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Rails: Validating URLs

Here's a quick-and-dirty way to validate URLs in your model. Updated: Only allow certain schemes.
require 'uri'

class Film < ActiveRecord::Base

VALID_URI_SCHEMES = ['http', 'https']

validates_presence_of :url
validate :url_must_be_valid


def url_must_be_valid
parsed = URI.parse(url)
if !VALID_URI_SCHEMES.member?(parsed.scheme)
raise URI::InvalidURIError
rescue URI::InvalidURIError => e
errors.add(:url, 'is not a valid URL')


Matt Good said…
I've used Python's urlparse similarly, though you typically need to also check the parsed result. Lots of things will parse as URLs, but may not include stuff you'd want like a hostname, or scheme.
jjinux said…
Good point. I don't want them entering crap like file:///etc/passwd. I'll update it.
jjinux said…
Just for posterity, here are the tests I wrote:

require 'test_helper'

class MyModelTest < ActiveSupport::TestCase
# Replace this with your real tests.
test "the truth" do
assert true

test "url_must_be_valid catches bad urls" do
["*://", ""].each do |url|
my_model = = "name"
my_model.url = url
assert !my_model.valid?, url

test "url_must_be_valid accepts good urls" do
my_model = = "name"
my_model.url = ""
assert my_model.valid?, my_model.errors.full_messages
Paweł Pacana said…
This comment has been removed by the author.
Paweł Pacana said…
Well, I do this that way:

URL_FORMAT = URI::regexp(%w(http https))
validates_format_of :url, :with => URL_FORMAT
jjinux said…
Nice ;) Thanks!

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