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REST in Practice

Cover of REST in Practice by Ian Robinson... Published by O'Reilly Media, Inc.
  1. REST in Practice
    1. SPECIAL OFFER: Upgrade this ebook with O’Reilly
    2. Foreword
    3. Preface
      1. Should I Read This Book?
      2. Should I Skip This Book?
      3. Resources
      4. What Did You Think About the Book?
      5. Errata
      6. Conventions Used in This Book
      7. Using Code Examples
      8. How to Contact Us
      9. Safari® Books Online
      10. Acknowledgments
    4. 1. The Web As a Platform for Building Distributed Systems
      1. Architecture of the Web
      2. Thinking in Resources
      3. From the Web Architecture to the REST Architectural Style
      4. The Web As an Application Platform
      5. Web Friendliness and the Richardson Maturity Model
      6. GET on Board
    5. 2. Introducing Restbucks: How to GET a Coffee, Web Style
      1. Restbucks: A Little Coffee Shop with Global Ambitions
      2. Toolbox
      3. Here Comes the Web
    6. 3. Basic Web Integration
      1. Lose Weight, Feel Great!
      2. A Simple Coffee Ordering System
      3. URI Templates
      4. URI Tunneling
      5. POX: Plain Old XML over HTTP
      6. We Are Just Getting Started
    7. 4. CRUD Web Services
      1. Modeling Orders As Resources
      2. Building CRUD Services
      3. Aligning Resource State
      4. Consuming CRUD Services
      5. Consuming Services Automatically with WADL
      6. CRUD Is Good, but It’s Not Great
    8. 5. Hypermedia Services
      1. The Hypermedia Tenet
      2. Hypermedia Formats
      3. Contracts
      4. Hypermedia Protocols
      5. Implementing a Hypermedia Service
      6. Building the Ordering Service in Java
      7. Building the Ordering Service in .NET
      8. Ready, Set, Action
    9. 6. Scaling Out
      1. GET Back to Basics
      2. Caching
      3. Making Content Cacheable
      4. Implementing Caching in .NET
      5. Consistency
      6. Extending Freshness
      7. Stay Fresh
    10. 7. The Atom Syndication Format
      1. The Format
      2. Common Uses for Atom
      3. Using Atom for Event-Driven Systems
      4. Building an Atom Service in Java
      5. Building an Atom Service in .NET
      6. Atom Everywhere?
      7. After the Event
    11. 8. Atom Publishing Protocol
      1. Atom Publishing Protocol
      2. Implementing Order Fulfillment Using AtomPub
      3. Implementing AtomPub in .NET
      4. A Versatile Protocol
    12. 9. Web Security
      1. HTTP Security Essentials
      2. Identity and the OpenID Protocol
      3. The OAuth Protocol
      4. Service Hacks and Defenses
      5. Final Thoughts
    13. 10. Semantics
      1. Syntax Versus Semantics
      2. Structure and Representation of Information
      3. The Semantic Web
      4. Microformats
      5. Linked Data and the Web
      6. Guidance
    14. 11. The Web and WS-*
      1. Are Web Services Evil?
      2. SOAP: The Whole Truth
      3. WSDL: Just Another Object IDL
      4. Two Wrongs Don’t Make a Right
      5. Secure, Reliable, Transacted
      6. A Requiem for Web Services?
    15. 12. Building the Case for the Web
      1. No More Silver Bullets
      2. Building and Running Web-Based Services
      3. No Architecture Without Measurement
      4. Selling the Web
      5. Go Forth and Build
    16. Index
    17. About the Authors
    18. Colophon
    19. SPECIAL OFFER: Upgrade this ebook with O’Reilly


Because the Web is loosely coupled, weak consistency is a feature of all web-based distributed applications. As a result of the statelessness constraint, a service has no way of notifying consumers when a resource changes. In consequence, consumers sometimes act on stale data. In an attempt to keep up-to-date, many consumers will repeatedly GET (poll) a resource representation to discover whether it has changed recently. But this strategy is only as good as the polling frequency. In general, we must assume that a consumer’s understanding of the state of a resource lags the service’s view of the same resource.

Caching only exacerbates the situation. The moment we introduce caching, we should assume that consumers will become inconsistent with services, and just deal with it. While there are several techniques for increasing the degree of consistency among consumers, caches, and services, the fact remains that different web actors will often have different copies of a resource representation.

The three techniques for improving consistency are:


Invalidation involves notifying consumers and caches of changes to resources for which they hold cached representations. With server-driven invalidation, the server must maintain a list of recipients to be contacted whenever a resource changes. This goes against the requirement that services not maintain application state.


To ensure that they have an up-to-date resource representation, consumers and caches can verify ...

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