django-debugtools

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:

.. code-block:: python

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:

.. code-block:: python

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 %}``:

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/print-original.png
   :width: 959px
   :height: 166px

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

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/template-context.png
   :width: 744px
   :height: 569px


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',
    )

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/debug-toolbar.png
   :width: 887px
   :height: 504px

|

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:

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/firebug-xview.png
   :width: 811px
   :height: 41px

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:

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/print-original.png
   :width: 959px
   :height: 166px

|

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/inline_admin_formset.png
   :width: 959px
   :height: 208px

|

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/inline_admin_form.png
   :width: 959px
   :height: 355px

|

.. image:: https://github.com/edoburu/django-debugtools/raw/master/docs/images/adminform.form.name.png
   :width: 959px
   :height: 352px

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

.. _django-debug-toolbar: https://github.com/django-debug-toolbar/django-debug-toolbar