urbanadventurer/WhatWeb · error

You must specify the available url of the website

Error message

You must specify the available url of the website

What it means

Version#initialize requires a non-nil URL of the website hosting version-specific files. When the `url` argument is nil (or omitted), the constructor raises this error. Without a URL the Version object cannot fetch the files whose checksums are compared to fingerprint the product version.

Solutions

1. Pass a valid website URL as the third argument to Version.new
2. Ensure the target URL string is non-nil before constructing the Version (parse the target first and fall back to a known base URL)
3. Check argument order: initialize(name_product, versions, url)
4. Build the Version only after a target URL has been successfully resolved

Example fix

// before
v = Version.new('Apache', ['2.4.57'], nil)
// after
v = Version.new('Apache', ['2.4.57'], 'http://example.com/')

raise ArgumentError, 'url is required' if url.nil? || url.to_s.strip.empty?
v = Version.new('Apache', ['2.4.57'], url)

def valid_url?(u)
  u.is_a?(String) && !u.strip.empty?
end

When it happens

Trigger: Calling Version.new(name, versions, nil), Version.new(name, versions) with the third positional argument omitted, or passing a nil variable (e.g. a target whose host extraction failed) as the url argument.

Common situations: Scripted WhatWeb usage where the matched target URL was not propagated into the Version constructor; refactors that changed from keyword-style to positional arguments dropping the url; nil propagation from failed target parsing upstream.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• You must specify the available versions of the product
• No target
• Error parsing target IP range: #
• Unable to parse invalid target. No hostname.
• You must specify the name of the product

AI-assisted analysis of urbanadventurer/WhatWeb@d279d93042 (2026-09-15). Data as JSON: /api/errors/ac78e9591a90846e. Report an issue: GitHub.

Appendix: source

Thrown at lib/version_class.rb:22

#
# WhatWeb is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# at your option) any later version.
#
# WhatWeb is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with WhatWeb.  If not, see <http://www.gnu.org/licenses/>.

class Version
  def initialize(name_product = nil, versions = nil, url = nil)
    raise 'You must specify the name of the product' if name_product.nil?
    raise 'You must specify the available versions of the product' if versions.nil?
    raise 'You must specify the available url of the website' if url.nil?

    @name = name_product
    @versions = versions
    @files = Hash['filenames' => [], 'files' => [], 'md5' => []]
    @url = url
    @got_best_versions = false
    @best_versions = []

    versions.each do |version|
      version[1].each do |file|
        next if @files['filenames'].include? file[0]
        @files['filenames'].push(file[0])
        @files['files'].push(URI.join(@url.to_s, file[0]).to_s)
        _status, url, _ip, body, _headers = open_target(@files['files'].last)
        @files['md5'].push(Digest::MD5.hexdigest(body))
      end
    end
  end

View on GitHub (pinned to d279d93042)