=====================
 Author Introduction
=====================

Welcome to "The :app:`Pyramid` Web Framework".  In this
introduction, I'll describe the audience for this book, I'll describe
the book content, I'll provide some context regarding the genesis of
:app:`Pyramid`, and I'll thank some important people.

I hope you enjoy both this book and the software it documents.  I've
had a blast writing both.

.. index::
   single: book audience

Audience
========

This book is aimed primarily at a reader that has the following
attributes:

- At least a moderate amount of :term:`Python` experience.

- A familiarity with web protocols such as HTTP and CGI.

If you fit into both of these categories, you're in the direct target
audience for this book.  But don't worry, even if you have no
experience with Python or the web, both are easy to pick up "on the
fly".

Python is an *excellent* language in which to write applications;
becoming productive in Python is almost mind-blowingly easy.  If you
already have experience in another language such as Java, Visual
Basic, Perl, Ruby, or even C/C++, learning Python will be a snap; it
should take you no longer than a couple of days to become modestly
productive.  If you don't have previous programming experience, it
will be slightly harder, and it will take a little longer, but you'd
be hard-pressed to find a better "first language."

Web technology familiarity is assumed in various places within the
book.  For example, the book doesn't try to define common web-related
concepts like "URL" or "query string."  Likewise, the book describes
various interactions in terms of the HTTP protocol, but it does not
describe how the HTTP protocol works in detail.  Like any good web
framework, though, :app:`Pyramid` shields you from needing to know
most of the gory details of web protocols and low-level data
structures. As a result, you can usually avoid becoming "blocked"
while you read this book even if you don't yet deeply understand web
technologies.

.. index::
   single: book content overview

Book Content
============

This book is divided into three major parts:

:ref:`narrative_documentation`

  This is documentation which describes :app:`Pyramid` concepts in
  narrative form, written in a largely conversational tone.  Each
  narrative documentation chapter describes an isolated
  :app:`Pyramid` concept.  You should be able to get useful
  information out of the narrative chapters if you read them
  out-of-order, or when you need only a reminder about a particular
  topic while you're developing an application.

:ref:`tutorials`

  Each tutorial builds a sample application or implements a set of
  concepts with a sample; it then describes the application or
  concepts in terms of the sample.  You should read the tutorials if
  you want a guided tour of :app:`Pyramid`.

:ref:`api_documentation`

  Comprehensive reference material for every public API exposed by
  :app:`Pyramid`.  The API documentation is organized
  alphabetically by module name.

.. index::
   single: repoze.zope2
   single: Zope 3
   single: Zope 2
   single: repoze.bfg genesis
   single: pyramid genesis

The Genesis of :mod:`repoze.bfg`
================================

Before the end of 2010, :app:`Pyramid` was known as :mod:`repoze.bfg`.

I wrote :mod:`repoze.bfg` after many years of writing applications
using :term:`Zope`.  Zope provided me with a lot of mileage: it wasn't
until almost a decade of successfully creating applications using it
that I decided to write a different web framework.  Although
:mod:`repoze.bfg` takes inspiration from a variety of web frameworks,
it owes more of its core design to Zope than any other.

The Repoze "brand" existed before :mod:`repoze.bfg` was created.  One
of the first packages developed as part of the Repoze brand was a
package named :mod:`repoze.zope2`.  This was a package that allowed
Zope 2 applications to run under a :term:`WSGI` server without
modification.  Zope 2 did not have reasonable WSGI support at the
time.

During the development of the :mod:`repoze.zope2` package, I found
that replicating the Zope 2 "publisher" -- the machinery that maps
URLs to code -- was time-consuming and fiddly.  Zope 2 had evolved
over many years, and emulating all of its edge cases was extremely
difficult.  I finished the :mod:`repoze.zope2` package, and it
emulates the normal Zope 2 publisher pretty well.  But during its
development, it became clear that Zope 2 had simply begun to exceed my
tolerance for complexity, and I began to look around for simpler
options.

I considered using the Zope 3 application server machinery, but it
turned out that it had become more indirect than the Zope 2 machinery
it aimed to replace, which didn't fulfill the goal of simplification.
I also considered using Django and Pylons, but neither of those
frameworks offer much along the axes of traversal, contextual
declarative security, or application extensibility; these were
features I had become accustomed to as a Zope developer.

I decided that in the long term, creating a simpler framework that
retained features I had become accustomed to when developing Zope
applications was a more reasonable idea than continuing to use any
Zope publisher or living with the limitations and unfamiliarities of a
different framework.  The result is what is now :app:`Pyramid`.

The Genesis of :app:`Pyramid`
=============================

What was :mod:`repoze.bfg` has become :app:`Pyramid` as the result of
a coalition built between the :term:`Repoze` and :term:`Pylons`
community throughout the year 2010.  By merging technology, we're able
to reduce duplication of effort, and take advantage of more of each
others' technology.

.. index::
   single: Bicking, Ian
   single: Everitt, Paul
   single: Seaver, Tres
   single: Sawyers, Andrew
   single: Borch, Malthe
   single: de la Guardia, Carlos
   single: Brandl, Georg
   single: Oram, Simon
   single: Hardwick, Nat
   single: Fulton, Jim
   single: Moroz, Tom
   single: Koym, Todd
   single: van Rossum, Guido
   single: Peters, Tim
   single: Rossi, Chris
   single: Holth, Daniel
   single: Hathaway, Shane
   single: Akkerman, Wichert
   single: Laflamme, Blaise
   single: Laflamme, Hugues
   single: Bangert, Ben
   single: Duncan, Casey
   single: Orr, Mike
   single: Shipman, John
   single: Beelby, Chris
   single: Paez, Patricio
   single: Merickel, Michael

Thanks
======

This book is dedicated to my grandmother, who gave me my first
typewriter (a Royal), and my mother, who bought me my first computer
(a VIC-20).

Thanks to the following people for providing expertise, resources, and
software.  Without the help of these folks, neither this book nor the
software which it details would exist: Paul Everitt, Tres Seaver, Andrew
Sawyers, Malthe Borch, Carlos de la Guardia, Chris Rossi, Shane Hathaway,
Daniel Holth, Wichert Akkerman, Georg Brandl, Blaise Laflamme, Ben Bangert,
Casey Duncan, Hugues Laflamme, Mike Orr, John Shipman, Chris Beelby, Patricio
Paez, Simon Oram, Nat Hardwick, Ian Bicking, Jim Fulton, Michael Merickel,
Tom Moroz of the Open Society Institute, and Todd Koym of Environmental
Health Sciences.

Thanks to Guido van Rossum and Tim Peters for Python.

Special thanks to Tricia for putting up with me.