PHP Web Services (2013)

Preface

In this age, when it can sometimes seem like every system is connected to every other system, dealing with data has become a major ingredient in building the Web. Whether you will be delivering services or consuming them, web service is a key part of all modern, public-facing applications, and this book is here to help you navigate your way along the road ahead. We will cover the different styles of service—from RPC, to SOAP, to REST—and you will see how to devise great solutions using these existing approaches, as well as examples of APIs in the wild. Whether you’re sharing data between two internal systems, using a service backend for a mobile application, or just plain building an API so that users can access their data, this book has you covered, from the technical sections on HTTP, JSON, and XML to the “big picture” areas such as creating a robust service.

Why did we pick PHP for this book? Well, PHP has always taken on the mission to “solve the web problem.” Web services are very much part of that “problem” and PHP is ideally equipped to make your life easy, both when consuming external services and when creating your own. As a language, it runs on many platforms and is the technology behind more than half of the Web, so you can be sure that it will be widely available, wherever you are. This book does not adopt any particular frameworks; instead, it aims to give you the tools you will need to understand the topic as a whole and apply that knowledge to whichever frameworks, libraries, or other wrappers you choose to use.

The book walks you through everything you need to know in three broad sections. We begin by covering HTTP and the theory that goes with it, including detailed chapters on the request/response cycle, HTTP verbs and headers, and cookies. There are also chapters on JSON and XML: when to choose each data format, and how to handle them from within PHP. The second section aims to give very practical advice on working with RPC and SOAP services, with RESTful services, and on how to debug almost anything that works over HTTP, using a variety of tools and techniques. In the final section, we look at some of the wider issues surrounding the design of top-quality services, choosing what kind of service will work for your application, and determining how to make it robust. Another chapter is dedicated to handling errors and giving advice on why and how to document your API. Whether you dip into the book as a reference for a specific project, or read it in order to find out more about this area of technology, there’s something here to help you and your project to be successful. Enjoy!

Conventions Used in This Book

The following typographical conventions are used in this book:

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Used for program listings, as well as within paragraphs to refer to program elements such as variable or function names, databases, data types, environment variables, statements, and keywords.

Constant width bold

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Constant width italic

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