hairball 0.1b

# Installation for development

## Prerequisites

• virtualenv

To install virtualenv a python package installer is required. This instruction will use pip.

### Ubuntu/debian installation of prerequisites

sudo apt-get install python-setuptools sudo easy_install pip

### Mac OS X installation of prerequisites

sudo easy_install pip sudo pip install virtualenv # Follow these instructions for git installation # https://help.github.com/articles/set-up-git#platform-mac

## Configure and become familiar with git

Regardless of how you installed git, please follow [these](https://help.github.com/articles/set-up-git#platform-all) instructions beginning with the section “Set Up Git” to configure your name and email combination. Also, if you are not familiar with git, please go through the [try.github.com](http://try.github.com/) tutorial.

## Check out the project and run in development mode

0. Check out the source

   git clone git@github.com:ucsb-cs-education/hairball.git

0. Create the virtual environment

   These examples use ~/.venv as the virtual environment location, however, feel free to use whatever you prefer.

   virtualenv ~/.venv/hairball

0. Load the virtual environment (Note: you will need to run this everytime you open a new terminal to run the project’s commands)

source ~/.venv/hairball/bin/activate

0. Install the package and its dependencies in development mode

   cd hairball python setup.py develop

# Developing Plugins

## Loading Plugins

The plugins for the web service are stored in the hairball/hairball/plugins folder. The association between projects and plugins is contained the attribute plugins of a project in the database. See the above section on Working with the Database for information on adding and removing projects. Note that both the webserver processes and the process_scratch_files processes need to be restarted whenever projects are modified.

## Writing Plugins

A plugin is a python class that inherits from the class hairball.plugins.PluginBase and defines at least a __init__ function, a _process function and a class doc string (a comment).

The classes that define plugins should be grouped by functionality into a single python module (.py file) and placed in the plugins folder. For example, a set of plugins dealing with scratch audio might be grouped into the file audio.py. If their class names were SpriteVolume, UniqueBeats, and VolumeReset then the plugin names would be audio.SpriteVolume, audio.UniqueBeats and audio.VolumeReset respectively.

A complete example of a simple plugin, referred to as simple.Simple (or shortened as simple when the class name is the title-cased version of the module name) is as follows:

### sample.py

from . import PluginBase

class Simple(PluginBase):

“””Produces the standard ‘Hello World’ message.”””

def __init__(self, batch):

super(Simple, self).__init__(name=’The Simple Plugin’, batch=batch)

def _process(self, scratch):

return ‘Hello World!’

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