Clojure Web Development Essentials

Ryan Baldwin

• Publisher: Packt Publishing
• Year: 2015
• ISBN:
  9781784392222
• Topic: Informatique
• Subtopic: Programmation Open Source

Clojure Web Development Essentials

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Table of Contents

Clojure Web Development Essentials

Credits

About the Author

About the Reviewers

www.PacktPub.com

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Why subscribe?

Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Getting Started with Luminus

Leiningen

Using Leiningen

Generating the application

Getting help

Dependencies of the app

Luminus file structure

util.clj

session_manager.clj

layout.clj

middleware.clj

routes/home.clj

handler.clj

repl.clj

Summary

2. Ring and the Ring Server

Understanding Ring in Clojure

Request maps

Response maps

Handlers

Middleware

Adapters

What is the Ring Server?

hipstr.handler

Initialization hooks

Shutdown hooks

App routes

The application handler

hipstr.repl

Start-server

Stop-server

Get-handler

Configuring and running the Ring Server

Summary

3. Logging

What is Timbre?

What is an appender?

Configuring a Timbre appender

Timbre log levels

Appender configuration keys

Appender map

Shared appender configuration

Logging with Timbre

Adding an appender

Adding the rolling appender

Summary

4. URL Routing and Template Rendering

What is Compojure?

Creating a Compojure route

Using defroutes

Anatomy of a route

Defining the method

Defining the URL

Parameter destructuring

Destructuring the request

Destructuring unbound parameters

Constructing the response

Generating complex responses

What is Selmer?

Creating your first page

Rendering a page

Variables

Filters

Filter parameters

Tags

Template inheritance

Editing the home page

Serving the signup form

Creating the signup page

Summary

5. Handling Form Input

Handling the form POST

Validating the form POST

The noir.validation namespace

The Validateur library

Adding the Validateur dependency

Creating the user validation namespace

Validating required fields

Validating the format

Validating length of values

Validation predicates

Making reusable validators

Reporting errors to the user

Summary

6. Testing in Clojure

The necessity of testing

Anatomy of a test

Writing and running our first test

Running tests

Running tests automatically

Refactoring tests

Writing a high-level integration test

Using ring.mock.request

Summary

7. Getting Started with the Database

Creating the database schema

Maintaining the database schema

Migratus

Getting Migratus

Configuring Migratus

Creating the user table

Dropping the user table

Running the down scripts

Migrating the database

Running all migration scripts from Leiningen

Running migrations programatically

Adding migrations to the hipstr initialization

Adding data to the database

What is YeSQL?

Getting YeSQL

Adding a user to the database

Inserting a user using SQL

Inserting a user using Clojure

Bringing it all together

Adjusting the route

Encrypting the password

Summary

8. Reading Data from the Database

Creating the catalog

Creating the artists table

Seeding the artists table

Creating the albums table

Fetching albums from the database

Writing the SQL query

Creating the albums model

Refactoring the connection

Creating the recently added route

Rendering the results

An exercise!

Summary

9. Database Transactions

Introduction to Database Transactions

The ACID properties

Importance of database transactions

Implementing a transaction

Transactions in Clojure

Transactions in YeSQL

Extending the application requirements in brief

Creating the add artist/album form

Creating the form

Abstracting the form

Creating the add artist/album endpoint

Creating the Compojure route

Creating the route helper function

Validating the add artist/album form

Expanding the album model

Wrapping the whole thing in a transaction

Using a transaction outside of this scope

Summary

10. Sessions and Cookies

Sessions

Setting up sessions

Interacting with the session

Restricted routes

Restricting route access

Accessing a restricted route

Access rule as a function

Access rule as a map

Cookies

Getting a cookie's value

Setting a cookie's value

Setting the cookie as a map

Securing a cookie

Deleting a cookie

Extending the application: brief requirements

Creating the login form

Restricting the recently-added route

Restricting the route

Checking if the user is authenticated

Defining the access rule

Authenticating the user

Validating the credentials

Handling the form POST

Writing the "Remember Me" cookie

Creating the logout route

Summary

11. Environment Configuration and Deployment

Environ

Using environ

Variable translations

Setting and resolving environment configurations

Resolving environment configuration

Adjusting the database connection

Creating the profiles.clj file

Modifying the hipstr.models.connection namespace

Deploying the hipstr application

When to use an uberjar

When to use an uberwar

Deploying as a standalone

Running the application behind Nginx

Load balancing behind Nginx

Summary

A. Using Korma – a Clojure DSL for SQL

Getting Korma

The Quick Korma Crash Course

Define the database specification

Korma entities

Defining the primary key

Defining relationships between entities

Constructing SELECT queries

Constructing INSERT queries

Constructing UPDATE queries

Constructing DELETE queries

Using raw SQL

Using transactions

Port the models from YeSQL to Korma

Porting hisptr.models.connection

Porting hisptr.models.user-model

Porting hipstr.models.album-model

Index

Clojure Web Development Essentials

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