Class: CssParser::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/css_parser/parser.rb

Overview

Parser class

All CSS is converted to UTF-8.

When calling Parser#new there are some configuaration options:

absolute_paths

Convert relative paths to absolute paths (href, src and url(''). Boolean, default is false.

import

Follow @import rules. Boolean, default is true.

io_exceptions

Throw an exception if a link can not be found. Boolean, default is true.

allow_local_network

Permit http(s) fetches against loopback / private / link-local / cloud-metadata addresses. Boolean, default is false. When false (the default), outbound HTTP requests are routed through ssrf_filter, which resolves the host and rejects unsafe IP ranges. Set to true only when the destination is known to be safe (e.g. local fixture servers in tests). Independent of allow_file_uris.

allow_file_uris

Permit file:// URIs via load_uri!. Boolean, default is false. When false (the default), a caller that passes a file:// URI to load_uri! — directly or via a CSS @import resolved against a file:// base_uri — is refused, closing the local-file-disclosure vector when the URI is influenced by user input. load_file! is unaffected: it is the explicit local-file API and takes a caller-supplied path. Independent of allow_local_network.

Constant Summary collapse

USER_AGENT = 
"Ruby CSS Parser/#{CssParser::VERSION} (https://github.com/premailer/css_parser)".freeze
RULESET_TOKENIZER_RX = 
/\s+|\\{2,}|\\?[{}\s"]|[()]|.[^\s"{}()\\]*/.freeze
STRIP_CSS_COMMENTS_RX = 
%r{/\*.*?\*/}m.freeze
STRIP_HTML_COMMENTS_RX = 
/<!--|-->/m.freeze
RE_AT_IMPORT_RULE =

Initial parsing

/@import\s*(?:url\s*)?(?:\()?(?:\s*)["']?([^'"\s)]*)["']?\)?([\w\s,^\]()]*)\)?[;\n]?/.freeze
MAX_REDIRECTS = 
3
REMOTE_ALLOWED_SCHEMES =

Schemes accepted by ‘read_remote_file`. `file://` is intentionally NOT in this list — local files are handled directly by `load_uri!` and `load_file!`. Keeping `file://` out of the remote read path closes the cross-scheme redirect (HTTP 3xx → `file://`) vector that was GHSA-9pmc-p236-855h.

%w[http https].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/css_parser/parser.rb', line 43

def initialize(options = {})
  @options = {
    absolute_paths: false,
    import: true,
    io_exceptions: true,
    rule_set_exceptions: true,
    capture_offsets: false,
    user_agent: USER_AGENT,
    allow_local_network: false,
    allow_file_uris: false
  }.merge(options)

  # array of RuleSets
  @rules = []

  @loaded_uris = []

  # unprocessed blocks of CSS
  @blocks = []
  reset!
end

Instance Attribute Details

#loaded_uris ⇒ Object (readonly)

Array of CSS files that have been loaded.



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# File 'lib/css_parser/parser.rb', line 41

def loaded_uris
  @loaded_uris
end

Instance Method Details

#add_block!(block, options = {}) ⇒ Object

Add a raw block of CSS.

In order to follow @import rules you must supply either a :base_dir or :base_uri option.

Use the :media_types option to set the media type(s) for this block. Takes an array of symbols.

Use the :only_media_types option to selectively follow @import rules. Takes an array of symbols.

Example

css = <<-EOT
  body { font-size: 10pt }
  p { margin: 0px; }
  @media screen, print {
    body { line-height: 1.2 }
  }
EOT

parser = CssParser::Parser.new
parser.add_block!(css)



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# File 'lib/css_parser/parser.rb', line 126

def add_block!(block, options = {})
  options = {base_uri: nil, base_dir: nil, charset: nil, media_types: :all, only_media_types: :all}.merge(options)
  options[:media_types] = [options[:media_types]].flatten.collect { |mt| CssParser.sanitize_media_query(mt) }
  options[:only_media_types] = [options[:only_media_types]].flatten.collect { |mt| CssParser.sanitize_media_query(mt) }

  block = cleanup_block(block, options)

  if options[:base_uri] and @options[:absolute_paths]
    block = CssParser.convert_uris(block, options[:base_uri])
  end

