Class: LinkCheck

Inherits:
HTMLProofer::Check show all
Includes:
HTMLProofer::Utils
Defined in:
lib/html-proofer/check/links.rb

Defined Under Namespace

Classes: InternalLink, XpathFunctions

Constant Summary collapse

SRI_REL_TYPES =

Whitelist for affected elements from Subresource Integrity specification w3c.github.io/webappsec-subresource-integrity/#link-element-for-stylesheets

%(stylesheet)

Instance Attribute Summary

Attributes inherited from HTMLProofer::Check

#element, #external_urls, #html, #internal_urls, #issues, #node, #options, #path, #src

Instance Method Summary collapse

Methods included from HTMLProofer::Utils

#create_nokogiri, #pluralize, #swap

Methods inherited from HTMLProofer::Check

#add_issue, #add_to_external_urls, #add_to_internal_urls, #blank?, #create_element, #initialize, subchecks

Constructor Details

This class inherits a constructor from HTMLProofer::Check

Instance Method Details



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# File 'lib/html-proofer/check/links.rb', line 73

def check_internal_link(link, path, line, content)
  # does the local directory have a trailing slash?
  if link.unslashed_directory?(link.absolute_path)
    add_issue("internally linking to a directory #{link.absolute_path} without trailing slash", path: path, line: line, content: content)
    return false
  end

  return true unless link.hash

  # verify the target hash
  handle_hash(link, path, line, content)
end

#check_schemes(link, line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 86

def check_schemes(link, line, content)
  case link.scheme
  when 'mailto'
    handle_mailto(link, line, content)
  when 'tel'
    handle_tel(link, line, content)
  when 'http'
    return unless @options[:enforce_https]

    add_issue("#{link.href} is not an HTTPS link", line: line, content: content)
  end
end

#check_sri(line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 156

def check_sri(line, content)
  return unless SRI_REL_TYPES.include?(@link.rel)

  if !defined?(@link.integrity) && !defined?(@link.crossorigin)
    add_issue("SRI and CORS not provided in: #{@link.src}", line: line, content: content)
  elsif !defined?(@link.integrity)
    add_issue("Integrity is missing in: #{@link.src}", line: line, content: content)
  elsif !defined?(@link.crossorigin)
    add_issue("CORS not provided for external resource in: #{@link.src}", line: line, content: content)
  end
end

#external_link_check(link, line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 121

def external_link_check(link, line, content)
  if link.exists? # rubocop:disable Style/GuardClause
    target_html = create_nokogiri(link.absolute_path)
    return add_issue("linking to #{link.href}, but #{link.hash} does not exist", line: line, content: content) unless hash_exists?(target_html, link.hash)
  else
    return add_issue("trying to find hash of #{link.href}, but #{link.absolute_path} does not exist", line: line, content: content)
  end

  true
end

#find_fragments(html, fragment_ids) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 139

def find_fragments(html, fragment_ids)
  xpaths = fragment_ids.flat_map do |frag_id|
    escaped_frag_id = "'#{frag_id.split("'").join("', \"'\", '")}', ''"
    [
      "//*[case_sensitive_equals(@id, concat(#{escaped_frag_id}))]",
      "//*[case_sensitive_equals(@name, concat(#{escaped_frag_id}))]"
    ]
  end
  xpaths << XpathFunctions.new

  html.xpath(*xpaths)
end

#handle_hash(link, path, line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 111

def handle_hash(link, path, line, content)
  if link.internal? && !hash_exists?(link.html, link.hash) # rubocop:disable Style/GuardClause
    return add_issue("linking to internal hash ##{link.hash} that does not exist", path: path, line: line, content: content)
  elsif link.external?
    return external_link_check(link, line, content)
  end

  true
end

#handle_mailto(link, line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 99

def handle_mailto(link, line, content)
  if link.path.empty?
    add_issue("#{link.href} contains no email address", line: line, content: content)
  elsif !link.path.include?('@')
    add_issue("#{link.href} contains an invalid email address", line: line, content: content)
  end
end

#handle_tel(link, line, content) ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 107

def handle_tel(link, line, content)
  add_issue("#{link.href} contains no phone number", line: line, content: content) if link.path.empty?
end

#hash_exists?(html, href_hash) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/html-proofer/check/links.rb', line 132

def hash_exists?(html, href_hash)
  decoded_href_hash = Addressable::URI.unescape(href_hash)
  fragment_ids = [href_hash, decoded_href_hash]
  # https://www.w3.org/TR/html5/single-page.html#scroll-to-fragid
  fragment_ids.include?('top') || !find_fragments(html, fragment_ids).empty?
end

#missing_href? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/html-proofer/check/links.rb', line 6

def missing_href?
  return blank?(@link.src) if @node.name == 'source'

  blank?(@link.href) && blank?(@link.name) && blank?(@link.id)
end

#placeholder? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/html-proofer/check/links.rb', line 12

def placeholder?
  (!blank?(@link.id) || !blank?(@link.name)) && @link.href.nil?
end

#run ⇒ Object 



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# File 'lib/html-proofer/check/links.rb', line 16

def run
  @html.css('a, link, source').each do |node|
    @link = create_element(node)
    line = node.line
    content = node.to_s

    next if @link.ignore?

    next if placeholder?
    next if @link.allow_hash_href? && @link.href == '#'

    # is it even a valid URL?
    unless @link.valid?
      add_issue("#{@link.href} is an invalid URL", line: line, content: content)
      next
    end

    check_schemes(@link, line, content)

    # is there even an href?
    if missing_href?
      next if @link.allow_missing_href?
      # HTML5 allows dropping the href: http://git.io/vBX0z
      next if @html.internal_subset.nil? || (@html.internal_subset.name == 'html' && @html.internal_subset.external_id.nil?)

      add_issue('anchor has no href attribute', line: line, content: content)
      next
    end

    # intentionally here because we still want valid? & missing_href? to execute
    next if @link.non_http_remote?

    if !@link.href&.start_with?('#') && !@link.internal? && @link.remote?
      check_sri(line, content) if @link.check_sri? && node.name == 'link'
      # we need to skip these for now; although the domain main be valid,
      # curl/Typheous inaccurately return 404s for some links. cc https://git.io/vyCFx
      next if @link.respond_to?(:rel) && @link.rel == 'dns-prefetch'

      unless @link.path?
        add_issue("#{@link.href} is an invalid URL", line: line, content: content)
        next
      end

      add_to_external_urls(@link.href || @link.src)
      next
    elsif @link.internal?
      if @link.exists? || @link.hash
        add_to_internal_urls(@link.href, InternalLink.new(@link, @path, line, content))
      else
        add_issue("internally linking to #{@link.href}, which does not exist", line: line, content: content)
      end
    end
  end

  external_urls
end