Book Image

Clojure Programming Cookbook

Book Image

Clojure Programming Cookbook

Overview of this book

When it comes to learning and using a new language you need an effective guide to be by your side when things get rough. For Clojure developers, these recipes have everything you need to take on everything this language offers. This book is divided into three high impact sections. The first section gives you an introduction to live programming and best practices. We show you how to interact with your connections by manipulating, transforming, and merging collections. You’ll learn how to work with macros, protocols, multi-methods, and transducers. We’ll also teach you how to work with languages such as Java, and Scala. The next section deals with intermediate-level content and enhances your Clojure skills, here we’ll teach you concurrency programming with Clojure for high performance. We will provide you with advanced best practices, tips on Clojure programming, and show you how to work with Clojure while developing applications. In the final section you will learn how to test, deploy and analyze websocket behavior when your app is deployed in the cloud. Finally, we will take you through DevOps. Developing with Clojure has never been easier with these recipes by your side!
Table of Contents (16 chapters)
Clojure Programming Cookbook
About the Authors
About the Reviewer

Making use of Clojure HTTP client

For retrieving simple HTTP requests, http-kit is a library of choice when the simple slurp function from clojure.core does not provide enough flexibility. While http-kit is both a server and a client, this recipe will only look at the client side of things.

Getting ready

Including the http-kit library into our project is now relatively straightforward. Let's add the following line to the project.clj file:

[http-kit "2.1.18"] 

How to do it...

A simple request to retrieve the weather data, as we have seen before in the parsing JSON section, is quite simply done by calling the get function of http-kit. The function returns a promise by default, meaning the call will run in the background and block when trying to get the result by calling deref or @.

Let's get set quickly with the namespace and the target URL to retrieve weather data from the openweathermap API endpoint:

(ns chapter04.somehttp1 
  (:require [org.httpkit.client :as http]))