Help, resources and hints

We’ve made our best to make PY4WEB simple and clean. But you know, modern web programming is a daunting task. It requires an open mind, able to jump frequently (without being lost!) from python to HTML to javascript to css and even database management. But don’t be scared, in this manual we’ll assist you side by side in this journey. And there are many other valuable resources that we’re going to show you.

Resources

This manual

This manual is the Reference Manual for py4web. It’s available online at https://py4web.com/_documentation/static/index.html, where you’ll also find the PDF and EBOOK version, in multiple languages. It written in RestructuredText and generated using Sphinx.

The Google group

There is a dedicated mailing list hosted on Google Groups, see https://groups.google.com/g/py4web. This is the main source of discussions for developers and simple users. For any problem you should face, this is the right place to search for a hint or a solution.

The Discord server

For quick questions and chats you can also use the free Discord server dedicated to py4web. You could usually find many py4web developers hanging out in the channel.

Tutorials and video

There are many tutorials and videos available. Here are some of them:

the Learn Py4Web site by Luca de Alfaro (with lots of excellent training videos)
the free video course 2020 by Luca de Alfaro at UC Santa Cruz
the py4web blog app by Andrew Gavgavian, which uses py4web to replicate the famous Corey Schafer’s tutorial series on creating a blog app in Django
the South Breeze Enterprises demo app by Jim Steil. It is built around the structure of the Microsoft Northwind database, but converted to SQLite. You can view the final result online here

The sources on GitHub

Last but not least, py4web is Open Source, with a BSD v3 license, hosted on GitHub at https://github.com/web2py/py4web. This means that you can read, study and experiment with all of its internal details by yourself.

Hints and tips

This paragraph is dedicated to preliminary hints, suggestions and tips that could be helpful to know before starting to learn py4web.

Prerequisites

In order to understand py4web you need at least a basic python knowledge. There are many books, courses and tutorials available on the web - choose what’s best for you. The python’s decorators, in particular, are a milestone of any python web framework and you have to fully understand it.

A modern python workplace

In the following chapters you will start coding on your computer. We suggest you to setup a modern python workplace if you plan to do it efficiently and safely. Even for running simple examples and experimenting a little, we strongly suggest to use an Integrated Development Environment (IDE). This will make your programming experience much better, allowing syntax checking, linting and visual debugging. Nowadays there are two free and multi-platform main choices: Microsoft Visual Studio Code aka VScode and JetBrains PyCharm.

When you’ll start to deal with more complex programs and need reliability, we also suggest to:

use virtual environments (also called virtualenv, see here for an introduction). In a complex workplace this will avoid to be messed up with other python programs and modules
use git to keep track of your program’s changes and save your changes in a safe place online (GitHub, GitLat, or Bitbucket).
use an editor with Syntax Highlighting. We highly recommend Visual Studio Code (VScode) or PyCharm.

Debugging py4web with VScode

It’s quite simple to run and debug py4web within VScode.

If you have installed py4web from source, you just need to open the main py4web folder (not the apps folder!) with VScode and add:

"args": ["run", "apps"],
"program": "your_full_path_to_py4web.py",

to the vscode launch.json configuration file. Note that if you’re using Windows the “your_full_path_to_py4web.py” parameter must be written using forward slash only, like “C:/Users/your_name/py4web/py4web.py”.

If you have instead installed py4web from pip, you need to set the launch.json file to run py4web as a module

{
  "name": "py4web apps",
  "type": "debugpy",
  "request": "launch",
  "module": "py4web",
  "args": ["run", "apps", "-D", "--watch", "lazy"]
}

Adjust the args to match your apps folder. For example, replace apps with . if you opened the apps folder itself in VSCode.

Tip

In both cases, if you should get gevent errors you have to also add "gevent": true on the launch.json configuration file.

Debugging py4web with PyCharm

In PyCharm, if you should get gevent errors you need to enable Settings | Build, Execution, Deployment | Python Debugger | Gevent compatible.

How to contribute

We need help from everyone: support our efforts! You can just participate in the Google group trying to answer other’s questions, submit bugs using or create pull requests on the GitHub repository.

If you wish to correct and expand this manual, or even translate it in a new foreign language, you can read all the needed information directly on the specific README on GitHub.

It’s really simple! Just change the .RST files in the /doc folder and create a Pull Request on the GitHub repository at https://github.com/web2py/py4web - you can even do it within your browser. Once the PR is accepted, your changes will be written on the master branch, and will be reflected on the web pages / pdf / epub at the next output generation on the branch.