  # Load @imported CSS
  if @options[:import]
    block.scan(RE_AT_IMPORT_RULE).each do |import_rule|
      media_types = []
      if (media_string = import_rule[-1])
        media_string.split(',').each do |t|
          media_types << CssParser.sanitize_media_query(t) unless t.empty?
        end
      else
        media_types = [:all]
      end

      next unless options[:only_media_types].include?(:all) or media_types.empty? or media_types.intersect?(options[:only_media_types])

      import_path = import_rule[0].to_s.gsub(/['"]*/, '').strip

      import_options = {media_types: media_types}
      import_options[:capture_offsets] = true if options[:capture_offsets]

      if options[:base_uri]
        import_uri = Addressable::URI.parse(options[:base_uri].to_s) + Addressable::URI.parse(import_path)
        import_options[:base_uri] = options[:base_uri]
        load_uri!(import_uri, import_options)
      elsif options[:base_dir]
        import_options[:base_dir] = options[:base_dir]
        load_file!(import_path, import_options)
      end
    end
  end

  # Remove @import declarations
  block = ignore_pattern(block, RE_AT_IMPORT_RULE, options)

  parse_block_into_rule_sets!(block, options)
end

#add_rule!(*args, selectors: nil, block: nil, filename: nil, offset: nil, media_types: :all) ⇒ Object

Add a CSS rule by setting the selectors, declarations and media_types. Optional pass filename , offset for source reference too.

media_types can be a symbol or an array of symbols. default to :all optional fields for source location for source location filename can be a string or uri pointing to the file or url location. offset should be Range object representing the start and end byte locations where the rule was found in the file.



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# File 'lib/css_parser/parser.rb', line 181

def add_rule!(*args, selectors: nil, block: nil, filename: nil, offset: nil, media_types: :all) # rubocop:disable Metrics/ParameterLists
  if args.any?
    media_types = nil
    if selectors || block || filename || offset || media_types
      raise ArgumentError, "don't mix positional and keyword arguments arguments"
    end

    warn '[DEPRECATION] `add_rule!` with positional arguments is deprecated. ' \
         'Please use keyword arguments instead.', uplevel: 1

    case args.length
    when 2
      selectors, block = args
    when 3
      selectors, block, media_types = args
    else
      raise ArgumentError
    end
  end

  begin
    rule_set = RuleSet.new(
      selectors: selectors, block: block,
      offset: offset, filename: filename
    )

    add_rule_set!(rule_set, media_types)
  rescue ArgumentError => e
    raise e if @options[:rule_set_exceptions]
  end
end

#add_rule_set!(ruleset, media_types = :all) ⇒ Object

Add a CssParser RuleSet object.

media_types can be a symbol or an array of symbols.

Raises:

  • (ArgumentError) 


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# File 'lib/css_parser/parser.rb', line 229

def add_rule_set!(ruleset, media_types = :all)
  raise ArgumentError unless ruleset.is_a?(CssParser::RuleSet)

  media_types = [media_types] unless media_types.is_a?(Array)
  media_types = media_types.flat_map { |mt| CssParser.sanitize_media_query(mt) }

  @rules << {media_types: media_types, rules: ruleset}
end

#add_rule_with_offsets!(selectors, declarations, filename, offset, media_types = :all) ⇒ Object

Add a CSS rule by setting the selectors, declarations, filename, offset and media_types.

filename can be a string or uri pointing to the file or url location. offset should be Range object representing the start and end byte locations where the rule was found in the file. media_types can be a symbol or an array of symbols.



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# File 'lib/css_parser/parser.rb', line 218

def add_rule_with_offsets!(selectors, declarations, filename, offset, media_types = :all)
  warn '[DEPRECATION] `add_rule_with_offsets!` is deprecated. Please use `add_rule!` instead.', uplevel: 1
  add_rule!(
    selectors: selectors, block: declarations, media_types: media_types,
    filename: filename, offset: offset
  )
end

#compact! ⇒ Object

Merge declarations with the same selector.



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# File 'lib/css_parser/parser.rb', line 347

def compact! # :nodoc:
  []
end

#each_rule_set(media_types = :all) ⇒ Object

Iterate through RuleSet objects.

media_types can be a symbol or an array of symbols.



