"Modern web applications are no longer standalone, monolithic codebases. Instead, they are expected to integrate with external, 3rd party applications to allow users to tap into new features, integrate with their social networks, and to easily migrate their data between systems. Many services afford these integrations by building web services that use the OAuth standard to authenticate users and allow ""secure delegated access"" on their behalf.
There are two versions of OAuth. Version 1.0 as introduced introduced in 2007, and OAuth 2.0 was released in 2012. Integrating Web Services with OAuth and PHP describes the differences between the two versions, explains the jargon associated with each, and--most importantly--provides working PHP examples for integrating with popular web services such as Twitter, Tumblr, Instagram, and others. This book also includes a primer on the HTTP protocol, highlights open-source resources for OAuth clients and servers, and discusses issues with OAuth and application security.
Written by PHP professional Matt Frost, this book is a useful resource for any developer that builds or integrates with online applications."