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Validating Author Data in an Online Bookstore

In this third part of a four-part article series on building an online bookstore application with Ruby on Rails, you'll learn how to actually create authors in the system, validate data, and more. This article is excerpted from chapter two of the book Practical Rails Projects, written by Eldon Alameda (Apress; ISBN: 1590597818).

Author Info:
By: Apress Publishing
Rating: 5 stars5 stars5 stars5 stars5 stars / 1
May 13, 2010
  1. · Validating Author Data in an Online Bookstore
  2. · Creating the Author
  3. · Validating Data
  4. · Listing Authors

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Validating Author Data in an Online Bookstore - Validating Data
(Page 3 of 4 )

ActiveRecord validations are a way to enforce restrictions upon editing the business model objects of your application. For example, you might want to make sure that an e-mail address is valid or that the balance of an account can never be less than zero.

In our case, we just want to make sure that every time someone tries to add or update anAuthorobject, that object has both the first and the last name specified. This can be accomplished with thevalidates_presence_ofmethod, so letís openapp/models/author.rband add a line of code there to make the validations work:

class Author < ActiveRecord::Base
validates_presence_of :first_name, :last_name

  def name
    "#{first_name} #{last_name}"

We will meet a lot more validations during the course of this book, but for now, letís just settle with this and try to run our tests again.

$ ruby test/functional/admin/author_controller_test.rb

Loaded suite test/functional/admin/author_controller_test Started
Finished in 0.171436 seconds.

2 tests, 12 assertions, 0 failures, 0 errors

The results look good. We can now point our browser tohttp://localhost:3000/admin/author/newand try to create a new author. Leaving the last name blank, weíre greeted with the response shown in Figure 2-2 when the form is submitted.

Figure 2-2.  Failing creation of a new author

Seems that our validations are working, and as the tests agree, we move on to implement editing of existing authors.

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