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Hello everybody. In this article, I'll talk about building simple asynchronous projects with the Sani... Tagged with python, sanic, web.

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Hello everybody. In this article, I'll talk about building simple asynchronous projects with the Sanic framework.

<a dir="ltr" href="https://sanicframework.org/">Sanic </a>is a very flask-like open-source Python web server and web framework with more than <a dir="ltr" href="https://github.com/huge-success/sanic">10K stars </a>that's written to go fast. It allows the usage of <code dir="ltr">async/await </code>syntax added in Python 3.5 <a dir="ltr" href="https://docs.python.org/3/library/asyncio-task.html">(read more) </a>, which makes your code non-blocking and speedy.

Sanic has pretty good <a dir="ltr" href="https://sanic.readthedocs.io/en/latest/">documentation </a>and it's maintained by the community, for the community.

The goal of the project is to provide a simple way to get a highly performant HTTP server up and running that is easy to build, to expand, and ultimately to scale.

Before we start, let's install some packages and make sure that we have everything ready for the development of this project.

Note: Source code is available in my <a dir="ltr" href="https://github.com/davitovmasyan/sanic-project">github.com </a>repository. For each step, there is a corresponding commit.

<ul><li><code>Python3.6+ </code> </li><li><a dir="ltr" href="https://github.com/pypa/pipenv"><code dir="ltr">pipenv </code> </a>(you can use any other package installer) </li><li><code dir="ltr">PostgreSQL </code>(for database, can also be MySQL or SQLite) </li> </ul>

<ul><li><a dir="ltr" href="https://pypi.org/project/secure/"><code dir="ltr">secure </code> </a>is a lightweight package that adds optional security headers and cookie attributes for Python web frameworks. </li><li><a dir="ltr" href="https://pypi.org/project/environs/"><code dir="ltr">environs </code> </a>is a Python library for parsing environment variables. It allows you to store configuration separate from your code, as per <a dir="ltr" href="https://12factor.net/config">The Twelve-Factor App </a>methodology. </li><li><a dir="ltr" href="https://github.com/jamesstidard/sanic-envconfig"><code dir="ltr">sanic-envconfig </code> </a>is an extension that helps you bring command line &amp; environment variables into your Sanic config. </li><li><a dir="ltr" href="https://pypi.org/project/databases/"><code dir="ltr">databases </code> </a>is a Python package that allows you to make queries using the powerful <a dir="ltr" href="https://docs.sqlalchemy.org/en/13/core/"><code dir="ltr">SQLAlchemy </code> </a>Core expression language and provides support for PostgreSQL, MySQL, and SQLite. </li> </ul>

Let's create an empty directory and initialize an empty Pipfile there.

<code>pipenv -- python python3.6 </code>

Install all necessary packages using <code dir="ltr">pipenv </code>commands below.

<code>pipenv install sanic secure environs sanic-envconfig </code>

<code>pipenv install databases[postgresql] </code>

Choices are <code dir="ltr">postgresql </code>, <code dir="ltr">mysql </code>, <code dir="ltr">sqlite </code>.

Now let's create some files and folders where we will write our actual code.

We will use the <code dir="ltr">setup.py </code>file to make the project folder available as a package in our code.

<code>pipenv install -e . </code>

In the <code dir="ltr">.env </code>file, we'll store some global variables like the database connection URL.

<code dir="ltr">__main__.py </code>is created for making our project package executable from the command-line.

<code>pipenv run python -m project </code>

Let's do our first call in <code dir="ltr">__main__.py </code>file.

This is the beginning of our application. Now we need to create the init function inside of <code dir="ltr">main.py </code>file.

Simply creating the app from the Sanic class we can run it specifying host, port and optional debug keyword argument.

If you open <a dir="ltr" href="http://0.0.0.0:8000/">http://0.0.0.0:8000 </a>on your browser you'll see

We haven't created any routes yet, so it's fine for now. We will add some routes below.

Now we can modify the environment and settings. We need to specofy some variables in the <code dir="ltr">.env </code>file, read them, and pass to Sanic app config.

<code dir="ltr">.env </code>file.

Configuration…

<code dir="ltr">settings.py </code>file.

Please note that I've added an optional <code dir="ltr">auto_reload </code>argument which will activate or deactivate the Automatic Reloader.

Now it's time to set up a database.

One little note about the databases package before we go ahead:

databases package uses <a dir="ltr" href="https://github.com/MagicStack/asyncpg"><code dir="ltr">asyncpg </code> </a>which is an asynchronous interface library for PostgreSQL. It's pretty fast. See results below.

We will use two of Sanic's <a dir="ltr" href="https://sanic.readthedocs.io/en/latest/sanic/middleware.html#listeners"><code dir="ltr">listeners </code> </a>where we will specify database connect and disconnect operations. Here are the listeners that we are going to use:

<code dir="ltr">after_server_start </code> <code dir="ltr">after_server_stop </code>

<code dir="ltr">main.py </code>file.

Once more thing. We need to specify <code dir="ltr">DB_URL </code>in project settings and environment.

And in <code dir="ltr">settings.py </code>file.

Make sure that <code dir="ltr">DB_URL </code>is correct and your database is running. Now you can access the database using <code dir="ltr">app.db </code>. See more detailed information in the next section.

Now we have a connection to our database and we can try to do some SQL queries.

Let's declare a table in <code dir="ltr">tables.py </code>file using SQLAlchemy.

Here I assume that you already have a migrated database with a books table in it.

For creating database migrations, I recommend that you use <a dir="ltr" href="https://alembic.sqlalchemy.org/en/latest/"><code dir="ltr">Alembic </code> </a>which is a lightweight and easy-to-use tool that you can use with the SQLAlchemy Database Toolkit for Python.

Now we can use any SQLAlchemy core queries. Check out some examples below.

Now we need to set up routes. Let's go to <code dir="ltr">routes.py </code>and add a new route for books.

Of course we need to call <code dir="ltr">setup_routes </code>in <code dir="ltr">init </code>to make it work.

Requesting…

What about checking the response headers and seeing what we can add or fix there?

As you can see we need some security improvements. There are some missing headers such as <code dir="ltr">X-XSS-Protection </code>, <code dir="ltr">Strict-Transport-Security </code>… so let's take care of them using a combination of <a dir="ltr" href="https://sanic.readthedocs.io/en/latest/sanic/middleware.html#middleware"><code dir="ltr">middlewares </code> </a>and secure packages.

<code dir="ltr">middlewares.py </code>file.

Setting up middlewares in <code dir="ltr">main.py </code>file.

The result is:

Hope this small tutorial helped you to get started with Sanic. There are still many unexplored features in the Sanic framework that you can find and check out in the documentation.

Thanks for reading. Go Fast with Sanic and good luck!!!

How to make your code fast and asynchronous with Python and Sanic

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