Public: Handles all operations for resolving, cleaning and joining paths. This class includes operations for handling both web paths (request URIs) and system paths.
The main emphasis of the class is on creating clean and secure paths. Clean paths are void of duplicate parent and current directory references in the path name. Secure paths are paths which are restricted from accessing directories outside of a jail root, if specified.
Since joining two paths can result in an insecure path, this class also handles the task of joining a parent (start) and child (target) path.
This class makes no use of path utilities from the Ruby libraries. Instead, it handles all aspects of path manipulation. The main benefit of internalizing these operations is that the class is able to handle both posix and windows paths independent of the operating system on which it runs. This makes the class both deterministic and easier to test.
Examples
resolver = PathResolver.new # Web Paths resolver.web_path('images') => 'images' resolver.web_path('./images') => './images' resolver.web_path('/images') => '/images' resolver.web_path('./images/../assets/images') => './assets/images' resolver.web_path('/../images') => '/images' resolver.web_path('images', 'assets') => 'assets/images' resolver.web_path('tiger.png', '../assets/images') => '../assets/images/tiger.png' # System Paths resolver.working_dir => '/path/to/docs' resolver.system_path('images') => '/path/to/docs/images' resolver.system_path('../images') => '/path/to/images' resolver.system_path('/etc/images') => '/etc/images' resolver.system_path('images', '/etc') => '/etc/images' resolver.system_path('', '/etc/images') => '/etc/images' resolver.system_path(nil, nil, '/path/to/docs') => '/path/to/docs' resolver.system_path('..', nil, '/path/to/docs') => '/path/to/docs' resolver.system_path('../../../css', nil, '/path/to/docs') => '/path/to/docs/css' resolver.system_path('../../../css', '../../..', '/path/to/docs') => '/path/to/docs/css' resolver.system_path('..', 'C:\data\docs\assets', 'C:\data\docs') => 'C:/data/docs' resolver.system_path('..\..\css', 'C:\data\docs\assets', 'C:\data\docs') => 'C:/data/docs/css' begin resolver.system_path('../../../css', '../../..', '/path/to/docs', :recover => false) rescue SecurityError => e puts e.message end => 'path ../../../../../../css refers to location outside jail: /path/to/docs (disallowed in safe mode)' resolver.system_path('/path/to/docs/images', nil, '/path/to/docs') => '/path/to/docs/images' begin resolver.system_path('images', '/etc', '/path/to/docs') rescue SecurityError => e puts e.message end => Start path /etc is outside of jail: /path/to/docs'
Public: Construct a new instance of PathResolver, optionally specifying the file separator (to override the system default) and the working directory (to override the present working directory). The working directory will be expanded to an absolute path inside the constructor.
#file_separator - the String file separator to use for path operations
(optional, default: File::SEPARATOR)
#working_dir - the String working directory (optional, default: Dir.pwd)
# File lib/asciidoctor/path_resolver.rb, line 123 def initialize file_separator = nil, working_dir = nil @file_separator = file_separator ? file_separator : (::File::ALT_SEPARATOR || ::File::SEPARATOR) if working_dir @working_dir = (is_root? working_dir) ? working_dir : (::File.expand_path working_dir) else @working_dir = ::File.expand_path ::Dir.pwd end @_partition_path_sys = {} @_partition_path_web = {} end
Public: Expand the path by resolving any parent references (..) and cleaning self references (.).
The result will be relative if the path is relative and absolute if the path is absolute. The file separator used in the expanded path is the one specified when the class was constructed.
path - the String path to expand
returns a String path with any parent or self references resolved.
# File lib/asciidoctor/path_resolver.rb, line 196 def expand_path path path_segments, path_root, _ = partition_path path join_path path_segments, path_root end
Public: Check if the specified path is an absolute root path This operation correctly handles both posix and windows paths.
path - the String path to check
returns a Boolean indicating whether the path is an absolute root path
# File lib/asciidoctor/path_resolver.rb, line 140 def is_root? path # Unix absolute paths and UNC paths start with slash if path.start_with? SLASH true # Windows roots can begin with drive letter elsif @file_separator == BACKSLASH && WindowsRootRx =~ path true else false end end
Public: Determine if the path is a UNC (root) path
path - the String path to check
returns a Boolean indicating whether the path is a UNC path
# File lib/asciidoctor/path_resolver.rb, line 157 def is_unc? path path.start_with? DOUBLE_SLASH end
Public: Determine if the path is an absolute (root) web path
path - the String path to check
returns a Boolean indicating whether the path is an absolute (root) web path
# File lib/asciidoctor/path_resolver.rb, line 166 def is_web_root? path path.start_with? SLASH end
Public: Join the segments using the posix file separator (since Ruby knows how to work with paths specified this way, regardless of OS). Use the root, if specified, to construct an absolute path. Otherwise join the segments as a relative path.
