Imagine a team of developers working on a mobile app for iOS and Android and requires a RESTful Web Service to perform CRUD operations with toys. We definitely don't want to use a mock web service and we don't want to spend time choosing and configuring an ORM (short for Object-Relational Mapping). We want to quickly build a RESTful Web Service and have it ready as soon as possible to start interacting with it in the mobile app.

We really want the toys to persist in a database but we don't need it to be production-ready. Therefore, we can use the simplest possible relational database, as long as we don't have to spend time performing complex installations or configurations.

Django REST framework, also known as DRF, will allow us to easily accomplish this task and start making HTTP requests to the first...

Now, we will create a simple Toy model in Django, which we will use to represent and persist toys. Open the toys/models.py file. The following lines show the initial code for this file with just one import statement and a comment that indicates we should create the models:

from django.db import models 
 
# Create your models here. 

The following lines show the new code that creates a Toy class, specifically, a Toy model in the toys/models.py file. The code file for the sample is included in the hillar_django_restful_02_01 folder in the restful01/toys/models.py file:

from django.db import models 
 
 
class Toy(models.Model): 
    created = models.DateTimeField(auto_now_add=True) 
    name = models.CharField(max_length=150, blank=False, default='') 
    description = models.CharField(max_length=250, blank=True, default='') 
    toy_category...

Now, it is necessary to create the initial migration for the new Toy model we recently coded. We will also synchronize the SQLite database for the first time. By default, Django uses the popular self-contained and embedded SQLite database, and therefore we don't need to make changes in the initial ORM configuration. In this example, we will be working with this default configuration. Of course, we will upgrade to another database after we have a sample web service built with Django. We will only use SQLite for this example.

We just need to run the following Python script in the virtual environment that we activated in the previous chapter. Make sure you are in the restful01 folder within the main folder for the virtual environment when you run the following command:

    python manage.py makemigrations toys  

The following lines show the output...

In most modern Linux distributions and macOS, SQLite is already installed, and therefore you can run the sqlite3 command-line utility.

In Windows, if you want to work with the sqlite3.exe command-line utility, you have to download the bundle of command-line tools for managing SQLite database files from the downloads section of the SQLite webpage at http://www.sqlite.org/download.html. For example, the ZIP file that includes the command-line tools for version 3.20.1 is sqlite-tools-win32-x8 6-3200100.zip. The name for the file changes with the SQLite version. You just need to make sure that you download the bundle of command-line tools and not the ZIP file that provides the SQLite DLLs. After you unzip the file, you can include the folder that includes the command-line tools in the PATH environment variable, or you can access the sqlite3.exe command...

Our RESTful Web Service has to be able to serialize and deserialize the Toy instances into JSON representations. In Django REST framework, we just need to create a serializer class for the Toy instances to manage serialization to JSON and deserialization from JSON. Now, we will dive deep into the serialization and deserialization process in Django REST framework. It is very important to understand how it works because it is one of the most important components for all the RESTful Web Services we will build.

Django REST framework uses a two-phase process for serialization. The serializers are mediators between the model instances and Python primitives. Parser and renderers handle as mediators between Python primitives and HTTP requests and responses. We will configure our mediator between the Toy model instances and Python primitives...

We can launch our default Python interactive shell in our virtual environment and make all the Django project modules available before it starts. This way, we can check that the serializer works as expected. We will do this to understand how serialization works in Django.

Run the following command to launch the interactive shell. Make sure you are within the restful01 folder in the terminal, Command Prompt, or Windows Powershell:

python manage.py shell

You will notice a line that says (InteractiveConsole) is displayed after the usual lines that introduce your default Python interactive shell. The following screenshot shows the Django shell launched in a Windows command prompt:

Enter the following code in the Python interactive shell to import all the things we will need to test the Toy model...