Go: Building Web Applications

Nathan Kozyra, Mat Ryer

• Publisher: Packt Publishing
• Year: 2016
• Edition: 1
• eBook ISBN:
  9781787123496
• Topic: Computer Science
• Subtopic: Web Programming
• Index: Computer Science

Build real-world, production-ready solutions by harnessing the powerful features of Go

About This Book

• An easy-to-follow guide that provides everything a developer needs to know to build end-to-end web applications in Go
• Write interesting and clever, but simple code, and learn skills and techniques that are directly transferable to your own projects
• A practical approach to utilize application scaffolding to design highly scalable programs that are deeply rooted in go routines and channels

Who This Book Is For

This book is intended for developers who are new to Go, but have previous experience of building web applications and APIs.

What You Will Learn

• Build a fully featured REST API to enable client-side single page apps
• Utilize TLS to build reliable and secure sites
• Learn to apply the nuances of the Go language to implement a wide range of start-up quality projects
• Create websites and data services capable of massive scale using Go's net/http package, exploring RESTful patterns as well as low-latency WebSocket APIs
• Interact with a variety of remote web services to consume capabilities ranging from authentication and authorization to a fully functioning thesaurus
• Explore the core syntaxes and language features that enable concurrency in Go
• Understand when and where to use concurrency to keep data consistent and applications non-blocking, responsive, and reliable
• Utilize advanced concurrency patterns and best practices to stay low-level without compromising the simplicity of Go itself

In Detail

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software. It is a statically typed language with syntax loosely derived from that of C, adding garbage collection, type safety, some dynamic-typing capabilities, additional built-in types such as variable-length arrays and key-value maps, and a large standard library.

This course starts with a walkthrough of the topics most critical to anyone building a new web application. Whether it's keeping your application secure, connecting to your database, enabling token-based authentication, or utilizing logic-less templates, this course has you covered.

Scale, performance, and high availability lie at the heart of the projects, and the lessons learned throughout this course will arm you with everything you need to build world-class solutions. It will also take you through the history of concurrency, how Go utilizes it, how Go differs from other languages, and the features and structures of Go's concurrency core. It will make you feel comfortable designing a safe, data-consistent, and high-performance concurrent application in Go.

This course is an invaluable resource to help you understand Go's powerful features to build simple, reliable, secure, and efficient web applications.

Style and approach

This course is a step-by-step guide, which starts off with the basics of go programming to build web applications and will gradually move on to cover intermediate and advanced topics. You will be going through this smooth transition by building interesting projects along with the authors, discussing significant options, and decisions at each stage, while keeping the programs lean, uncluttered, and as simple as possible.

Go: Building Web Applications

---

Table of Contents

Go: Building Web Applications

Go: Building Web Applications

Credits

Preface

What this learning path covers

What you need for this learning path

Who this learning path is for

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Module 1

1. Introducing and Setting Up Go

Installing Go

Structuring a project

Code conventions

Importing packages

Handling private repositories

Dealing with versioning

Introducing the net package

Hello, Web

Summary

2. Serving and Routing

Serving files directly

Basic routing

Using more complex routing with Gorilla

Redirecting requests

Serving basic errors

Summary

3. Connecting to Data

Connecting to a database

Creating a MySQL database

Using GUID for prettier URLs

Handling 404s

Summary

4. Using Templates

Introducing templates, context, and visibility

HTML templates and text templates

Displaying variables and security

Using logic and control structures

Summary

5. Frontend Integration with RESTful APIs

Setting up the basic API endpoint

RESTful architecture and best practices

Creating our first API endpoint

Implementing security

Creating data with POST

Modifying data with PUT

Summary

6. Sessions and Cookies

Setting cookies

Capturing user information

Creating users

Enabling sessions

Letting users register

Letting users log in

Initiating a server-side session

Creating a store

Utilizing flash messages

Summary

7. Microservices and Communication

Introducing the microservice approach

Pros and cons of utilizing microservices

Understanding the heart of microservices

Communicating between microservices

Putting a message on the wire

Reading from another service

Summary

8. Logging and Testing

Introducing logging in Go

Logging to IO

Multiple loggers

Formatting your output

Using panics and fatal errors

Introducing testing in Go

Summary

9. Security

HTTPS everywhere – implementing TLS

Preventing SQL injection

Protecting against XSS

Preventing cross-site request forgery (CSRF)

