1. Preface

Welcome to The Zope2 Book. This book is designed to introduce you to Zope2, an open-source web application server.

To make effective use of the book, you should know how to use a web browser and have a basic understanding of the Hyper Text Markup Language (HTML) and Uniform Resource Locators (URLs).

You don’t need to be a highly-skilled programmer in order to use Zope2, but you may find the understanding of some programming concepts (particularly in object-oriented programming) to be extremely helpful.

1.1. Preface to the 2.12 edition

This book has originally been written for Zope 2.6 back in 2002. It has been available in an almost unmodified form for the last seven years. During those many years quite a bit has happened in Zope itself and the general web market.

The 2.12 edition of this book does not try to write a new book on how-to do Zope development today. Instead it tries to update the original books content to be true and helpful again. Many of the underlying principles of Zope2 have not changed in the last years. The ZMI, security machinery, page templates and how-to use the ZCatalog are still there in an almost unmodified fashion. The general ideas behind object orientation, being Python based and the general architecture are still the same.

If you want to understand Zope2 you still need to understand how Acquisition works, even though it has been discouraged as a way to design your application logic.

One of the most notable differences between the original Zope2 approach and todays best-practices is in the way you develop applications with Zope2. The original Zope2 approach has focussed on a Through-The-Web (TTW) development model. You would create your entire application and manage your data through the same browser interface and store everything transparently in the same database. This model has worked very well in the beginning of “the web” as many dynamic websites have been rather simple and specialized projects.

Over the years websites have grown their requirements and often turned into development projects of a considerable size. Today websites are understood as applications in themselves and need an approach which is no longer compatible with the TTW approach of the early Zope2.

In this book you will still read about using the TTW approach for many of the examples. Please understand this as a way to quickly and easily learn about the underlying technologies. If you want to built an application based on top of Zope2, you are almost always better of approaching the project from the so called “file-system based approach” or using Python packages to extend Zope in a predictable way.

1.2. How the Book Is Organized

This book is laid out in the following chapters:

• Introducing Zope

  This chapter explains what Zope is and what it can do for you. You’ll also learn about the differences between Zope and other web application servers.

• Zope Concepts and Architecture

  This chapter explains fundamental Zope concepts and describes the basics about Zope’s architecture.

• Installing and Starting Zope

  This chapter explains how to install and start Zope for the first time. By the end of this chapter, you will have Zope installed and working.

• Object Orientation

  This chapter explains the concept of object orientation, which is the development methodology most often used to create Zope applications.

• Using the Zope Management Interface

  This chapter explains how to use Zope’s web-based management interface. By the end of this chapter, you will be able to navigate around the Zope object space, copy and move objects, and use other basic Zope features.

• Using Basic Zope Objects

  This chapter introduces objects, which are the most important elements of Zope. You’ll learn the basic Zope objects: content objects, presentation objects, and logic objects, and you’ll build a simple application using these objects.

• Acquisition

  This chapter introduces Acquisition, which is Zope’s mechanism for sharing site behavior and content.

• Basic Zope Scripting

  This chapter will introduce you to the basics of scripting.

• Using Zope Page Templates

  This chapter introduces Zope Page Templates, another Zope tool used to create dynamic web pages. You will learn about basic template statements that let you insert dynamic content, and how to create and edit page templates.

• Creating Basic Zope Applications

  This chapter presents several real-world examples of building a Zope application. You’ll learn how to use basic Zope objects and how they can work together to form basic applications.

• Users and Security

  This chapter looks at how Zope handles users, authentication, authorization, and other security-related matters.

• Advanced Page Templates

  This chapter goes into more depth with Zope Page Templates. You will learn all about template statements, expression types, and macros, which let you reuse presentation elements.

• Advanced Zope Scripting

  This chapter covers scripting Zope with Python. You will learn how to write business logic in Zope using tools more powerful than TAL, about the idea of scripts in Zope, and about Scripts (Python).

• Zope Services

  This chapter covers Zope objects that are considered “services,” which don’t readily fit into any of the basic “content,” “presentation,” or “logic” object groups.

• Basic DTML

  This chapter introduces DTML, the second tag-based scripting language. You’ll learn DTML syntax, its basic tags, and how to use DTML templates and scripting facilities. After reading this chapter, you’ll be able to create dynamic web pages with DTML.

• Advanced DTML

  This chapter takes a closer look at DTML. You’ll learn about DTML security, the tricky issue of how variables are looked up in DTML, advanced use of basic tags, and the myriad of special purpose tags.

• Searching and Categorizing Content

  This chapter shows you how to index and search objects with Zope’s built-in search engine: the Catalog. You’ll learn about indexing concepts, different patterns for indexing and searching, metadata, and search results.

• Relational Database Connectivity

  This chapter describes how Zope connects to external relational databases. You’ll learn about features that allow you to treat relational data as though it were Zope objects, and security and performance considerations.

• Virtual Hosting Services

  This chapter explains how to set up Zope in a “virtual hosting” environment, in which Zope sub-folders can be served as “top-level” host names. It includes examples that allow virtual hosting to be performed either “natively” or using Apache’s ‘mod_rewrite’ facility.

• Sessions

  This chapter describes Zope’s “sessioning” services, which allow Zope developers to “keep state” between HTTP requests.

• Scalability and ZEO

  This chapter covers issues and solutions for building and maintaining large web applications, and focuses on issues of management and scalability. In particular, the Zope Enterprise Option (ZEO) is covered in detail. You’ll learn about the tools and techniques needed to turn a small site into a large-scale site, servicing many simultaneous visitors.

• Managing Zope Objects Using External Tools

  This chapter explains how to use tools outside of your web browser to manipulate Zope objects.

• Maintaining Zope

  This chapter covers Zope maintenance and administration tasks, such as database “packing” and package installation.

• Appendix A: DTML Reference

  Reference of DTML syntax and commands.

• Appendix B: API Reference

  Reference of Zope object APIs.

• Appendix C: Page Template Reference

  Reference of Zope Page Template syntax and commands.

• Appendix D: Zope Resources

  Reference of “resources” which can be used to further enhance your Zope learning experience.

• Appendix E:

  DTML Name Lookup Rules Describes DTML’s name lookup rules.