Windows

For the Windows operating system, we will find a compressed package with everything you need, just follow the instructions to setup web2py:

• Download all-in-one package web2py_win.zip
• Unzip
• Run (double click) web2py.exe

Mac

Installation for Mac is very similar to Windows, with a compressed package web2py_osx.zip. You just have to unzip it and run web2py.app to launch the program.

GNU/Linux

At the moment there are no packages for different distributions of GNU / Linux, since in most cases you can simply run from source because Python and the main units are usually pre-installed in these environments.

To use web2py from source, follow this steps:

• Install the dependencies (python and connectors to the database)
• Download the source code web2py_src.zip
• Uncompress
• Run python web2py.py

For Ubuntu (or Debian), open a console and run:

sudo apt-get install python-psycopg2
wget http://www.web2py.com/examples/static/web2py_src.zip
unzip web2py_src.zip
cd web2py
python web2py.py

Start

When you start web2py, it will show the splash screen while the program is loading:

Then there will be a dialog of the built-in development web server. To start the server choose and enter an administrator password (eg. 'abc') and press start:

Welcome

When the server starts, web2py will launch a browser with a default welcome page :

This page is the default application, a "skeleton" that is used when we create Web2Py applications.

Basically we have several links to the administrative interface, documentation, interactive examples and a short description about the page you are viewing:

• You visited the URL .../default/index
• Which called the function index() located in the file .../controllers/default.py
• The output of the file is a dictionary that has been rendered by the view .../views/default/index.html

Administrative Interface

Once we have web2py running and we can see the home page, we can begin to create and edit our web applications by going to the administrative interface:

On that page, you must enter the password chosen in the previous step. An index with the installed applications will be shown:

Here we can create new applications, upload or download pre-made applications, edit source code, html files, upload static files, translate messages, review the error log, etc. All these topics we will be addressed in the following articles.

In this case, we will enter the default welcome (welcome) application, by clicking the EDIT link (edit)

And once there, we can modify the main controller source code (default.py) by clicking on the edit link (edit):

The links above allow us to quickly edit the related html templates and test the exposed functionality.

We can see that the code of this hello world program is very simple, we have the index (which is run by default when entering the application), which establishes the flashing message "Welcome to web2py" and returns a dictionary with a variable message = 'Hello World' to be used to generate the webpage:

def index():
  """
  acción ejemplo usando el operador de internacionalización T y mensaje flash
  renderizado por views/default/index.html o views/generic.html
  """
  response.flash = T('Welcome to web2py')
  return dict(message=T('Hello World'))

Note that this is all the code that is used in the function to generate the web page. It is not mandatory to run management scripts, modify configuration files, map URLs with regular expressions and/or to import several modules. Web2Py take care of all these issues for us.

We will end here by now, since the idea of this article was to show a brief introduction to the tool. In later articles we will continue with more advanced topics.

For users who wish to continue experimenting with this tool, we recommend following the interactive examples at: http://www.web2py.com.ar/examples/default/examples, where small code snipes are used to show the main features of the framework.