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# File 'lib/css_parser/parser.rb', line 254

def each_rule_set(media_types = :all) # :yields: rule_set, media_types
  media_types = [:all] if media_types.nil?
  media_types = [media_types].flatten.collect { |mt| CssParser.sanitize_media_query(mt) }

  @rules.each do |block|
    if media_types.include?(:all) or block[:media_types].any? { |mt| media_types.include?(mt) }
      yield(block[:rules], block[:media_types])
    end
  end
end

#each_selector(all_media_types = :all, options = {}) ⇒ Object

Iterate through CSS selectors.

media_types can be a symbol or an array of symbols. See RuleSet#each_selector for options.



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# File 'lib/css_parser/parser.rb', line 290

def each_selector(all_media_types = :all, options = {}) # :yields: selectors, declarations, specificity, media_types
  return to_enum(__method__, all_media_types, options) unless block_given?

  each_rule_set(all_media_types) do |rule_set, media_types|
    rule_set.each_selector(options) do |selectors, declarations, specificity|
      yield selectors, declarations, specificity, media_types
    end
  end
end

#find_by_selector(selector, media_types = :all) ⇒ Object Also known as: []

Get declarations by selector.

media_types are optional, and can be a symbol or an array of symbols. The default value is :all.

Examples

find_by_selector('#content')
=> 'font-size: 13px; line-height: 1.2;'

find_by_selector('#content', [:screen, :handheld])
=> 'font-size: 13px; line-height: 1.2;'

find_by_selector('#content', :print)
=> 'font-size: 11pt; line-height: 1.2;'

Returns an array of declarations.



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# File 'lib/css_parser/parser.rb', line 81

def find_by_selector(selector, media_types = :all)
  out = []
  each_selector(media_types) do |sel, dec, _spec|
    out << dec if sel.strip == selector.strip
  end
  out
end

#find_rule_sets(selectors, media_types = :all) ⇒ Object

Finds the rule sets that match the given selectors



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# File 'lib/css_parser/parser.rb', line 91

def find_rule_sets(selectors, media_types = :all)
  rule_sets = []

  selectors.each do |selector|
    selector = selector.gsub(/\s+/, ' ').strip
    each_rule_set(media_types) do |rule_set, _media_type|
      if !rule_sets.member?(rule_set) && rule_set.selectors.member?(selector)
        rule_sets << rule_set
      end
    end
  end

  rule_sets
end

#load_file!(file_name, options = {}, deprecated = nil) ⇒ Object

Load a local CSS file.



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# File 'lib/css_parser/parser.rb', line 549

def load_file!(file_name, options = {}, deprecated = nil)
  opts = {base_dir: nil, media_types: :all}

  if options.is_a? Hash
    opts.merge!(options)
  else
    warn '[DEPRECATION] `load_file!` with positional arguments is deprecated. ' \
         'Please use keyword arguments instead.', uplevel: 1
    opts[:base_dir] = options if options.is_a? String
    opts[:media_types] = deprecated if deprecated
  end

  file_name = File.expand_path(file_name, opts[:base_dir])
  return unless File.readable?(file_name)
  return unless circular_reference_check(file_name)

  src = File.read(file_name)

  opts[:filename] = file_name if opts[:capture_offsets]
  opts[:base_dir] = File.dirname(file_name)

  add_block!(src, opts)
end

#load_string!(src, options = {}, deprecated = nil) ⇒ Object

Load a local CSS string.



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# File 'lib/css_parser/parser.rb', line 574

def load_string!(src, options = {}, deprecated = nil)
  opts = {base_dir: nil, media_types: :all}

  if options.is_a? Hash
    opts.merge!(options)
  else
    warn '[DEPRECATION] `load_file!` with positional arguments is deprecated. ' \
         'Please use keyword arguments instead.', uplevel: 1
    opts[:base_dir] = options if options.is_a? String
    opts[:media_types] = deprecated if deprecated
  end

  add_block!(src, opts)
end

#load_uri!(uri, options = {}, deprecated = nil) ⇒ Object

Load a remote CSS file.

You can also pass in file://test.css

See add_block! for options.

