Book Image

.Go Programming Blueprints - Second Edition

By : Mat Ryer
Book Image

.Go Programming Blueprints - Second Edition

By: Mat Ryer

Overview of this book

Go is the language of the Internet age, and the latest version of Go comes with major architectural changes. Implementation of the language, runtime, and libraries has changed significantly. The compiler and runtime are now written entirely in Go. The garbage collector is now concurrent and provides dramatically lower pause times by running in parallel with other Go routines when possible. This book will show you how to leverage all the latest features and much more. This book shows you how to build powerful systems and drops you into real-world situations. You will learn to develop high quality command-line tools that utilize the powerful shell capabilities and perform well using Go's in-built concurrency mechanisms. Scale, performance, and high availability lie at the heart of our projects, and the lessons learned throughout this book will arm you with everything you need to build world-class solutions. You will get a feel for app deployment using Docker and Google App Engine. Each project could form the basis of a start-up, which means they are directly applicable to modern software markets.
Table of Contents (19 chapters)
Go Programming Blueprints Second Edition
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface

Uploading an avatar picture


In the third and final approach of uploading a picture, we will look at how to allow users to upload an image from their local hard drive to use as their profile picture when chatting. The file will then be served to the browsers via a URL. We will need a way to associate a file with a particular user to ensure that we associate the right picture with the corresponding messages.

User identification

In order to uniquely identify our users, we are going to copy Gravatar's approach by hashing their e-mail address and using the resulting string as an identifier. We will store the user ID in the cookie along with the rest of the user-specific data. This will actually have the added benefit of removing the inefficiency associated with continuous hashing from GravatarAuth.

In auth.go, replace the code that creates the authCookieValue object with the following code:

m := md5.New() 
io.WriteString(m, strings.ToLower(user.Email())) 
userId := fmt.Sprintf("%x", m.Sum...