hexagonit / plone.app.dexterity

The Dexterity content type system for Plone

Table of Contents

• Introduction
• Philosophy
• Getting started
• Upgrading
• Documentation
• Mailing list
• Issue tracker
• Contributing

Introduction

Dexterity wants to make some things really easy. These are:

• Create a "real" content type entirely through-the-web without having to know programming.
• As a business user, create a schema using visual or through-the-web tools, and augment it with adapters, event handlers, and other Python code written on the filesystem by a Python programmer.
• Create content types in filesystem code quickly and easily, without losing the ability to customise any aspect of the type and its operation later if required.
• Support general "behaviours" that can be enabled on a custom type in a declarative fashion. Behaviours can be things like title-to-id naming, support for locking or versioning, or sets of standard metadata with associated UI elements.
• Easily package up and distribute content types defined through-the-web, on the filesystem, or using a combination of the two.

Philosophy

Dexterity is designed with a specific philosophy in mind. This can be summarised as follows:

Reuse over reinvention

As far as possible, Dexterity should reuse components and technologies that already exist. More importantly, however, Dexterity should reuse concepts that exist elsewhere. It should be easy to learn Dexterity by analogy, and to work with Dexterity types using familiar APIs and techniques.

Small over big

Mega-frameworks be damned. Dexterity consists of a number of specialised packages, each of which is independently tested and reusable. Furthermore, packages should have as few dependencies as possible, and should declare their dependencies explicitly. This helps keep the design clean and the code manageable.

Natural interaction over excessive generality

The Dexterity design was driven by several use cases that express the way in which we want people to work with Dexterity. The end goal is to make it easy to get started, but also easy to progress from an initial prototype to a complex set of types and associated behaviours through step-wise learning and natural interaction patterns. Dexterity aims to consider its users - be they business analysts, light integrators or Python developers, and be they new or experienced - and cater to them explicitly with obvious, well-documented, natural interaction patterns.

Real code over generated code

Generated code is difficult to understand and difficult to debug when it doesn't work as expected. There is rarely, if ever, any reason to scribble methods or 'exec' strings of Python code.

Zope 3 over Zope 2

Although Dexterity does not pretend to work with non-CMF systems, as many components as possible should work with plain Zope 3, and even where there are dependencies on Zope 2, CMF or Plone, they should - as far as is practical - follow Zope 3 techniques and best practices. Many operations (e.g. managing objects in a folder, creating new objects or manipulating objects through a defined schema) are better designed in Zope 3 than they were in Zope 2.

Zope concepts over new paradigms

We want Dexterity to be "Zope-ish". Zope is a mature, well-designed (well, mostly) and battle tested platform. We do not want to invent brand new paradigms and techniques if we can help it.

Automated testing over wishful thinking

"Everything" should be covered by automated tests. Dexterity necessarily has a lot of moving parts. Untested moving parts tend to come loose and fall on people's heads. Nobody likes that.

Getting started

Please read the installation guide to get Dexterity up and running.

Then log in to Plone, go to Site Setup, and go to the Dexterity Types control panel to get started creating content types through the web.

Or read the Dexterity developer manual to get started developing Dexterity content types on the filesystem.

This release of Dexterity is compatible with Plone 3, 4, and 4.1.

Upgrading

If you are upgrading from a previous release of Dexterity, you need to:

1. Update your buildout with the new versions (or extend the updated KGS), and re-run it.
2. Restart Zope.
3. Go to the Add-ons control panel in Plone Site Setup, and run the upgrade steps for "Dexterity Content Types" if there are any available.

Documentation

Various documentation is available:

• FAQ
• Dexterity Developer Manual
• How to create reusable behaviors for Dexterity types

The following documents are not Dexterity-specific, but will likely be useful to users of Dexterity:

• Schema-driven forms manual
• five.grok manual

Mailing list

The dexterity-development group provides a place to discuss development and use of Dexterity.

Issue tracker

Please report issues in our Google Code issue tracker.

Contributing

Most Dexterity code is owned by the Plone Foundation and maintained in the Plone svn repository. We're happy to share commit access so that you can share code with us, but first you must sign the Plone contributor agreement.

Dexterity wouldn't be possible without the hard work of a lot of people, including:

• Martin Aspeli
• Jian Aijun
• Wichert Akkerman
• Jonas Baumann
• David Brenneman
• Joel Burton
• Vincent Fretin
• Rok Garbas
• Anthony Gerrard
• Nathan van Gheem
• David Glick
• Craig Haynal
• Wouter Vanden Hove
• Jean-Michel Francois
• Jim Fulton
• Jamie Lentin
• Alex Limi
• Steve McMahon
• Jason Mehring
• Alec Mitchell
• Daniel Nouri
• Ross Patterson
• Maurits van Rees
• Lennart Regebro
• Laurence Rowe
• Israel Saeta Perez
• Hanno Schlichting
• Christian Schneider
• Carsten Senger
• Jon Stahl
• Eric Steele
• Gaudenz Steinlin
• Dorneles Tremea
• Sean Upton
• Sylvain Viollon
• Matthew Wilkes
• Matt Yoder
• Andi Zeidler
• Hector Velarde
• Giacomo Spettoli

(Please add your name if we have neglected to.)