Deprecated: originally accepted three params: ‘uri`, `base_uri` and `media_types`



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# File 'lib/css_parser/parser.rb', line 498

def load_uri!(uri, options = {}, deprecated = nil)
  uri = Addressable::URI.parse(uri) unless uri.respond_to? :scheme

  opts = {base_uri: nil, media_types: :all}

  if options.is_a? Hash
    opts.merge!(options)
  else
    warn '[DEPRECATION] `load_uri!` with positional arguments is deprecated. ' \
         'Please use keyword arguments instead.', uplevel: 1
    opts[:base_uri] = options if options.is_a? String
    opts[:media_types] = deprecated if deprecated
  end

  if uri.scheme == 'file' or uri.scheme.nil?
    uri.path = File.expand_path(uri.path)
    uri.scheme = 'file'
  end

  opts[:base_uri] = uri if opts[:base_uri].nil?

  # pass on the uri if we are capturing file offsets
  opts[:filename] = uri.to_s if opts[:capture_offsets]

  # file:// is handled here, not inside read_remote_file. The
  # remote-read path must never service file:// URIs, so a 3xx
  # `Location: file://...` redirect cannot be turned into a local
  # File.read.
  #
  # file:// via `load_uri!` is also gated by `allow_file_uris`:
  # an attacker who can influence a URI passed here (e.g. via a CSS
  # @import resolved against an attacker-controlled base_uri) could
  # otherwise turn it into arbitrary local file disclosure. Callers
  # that legitimately need to load local files should use
  # `load_file!` (the explicit local-file API).
  src = if uri.scheme == 'file'
          unless @options[:allow_file_uris]
            raise RemoteFileError, uri.to_s if @options[:io_exceptions]

            return
          end
          read_local_file(uri)
        else
          src_and_charset, = read_remote_file(uri) # skip charset
          src_and_charset
        end

  add_block!(src, opts) if src
end

#parse_block_into_rule_sets!(block, options = {}) ⇒ Object

:nodoc:



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# File 'lib/css_parser/parser.rb', line 351

def parse_block_into_rule_sets!(block, options = {}) # :nodoc:
  current_media_queries = [:all]
  if options[:media_types]
    current_media_queries = options[:media_types].flatten.collect { |mt| CssParser.sanitize_media_query(mt) }
  end

  in_declarations = 0
  block_depth = 0

  in_charset = false # @charset is ignored for now
  in_string = false
  in_at_media_rule = false
  in_media_block = false

  current_selectors = +''
  current_media_query = +''
  current_declarations = +''

  # once we are in a rule, we will use this to store where we started if we are capturing offsets
  rule_start = nil
  start_offset = nil
  end_offset = nil

  scanner = StringScanner.new(block)
  until scanner.eos?
    # save the regex offset so that we know where in the file we are
    start_offset = scanner.pos
    token = scanner.scan(RULESET_TOKENIZER_RX)
    end_offset = scanner.pos

    if token.start_with?('"') # found un-escaped double quote
      in_string = !in_string
    end

    if in_declarations > 0
      # too deep, malformed declaration block
      if in_declarations > 1
        in_declarations -= 1 if token.include?('}')
        next
      end

      if !in_string && token.include?('{')
        in_declarations += 1
        next
      end

      current_declarations << token

      if !in_string && token.include?('}')
        current_declarations.gsub!(/\}\s*$/, '')

        in_declarations -= 1
        current_declarations.strip!

        unless current_declarations.empty?
          add_rule_options = {
            selectors: current_selectors, block: current_declarations,
            media_types: current_media_queries
          }
          if options[:capture_offsets]
            add_rule_options[:filename] = options[:filename]
            add_rule_options[:offset] = rule_start..end_offset
          end
          add_rule!(**add_rule_options)
        end

        current_selectors = +''
        current_declarations = +''

