Preparations

Start with an empty folder and create files alongside with the tutorial. If you want the full source code in advance or for comparison, check out the demo source.

Project structure

At the end of the tutorial, this project’s structure should look very similar to other Python based web projects:

.
├── aiohttpdemo_polls
│   ├── static
│   │   ├── images
│   │   │   └── background.png
│   │   └── style.css
│   ├── templates
│   │   ├── 404.html
│   │   ├── 500.html
│   │   ├── base.html
│   │   ├── detail.html
│   │   ├── index.html
│   │   └── results.html
│   ├── db.py
│   ├── __init__.py
│   ├── __main__.py
│   ├── main.py
│   ├── middlewares.py
│   ├── routes.py
│   ├── settings.py
│   ├── utils.py
│   └── views.py
├── config
│   ├── polls_test.yaml
│   └── polls.yaml
├── tests
│   ├── conftest.py
│   ├── __init__.py
│   └── test_integration.py
├── init_db.py
├── Makefile
├── README.rst
├── requirements.txt
├── setup.py
└── tox.ini

Environment

We suggest you to create an isolated Python virtual environment:

$ python3 -m venv env
$ source env/bin/activate

During the tutorial, you will be instructed to install some packages inside this activated environment. For example, you will use $ pip install aiopg to install aiopg before doing the database related sections.

Note

If you decided to run the application from the repo’s source code, install the app and its requirements:

$ cd demos/polls
$ pip install -e .

Check your Python version (tutorial requires Python 3.5 or newer):

$ python -V
Python 3.7.3

Install aiohttp

$ pip install aiohttp

Check the aiohttp version:

$ python3 -c 'import aiohttp; print(aiohttp.__version__)'
3.5.4

Database

Running server

We could have created this tutorial based on a local sqlite solution, but sqlite is almost never used in real-world applications. To better reflect a production example, we decided to use Postgres for the tutorial.

Install and run the PostgreSQL database server: http://www.postgresql.org/download/. To use PostgreSQL in a more isolated way, you may use Docker as an alternative:

$ docker run --rm -it -p 5432:5432 postgres:10

Initial setup

We need to create a running database and a user with write access. For these and other database related actions, consider one of the following options:

  • prepare manually using the database’s interactive prompt

  • prepare and execute .sql files

  • use migration tool

  • use default database/user postgres

Whichever option you choose, make sure you remember the corresponding values to put them into a config file. Here are example commands to run manually

$ psql -U postgres -h localhost
> CREATE DATABASE aiohttpdemo_polls;
> CREATE USER aiohttpdemo_user WITH PASSWORD 'aiohttpdemo_pass';
> GRANT ALL PRIVILEGES ON DATABASE aiohttpdemo_polls TO aiohttpdemo_user;

Use the psql commands, \l and \du, to check results.

Note

If you decided to run the application from the repo’s source code, this script ( init_db.py ) will create a database and running server, as well as create tables and populate them with sample data

$ python init_db.py