This section is intended to get Pylons up and running as fast as possible and provide a quick overview of the project. Links are provided throughout to encourage exploration of the various aspects of Pylons.

• Python 2 series above and including 2.4 (Python 3 or later not supported at

  this time)

To avoid conflicts with system-installed Python libraries, Pylons comes with a boot-strap Python script that sets up a "virtual" Python environment. Pylons will then be installed under the virtual environment.

1. Download the go-pylons.py script.

2. Run the script and specify a directory for the virtual environment to be created under:

   $ python go-pylons.py mydevenv

$ curl https://raw.githubusercontent.com/Pylons/pylons/master/scripts/go-pylons.py | python - mydevenv

$ python go-pylons.py --no-site-packages mydevenv

curl -O http://bitbucket.org/ianb/virtualenv/raw/8dd7663d9811/virtualenv.py
python virtualenv.py mydevenv
mydevenv/bin/easy_install Pylons==1.0

This will leave a functional virtualenv and Pylons installation.

Activate the virtual environment (scripts may also be run by specifying the full path to the mydevenv/bin dir):

$ source mydevenv/bin/activate

Or on Window to activate:

> mydevenv\Scripts\activate.bat

ImportError: No module named _md5

Mercurial must be installed to retrieve the latest development source for Pylons. Mercurial packages are also available for Windows, MacOSX, and other OS's.

Check out the latest code:

$ hg clone http://bitbucket.org/bbangert/pylons/

To tell setuptools to use the version in the Pylons directory:

$ cd pylons
$ python setup.py develop

The active version of Pylons is now the copy in this directory, and changes made there will be reflected for Pylons apps running.

Create a new project named helloworld with the following command:

$ paster create -t pylons helloworld

Running this will prompt for two choices:

1. which templating engine to use
2. whether to include :term:`SQLAlchemy` support

Hit enter at each prompt to accept the defaults (Mako templating, no :term:`SQLAlchemy`).

Here is the created directory structure with links to more information:

• helloworld

  • MANIFEST.in
  • README.txt
  • development.ini - :ref:`run-config`
  • docs
  • ez_setup.py
  • helloworld (See the nested :ref:`helloworld directory <helloworld_dir>`)
  • helloworld.egg-info
  • setup.cfg
  • setup.py - :ref:`setup-config`
  • test.ini

The nested helloworld directory looks like this:

• helloworld

  • __init__.py

  • config

    • environment.py - :ref:`environment-config`
    • middleware.py - :ref:`middleware-config`
    • routing.py - :ref:`url-config`

  • controllers - :ref:`controllers`

  • lib

    • app_globals.py - :term:`app_globals`
    • base.py
    • helpers.py - :ref:`helpers`

  • model - :ref:`models`
  • public
  • templates - :ref:`templates`
  • tests - :ref:`testing`
  • websetup.py - :ref:`run-config`

Run the web application:

$ cd helloworld
$ paster serve --reload development.ini

The command loads the project's server configuration file in :file:`development.ini` and serves the Pylons application.

Visiting http://127.0.0.1:5000/ when the server is running will show the welcome page.

To create the basic hello world application, first create a :term:`controller` in the project to handle requests:

$ paster controller hello

Open the :file:`helloworld/controllers/hello.py` module that was created. The default controller will return just the string 'Hello World':

import logging

from pylons import request, response, session, tmpl_context as c, url
from pylons.controllers.util import abort, redirect

from helloworld.lib.base import BaseController, render

log = logging.getLogger(__name__)

class HelloController(BaseController):

    def index(self):
        # Return a rendered template
        #return render('/hello.mako')
        # or, Return a response
        return 'Hello World'

At the top of the module, some commonly used objects are imported automatically.

Navigate to http://127.0.0.1:5000/hello/index where there should be a short text string saying "Hello World" (start up the app if needed):

Add a template to render some of the information that's in the :term:`environ`.

First, create a :file:`hello.mako` file in the :file:`templates` directory with the following contents:

Hello World, the environ variable looks like: <br />

${request.environ}

The :term:`request` variable in templates is used to get information about the current request. :ref:`Template globals <template-globals>` lists all the variables Pylons makes available for use in templates.

Next, update the :file:`controllers/hello.py` module so that the index method is as follows:

class HelloController(BaseController):

    def index(self):
        return render('/hello.mako')

Refreshing the page in the browser will now look similar to this: