09 - Reusable apps

Reusable apps

1. First, create a parent directory for polls, outside of your Django project. Call this directory django-polls.

2. Move the polls directory into the django-polls directory.

3. Create a file django-polls/README.rst with the following contents

   # django-polls/README.rst
   =====
   Polls
   =====
   
   Polls is a simple Django app to conduct Web-based polls. For each
   question, visitors can choose between a fixed number of answers.
   
   Detailed documentation is in the "docs" directory.
   
   Quick start
   -----------
   
   1. Add "polls" to your INSTALLED_APPS setting like this::
   
       INSTALLED_APPS = [
           ...
           'polls',
       ]
   
   2. Include the polls URLconf in your project urls.py like this::
   
       path('polls/', include('polls.urls')),
   
   3. Run `python manage.py migrate` to create the polls models.
   
   4. Start the development server and visit http://127.0.0.1:8000/admin/
   to create a poll (you'll need the Admin app enabled).
   
   5. Visit http://127.0.0.1:8000/polls/ to participate in the poll.
   

4. Create a django-polls/LICENSE file. Choosing a license is beyond the scope of this tutorial, but suffice it to say that code released publicly without a license is useless. Django and many Django-compatible apps are distributed under the BSD license; however, you’re free to pick your own license. Just be aware that your licensing choice will affect who is able to use your code.

5. Next we’ll create a setup.py file which provides details about how to build and install the app. A full explanation of this file is beyond the scope of this tutorial, but the setuptools docs have a good explanation. Create a file django-polls/setup.py with the following contents:

   # django-polls/setup.py
   import os
   from setuptools import find_packages, setup
   
   with open(os.path.join(os.path.dirname(__file__), 'README.rst')) as readme:
       README = readme.read()
   
   # allow setup.py to be run from any path
   os.chdir(os.path.normpath(os.path.join(os.path.abspath(__file__), os.pardir)))
   
   setup(
       name='django-polls',
       version='0.1',
       packages=find_packages(),
       include_package_data=True,
       license='BSD License',  # example license
       description='A simple Django app to conduct Web-based polls.',
       long_description=README,
       url='https://www.example.com/',
       author='Your Name',
       author_email='yourname@example.com',
       classifiers=[
           'Environment :: Web Environment',
           'Framework :: Django',
           'Framework :: Django :: X.Y',  # replace "X.Y" as appropriate
           'Intended Audience :: Developers',
           'License :: OSI Approved :: BSD License',  # example license
           'Operating System :: OS Independent',
           'Programming Language :: Python',
           'Programming Language :: Python :: 3.5',
           'Programming Language :: Python :: 3.6',
           'Topic :: Internet :: WWW/HTTP',
           'Topic :: Internet :: WWW/HTTP :: Dynamic Content',
       ],
   )
   

6. Only Python modules and packages are included in the package by default. To include additional files, we’ll need to create a MANIFEST.in file. The setuptools docs referred to in the previous step discuss this file in more details. To include the templates, the README.rst and our LICENSE file, create a file django-polls/MANIFEST.in with the following contents

   django-polls/MANIFEST.in
   include LICENSE
   include README.rst
   recursive-include polls/static *
   recursive-include polls/templates *
   

7. It’s optional, but recommended, to include detailed documentation with your app. Create an empty directory django-polls/docs for future documentation. Add an additional line to django-polls/MANIFEST.in:

   recursive-include docs *
   

8. Try building your package with python setup.py sdist (run from inside django-polls). This creates a directory called dist and builds your new package, django-polls-0.1.tar.gz.

9. Using your own package

   $ pip install --user django-polls/dist/django-polls-0.1.tar.gz
   $ pip uninstall django-polls
   

10. Publishing your app

• Email the package to a friend.
• Upload the package on your website.
• Post the package on a public repository, such as the Python Package Index (PyPI). packaging.python.org has a good tutorial for doing this.