Securing cookies

Using the secure middleware

Summary

10. Caching, Proxies and Improved Performance

Identifying bottlenecks

Implementing reverse proxies

Implementing caching strategies

Using Least Recently Used

Caching by file

Caching in memory

Implementing HTTP/2

Summary

2. Module 2

1. Chat Application with Web Sockets

A simple web server

Templates

Doing things once

Using your own handlers

Properly building and executing Go programs

Modeling a chat room and clients on the server

Modeling the client

Modeling a room

Concurrency programming using idiomatic Go

Turning a room into an HTTP handler

Use helper functions to remove complexity

Creating and using rooms

Building an HTML and JavaScript chat client

Getting more out of templates

Tracing code to get a look under the hood

Writing a package using TDD

Interfaces

Unit tests

Red-green testing

Implementing the interface

Unexported types being returned to users

Using our new trace package

Making tracing optional

Clean package APIs

Summary

2. Adding Authentication

Handlers all the way down

Making a pretty social sign-in page

Endpoints with dynamic paths

OAuth2

Open source OAuth2 packages

Tell the authentication providers about your app

Implementing external logging in

Logging in

Handling the response from the provider

Presenting the user data

Augmenting messages with additional data

Summary

3. Three Ways to Implement Profile Pictures

Avatars from the authentication server

Getting the avatar URL

Transmitting the avatar URL

Adding the avatar to the user interface

Logging out

Making things prettier

Implementing Gravatar

Abstracting the avatar URL process

The authentication service and avatar's implementation

Using an implementation

Gravatar implementation

Uploading an avatar picture

User identification

An upload form

Handling the upload

Serving the images

The Avatar implementation for local files

Supporting different file types

Refactoring and optimizing our code

Replacing concrete types with interfaces

Changing interfaces in a test-driven way

Fixing existing implementations

Global variables versus fields

Implementing our new design

Tidying up and testing

Combining all three implementations

Summary

4. Command-line Tools to Find Domain Names

Pipe design for command-line tools

Five simple programs

Sprinkle

Exercise – configurable transformations

Domainify

Exercise – making top-level domains configurable

Coolify

Synonyms

Using environment variables for configuration

Consuming a web API

Getting domain suggestions

Available

Composing all five programs

One program to rule them all

Summary

5. Building Distributed Systems and Working with Flexible Data

System design

Database design

Installing the environment

NSQ

NSQ driver for Go

MongoDB

MongoDB driver for Go

Starting the environment

Votes from Twitter

Authorization with Twitter

Extracting the connection

Reading environment variables

Reading from MongoDB

Reading from Twitter

Signal channels

Publishing to NSQ

Gracefully starting and stopping

Testing

Counting votes

Connecting to the database

Consuming messages in NSQ

Keeping the database updated

Responding to Ctrl + C

Running our solution

Summary

6. Exposing Data and Functionality through a RESTful Data Web Service API

RESTful API design

Sharing data between handlers

Wrapping handler functions

API key

Database session

Per request variables

Cross-browser resource sharing

Responding

Understanding the request

A simple main function to serve our API

Using handler function wrappers

Handling endpoints

Using tags to add metadata to structs

Many operations with a single handler

Reading polls

Creating a poll

Deleting a poll

CORS support

Testing our API using curl

A web client that consumes the API

An index page showing a list of polls

A page to create a new poll

A page to show details of the poll

Running the solution

Summary

7. Random Recommendations Web Service

Project overview

Project design specifics

Representing data in code

Public views of Go structs

Generating random recommendations

Google Places API key

Enumerators in Go

Test-driven enumerator

Querying the Google Places API

Building recommendations

Handlers that use query parameters

CORS

Testing our API

Web application

Summary

8. Filesystem Backup

Solution design

Project structure

Backup package

Obvious interfaces?

Implementing ZIP

Has the filesystem changed?

Checking for changes and initiating a backup

Hardcoding is OK for a short while

The user command-line tool

Persisting small data

Parsing arguments

Listing the paths

String representations for your own types

Adding paths

Removing paths

Using our new tool

The daemon backup tool

Duplicated structures

Caching data

Infinite loops

Updating filedb records

Testing our solution

Summary

3. Module 3

1. An Introduction to Concurrency in Go

Introducing goroutines

A patient goroutine

Implementing the defer ...

Table of contents

• Go: Building Web Applications