Module: BrazilianUtils::EmailUtils

Defined in:

lib/brazilian-utils/email-utils.rb

Constant Summary

EMAIL_PATTERN =

Email validation pattern based on RFC 5322/RFC 1035.

This is stricter than brutils/python's reference regex (^(?![.])[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$), which lets through addresses with a leading/trailing/doubled dot in the local part, or a domain label starting/ending with a hyphen. Each dot-joined segment is validated on its own:

• Local part: one or more non-empty segments (letters, digits, ._%+-) joined by single dots - no leading/trailing/consecutive dot
• Domain labels: alphanumeric, may contain internal hyphens, but must not start or end with one (RFC 1035 "preferred name syntax")
• TLD: at least 2 letters, no digits or hyphens

%r{
  \A
  [a-zA-Z0-9_%+-]+ (?: \. [a-zA-Z0-9_%+-]+ )*                # local part
  @
  (?: [a-zA-Z0-9] (?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])? \. )+   # domain labels
  [a-zA-Z]{2,63}                                             # TLD
  \z
}x.freeze

Class Method Summary

• .is_valid(email) ⇒ Boolean (also: valid?)

  Checks if a string corresponds to a valid email address.

Class Method Details

.is_valid(email) ⇒ Boolean Also known as: valid?

Note:

The validation rules generally follow RFC 5322 specifications:

• Local part cannot start with a dot
• Local part can contain: letters, numbers, dots, underscores, percent, plus, minus
• Must have @ symbol
• Domain can contain: letters, numbers, dots, hyphens
• Must have at least one dot in domain
• TLD must be at least 2 characters and only letters

Checks if a string corresponds to a valid email address.

This function validates email addresses following the specifications defined by RFC 5322, which is the widely accepted standard for email address formats.

Examples:

Valid emails

is_valid("brutils@brutils.com")       #=> true
is_valid("user.name@example.com")     #=> true
is_valid("user+tag@example.co.uk")    #=> true
is_valid("user_123@test-domain.com")  #=> true

Invalid emails

is_valid("invalid-email@brutils")     #=> false (no TLD)
is_valid(".user@example.com")         #=> false (starts with dot)
is_valid("user@")                     #=> false (no domain)
is_valid("@example.com")              #=> false (no local part)
is_valid("user name@example.com")     #=> false (space not allowed)
is_valid(nil)                         #=> false (not a string)

Parameters:

• email (String) —

  The input string to be checked

Returns:

• (Boolean) —

  Returns true if email is a valid email address, false otherwise

# File 'lib/brazilian-utils/email-utils.rb', line 54

def self.is_valid(email)
  return false unless email.is_a?(String)

  EMAIL_PATTERN.match?(email)
end