5. Handling Form Input | Clojure Web Development Essentials

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Table Of Contents

Clojure Web Development Essentials

By : Baldwin

4.5 (6)

Clojure Web Development Essentials

4.5 (6)

By: Baldwin

Overview of this book

This book is for anyone who's worked with Clojure and wants to use it to start developing applications for the Web. Experience or familiarity with basic Clojure syntax is a must, and exposure to Leiningen (or other similar build tools such as Maven) would be helpful.

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. Getting Started with Luminus

1. Getting Started with Luminus

Leiningen

Dependencies of the app

Luminus file structure

Summary

2. Ring and the Ring Server

2. Ring and the Ring Server

Understanding Ring in Clojure

What is the Ring Server?

Configuring and running the Ring Server

Summary

3. Logging

3. Logging

What is Timbre?

Configuring a Timbre appender

Logging with Timbre

Adding an appender

Summary

4. URL Routing and Template Rendering

4. URL Routing and Template Rendering

What is Compojure?

Creating a Compojure route

What is Selmer?

Creating your first page

Editing the home page

Serving the signup form

Creating the signup page

Summary

5. Handling Form Input

5. Handling Form Input

Handling the form POST

Validating the form POST

Summary

6. Testing in Clojure

6. Testing in Clojure

The necessity of testing

Anatomy of a test

Writing and running our first test

Writing a high-level integration test

Summary

7. Getting Started with the Database

7. Getting Started with the Database

Creating the database schema

Maintaining the database schema

Adding data to the database

Summary

8. Reading Data from the Database

8. Reading Data from the Database

Creating the catalog

Fetching albums from the database

Creating the recently added route

Rendering the results

An exercise!

Summary

9. Database Transactions

9. Database Transactions

Introduction to Database Transactions

The ACID properties

Importance of database transactions

Implementing a transaction

Extending the application requirements in brief

Summary

10. Sessions and Cookies

10. Sessions and Cookies

Sessions

Setting up sessions

Interacting with the session

Restricted routes

Cookies

Extending the application: brief requirements

Summary

11. Environment Configuration and Deployment

11. Environment Configuration and Deployment

Environ

Setting and resolving environment configurations

Adjusting the database connection

Deploying the hipstr application

Summary

A. Using Korma – a Clojure DSL for SQL

A. Using Korma – a Clojure DSL for SQL

Getting Korma

The Quick Korma Crash Course

Port the models from YeSQL to Korma

Index

Index

Handling the form POST

There are typically three things we need to do when handling form input: validate the input, show an error message if the input is invalid, and show a success message when the input is valid and accepted.

In order for us to validate the form input, we need to create a route where the form will POST. We made a number of these in the previous chapter, so we'll draw on that experience and pattern.

Let's create a new route for the same URL, /signup, but this time we'll ensure that it accepts a POST request instead of a GET request. We'll put it along with the existing /signup GET route in our hipstr.routes.home namespace:

(defroutes home-routes
  (GET   "/"        []       (home-page))
  (GET   "/about"   []       (about-page))
  (GET   "/signup"  []       (signup-page))
  (POST  "/signup"  [& form] (str "nice job"))

We now have two routes for the same URL, one that will handle the GET request, and another that will handle the POST request. You'll notice that GET doesn...

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