Welcome to "The :app:`Pyramid` Web Application 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.
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.
This book is divided into three major parts:
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.
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`.
Comprehensive reference material for every public API exposed by :app:`Pyramid`. The API documentation is organized alphabetically by module name.
The Genesis of :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.
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.