In this book, you will learn how to build complete Django projects, ready for production use. In case you haven't installed Django yet, you will learn how to do it in the first part of this chapter. This chapter will cover how to create a simple blog application using Django. The purpose of the chapter is to get a general idea of how the framework works, understand how the different components interact with each other, and give you the skills to easily create Django projects with basic functionality. You will be guided through the creation of a complete project without elaborating upon all the details. The different framework components will be covered in detail throughout the following chapters of this book.
This chapter will cover the following points:
- Installing Django and creating your first project
- Designing models and generating model migrations
- Creating an administration site for your models
- Working with QuerySet and managers
- Building views, templates, and URLs
- Adding pagination to list views
- Using Django class-based views
If you have already installed Django, you can skip this section and jump directly to Creating your first project. Django comes as a Python package and thus can be installed in any Python environment. If you haven't installed Django yet, here is a quick guide to installing Django for local development.
Django works well with Python versions 2.7 or 3. In the examples of this book, we are going to use Python 3. If you're using Linux or Mac OS X, you probably have Python installed. If you are not sure if Python is installed in your computer, you can verify it by typing python in the terminal. If you see something like the following, then Python is installed in your computer:
Python 3.5.0 (v3.5.0:374f501f4567, Sep 12 2015, 11:00:19) [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>>
If your installed Python version is lower than 3, or Python is not installed on your computer, download Python 3.5.0 from http://www.python.org/download/ and install it.
Since you are going to use Python 3, you don't have to install a database. This Python version comes with the SQLite database built-in. SQLite is a lightweight database that you can use with Django for development. If you plan to deploy your application in a production environment, you should use an advanced database such as PostgreSQL, MySQL, or Oracle. You can get more information about how to get your database running with Django in https://docs.djangoproject.com/en/1.8/topics/install/#database-installation.
It is recommended that you use virtualenv to create isolated Python environments, so you can use different package versions for different projects, which is far more practical than installing Python packages system wide. Another advantage of using virtualenv is that you won't need any administration privileges to install Python packages. Run the following command in your shell to install virtualenv:
pip install virtualenv
After you install virtualenv, create an isolated environment with the following command:
virtualenv my_env
This will create a my_env/ directory including your Python environment. Any Python libraries you install while your virtual environment is active will go into the my_env/lib/python3.5/site-packages directory.
If your system comes with Python 2.X and you installed Python 3.X, you have to tell virtualenv to use the latter. You can locate the path where Python 3 is installed and use it to create the virtual environment with the following commands:
zenx$ *which python3* /Library/Frameworks/Python.framework/Versions/3.5/bin/python3 zenx$ *virtualenv my_env -p /Library/Frameworks/Python.framework/Versions/3.5/bin/python3*
Run the following command to activate your virtual environment:
source my_env/bin/activate
The shell prompt will include the name of the active virtual environment enclosed in parentheses, like this:
(my_env)laptop:~ zenx$You can deactivate your environment anytime with the deactivate command.
You can find more information about virtualenv at https://virtualenv.pypa.io/en/latest/.
On top of virtualenv, you can use virtualenvwrapper. This tool provides wrappers that make it easier to create and manage your virtual environments. You can download it from http://virtualenvwrapper.readthedocs.org/en/latest/.
pip is the preferred method for installing Django. Python 3.5 comes with pip pre-installed, but you can find pip installation instructions at https://pip.pypa.io/en/stable/installing/. Run the following command at the shell prompt to install Django with pip:
pip install Django==1.8.6
Django will be installed in the Python site-packages/ directory of your virtual environment.
Now check if Django has been successfully installed. Run python on a terminal and import Django to check its version:
>>> import django >>> django.VERSION django.VERSION(1, 8, 5, 'final', 0)
If you get this output, Django has been successfully installed in your machine.
Django can be installed in several other ways. You can find a complete installation guide at https://docs.djangoproject.com/en/1.8/topics/install/.