6. Exposing Data and Functionality through a RESTful Data Web Service API | Go Programming Blueprints

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Go Programming Blueprints

By : Mat Ryer

4.1 (10)

Go Programming Blueprints

4.1 (10)

By: Mat Ryer

Overview of this book

Intended for seasoned Go programmers who want to put their expertise in Go to use to solve big, real-world, modern problems. With a basic understanding of channels and goroutines, you will hone your skills to build tools and programs that are quick and simple. You need not be an expert in distributed systems or technologies in order to deliver solutions capable of great scale. It is assumed that you are familiar with the basic concepts of Go.

Preface

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Free Chapter

1. Chat Application with Web Sockets

1. Chat Application with Web Sockets

A simple web server

Modeling a chat room and clients on the server

Building an HTML and JavaScript chat client

Tracing code to get a look under the hood

Summary

2. Adding Authentication

2. Adding Authentication

Handlers all the way down

Making a pretty social sign-in page

Endpoints with dynamic paths

OAuth2

Tell the authentication providers about your app

Implementing external logging in

Summary

3. Three Ways to Implement Profile Pictures

3. Three Ways to Implement Profile Pictures

Avatars from the authentication server

Implementing Gravatar

Uploading an avatar picture

Combining all three implementations

Summary

4. Command-line Tools to Find Domain Names

4. Command-line Tools to Find Domain Names

Pipe design for command-line tools

Five simple programs

Composing all five programs

Summary

5. Building Distributed Systems and Working with Flexible Data

5. Building Distributed Systems and Working with Flexible Data

System design

Installing the environment

Votes from Twitter

Counting votes

Running our solution

Summary

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

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

RESTful API design

Sharing data between handlers

Wrapping handler functions

Responding

Understanding the request

A simple main function to serve our API

Handling endpoints

A web client that consumes the API

Running the solution

Summary

7. Random Recommendations Web Service

7. Random Recommendations Web Service

Project overview

Representing data in code

Generating random recommendations

Summary

8. Filesystem Backup

8. Filesystem Backup

Solution design

Backup package

The user command-line tool

The daemon backup tool

Testing our solution

Summary

A. Good Practices for a Stable Go Environment

A. Good Practices for a Stable Go Environment

Installing Go

Configuring Go

Go tools

Cleaning up, building, and running tests on save

Summary

Index

Index

Sharing data between handlers

If we want to keep our handlers as pure as the http.Handler interface from the Go standard library, while still extracting common functionality into our own methods, we need a way of sharing data between handlers. The HandlerFunc signature that follows tells us that we are only allowed to pass in an http.ResponseWriter object and an http.Request object, and nothing else:

type HandlerFunc func(http.ResponseWriter, *http.Request)

This means that we cannot create and manage database session objects in one place and pass them into our handlers, which is ideally what we want to do.

Instead, we are going to implement an in-memory map of per-request data, and provide an easy way for handlers to access it. Alongside the twittervotes and counter folders, create a new folder called api and create a new file called vars.go inside it. Add the following code to the file:

package main
import (
  "net/http"
  "sync"
)
var vars map[*http.Request]map[string]interface{}
var varsLock...

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Programming languages

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