ruby 15 lines · 6 steps

Normalizing user input in Rails models

How a Rails model cleans up attributes before validating them.

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Rails Intermediate normalization validation data integrity activerecord lambdas
1class User < ApplicationRecord
2 has_secure_password
3 
4 normalizes :email, with: ->(email) { email.strip.downcase }
5 normalizes :phone, with: ->(phone) { phone.gsub(/\D/, "") }
6 normalizes :username, with: ->(username) { username.strip.gsub(/\s+/, "_").downcase }
7 normalizes :website, with: ->(url) { url.blank? ? url : url.sub(%r{\Ahttps?://}i, "") }
8 
9 validates :email, presence: true, uniqueness: true,
10 format: { with: URI::MailTo::EMAIL_REGEXP }
11 validates :phone, length: { is: 10 }, allow_blank: true
12 validates :username, presence: true, uniqueness: true,
13 length: { in: 3..30 },
14 format: { with: /\A[a-z0-9_]+\z/ }
15end
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STEP 01

Walkthrough

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Three takeaways
  1. 1Normalizing attributes before validation means your rules check clean data, not raw input.
  2. 2Pairing normalization with a matching validation prevents subtle mismatches like case-sensitive uniqueness bugs.
  3. 3Declarative model macros keep data-cleaning logic centralized instead of scattered across controllers.

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