        # restart our search for selectors and declarations
        rule_start = nil if options[:capture_offsets]
      end
    elsif /@media/i.match?(token)
      # found '@media', reset current media_types
      in_at_media_rule = true
      current_media_queries = []
    elsif in_at_media_rule
      if token.include?('{')
        block_depth += 1
        in_at_media_rule = false
        in_media_block = true
        current_media_queries << CssParser.sanitize_media_query(current_media_query)
        current_media_query = +''
      elsif token.include?(',')
        # new media query begins
        token.tr!(',', ' ')
        token.strip!
        current_media_query << token << ' '
        current_media_queries << CssParser.sanitize_media_query(current_media_query)
        current_media_query = +''
      else
        token.strip!
        # special-case the ( and ) tokens to remove inner-whitespace
        # (eg we'd prefer '(width: 500px)' to '( width: 500px )' )
        case token
        when '('
          current_media_query << token
        when ')'
          current_media_query.sub!(/ ?$/, token)
        else
          current_media_query << token << ' '
        end
      end
    elsif in_charset or /@charset/i.match?(token)
      # iterate until we are out of the charset declaration
      in_charset = !token.include?(';')
    elsif !in_string && token.include?('}')
      block_depth -= 1

      # reset the current media query scope
      if in_media_block
        current_media_queries = [:all]
        in_media_block = false
      end
    elsif !in_string && token.include?('{')
      current_selectors.strip!
      in_declarations += 1
    else
      # if we are in a selector, add the token to the current selectors
      current_selectors << token

      # mark this as the beginning of the selector unless we have already marked it
      rule_start = start_offset if options[:capture_offsets] && rule_start.nil? && /^[^\s]+$/.match?(token)
    end
  end

  # check for unclosed braces
  return unless in_declarations > 0

  add_rule_options = {
    selectors: current_selectors, block: current_declarations,
    media_types: current_media_queries
  }
  if options[:capture_offsets]
    add_rule_options[:filename] = options[:filename]
    add_rule_options[:offset] = rule_start..end_offset
  end
  add_rule!(**add_rule_options)
end

#remove_rule_set!(ruleset, media_types = :all) ⇒ Object

Remove a CssParser RuleSet object.

media_types can be a symbol or an array of symbols.

Raises:

  • (ArgumentError) 


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# File 'lib/css_parser/parser.rb', line 241

def remove_rule_set!(ruleset, media_types = :all)
  raise ArgumentError unless ruleset.is_a?(CssParser::RuleSet)

  media_types = [media_types].flatten.collect { |mt| CssParser.sanitize_media_query(mt) }

  @rules.reject! do |rule|
    rule[:media_types] == media_types && rule[:rules].to_s == ruleset.to_s
  end
end

#rules_by_media_query ⇒ Object

A hash of { :media_query => rule_sets }



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# File 'lib/css_parser/parser.rb', line 332

def rules_by_media_query
  rules_by_media = {}
  @rules.each do |block|
    block[:media_types].each do |mt|
      unless rules_by_media.key?(mt)
        rules_by_media[mt] = []
      end
      rules_by_media[mt] << block[:rules]
    end
  end

  rules_by_media
end

#to_h(which_media = :all) ⇒ Object

Output all CSS rules as a Hash



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# File 'lib/css_parser/parser.rb', line 266

def to_h(which_media = :all)
  out = {}
  styles_by_media_types = {}
  each_selector(which_media) do |selectors, declarations, _specificity, media_types|
    media_types.each do |media_type|
      styles_by_media_types[media_type] ||= []
      styles_by_media_types[media_type] << [selectors, declarations]
    end
  end

  styles_by_media_types.each_pair do |media_type, media_styles|
    ms = {}
    media_styles.each do |media_style|
      ms = css_node_to_h(ms, media_style[0], media_style[1])
    end
    out[media_type.to_s] = ms
  end
  out
end

#to_s(which_media = :all) ⇒ Object

Output all CSS rules as a single stylesheet.



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# File 'lib/css_parser/parser.rb', line 301

def to_s(which_media = :all)
  out = []
  styles_by_media_types = {}

  each_selector(which_media) do |selectors, declarations, _specificity, media_types|
    media_types.each do |media_type|
      styles_by_media_types[media_type] ||= []
      styles_by_media_types[media_type] << [selectors, declarations]
    end
  end

  styles_by_media_types.each_pair do |media_type, media_styles|
    media_block = (media_type != :all)
    out << "@media #{media_type} {" if media_block

    media_styles.each do |media_style|
      if media_block
        out.push("  #{media_style[0]} {\n    #{media_style[1]}\n  }")
      else
        out.push("#{media_style[0]} {\n#{media_style[1]}\n}")
      end
    end

    out << '}' if media_block
  end

  out << ''
  out.join("\n")
end