templates are also displayed, in case the view allows the template to be overwritten with a different name.

Print tag examples

For example, when using the following code:

{% print original %}

{% print inline_admin_formset %}

{% for inline_admin_form in inline_admin_formset %}
    {% print inline_admin_form %}
    {% print inline_admin_form.form.name %}
{% endfor %}

It prints the context values, which helps to learn a lot about the template context:

This makes it much easier to understand what the code provides to templates.