segments - a String Array of path segments root - a String path root (optional, default: nil)
returns a String path formed by joining the segments using the posix file separator and prepending the root, if specified
# File lib/asciidoctor/path_resolver.rb, line 278 def join_path segments, root = nil if root %Q(#{root}#{segments * SLASH}) else segments * SLASH end end
Public: Partition the path into path segments and remove any empty segments or segments that are self references (.). The path is converted to a posix path before being partitioned.
path - the String path to partition #web_path - a Boolean indicating whether the path should be handled
as a web path (optional, default: false)
Returns a 3-item Array containing the Array of String path segments, the path root (e.g., '/', './', 'c:/') if the path is absolute and the posix version of the path.
# File lib/asciidoctor/path_resolver.rb, line 214 def partition_path path, web_path = false if (result = web_path ? @_partition_path_web[path] : @_partition_path_sys[path]) return result end posix_path = posixfy path root = if web_path # ex. /sample/path if is_web_root? posix_path SLASH # ex. ./sample/path elsif posix_path.start_with? DOT_SLASH DOT_SLASH # ex. sample/path else nil end else if is_root? posix_path # ex. //sample/path if is_unc? posix_path DOUBLE_SLASH # ex. /sample/path elsif posix_path.start_with? SLASH SLASH # ex. c:/sample/path else posix_path[0..(posix_path.index SLASH)] end # ex. ./sample/path elsif posix_path.start_with? DOT_SLASH DOT_SLASH # ex. sample/path else nil end end path_segments = posix_path.split SLASH # shift twice for a UNC path if root == DOUBLE_SLASH path_segments = path_segments[2..-1] # shift once for any other root elsif root path_segments.shift end # strip out all dot entries path_segments.delete DOT # QUESTION should we chomp trailing /? (we pay a small fraction) #posix_path = posix_path.chomp '/' (web_path ? @_partition_path_web : @_partition_path_sys)[path] = [path_segments, root, posix_path] end
Public: Normalize path by converting any backslashes to forward slashes
path - the String path to normalize
returns a String path with any backslashes replaced with forward slashes
# File lib/asciidoctor/path_resolver.rb, line 175 def posixfy path if path.nil_or_empty? '' elsif path.include? BACKSLASH path.tr BACKSLASH, SLASH else path end end
Public: Calculate the relative path to this absolute filename from the specified base directory
If either the filename or the base_directory are not absolute paths, no work is done.
filename - An absolute file name as a String base_directory - An absolute base directory as a String
Return the relative path String of the filename calculated from the base directory
# File lib/asciidoctor/path_resolver.rb, line 464 def relative_path filename, base_directory if (is_root? filename) && (is_root? base_directory) offset = base_directory.chomp(@file_separator).length + 1 filename[offset..-1] else filename end end
Public: Resolve a system path from the target and start paths. If a jail path is specified, enforce that the resolved directory is contained within the jail path. If a jail path is not provided, the resolved path may be any location on the system. If the resolved path is absolute, use it as is. If the resolved path is relative, resolve it relative to the #working_dir specified in the constructor.
target - the String target path start - the String start (i.e., parent) path jail - the String jail path to confine the resolved path opts - an optional Hash of options to control processing (default: {}):
* :recover is used to control whether the processor should auto-recover when an illegal path is encountered * :target_name is used in messages to refer to the path being resolved
returns a String path that joins the target path with the start path with any parent references resolved and self references removed and enforces that the resolved path be contained within the jail, if provided
# File lib/asciidoctor/path_resolver.rb, line 304 def system_path target, start, jail = nil, opts = {} recover = opts.fetch :recover, true if jail unless is_root? jail raise ::SecurityError, %Q(Jail is not an absolute path: #{jail}) end jail = posixfy jail end if target.nil_or_empty? target_segments = [] else target_segments, target_root, _ = partition_path target end if target_segments.empty? if start.nil_or_empty? return jail ? jail : @working_dir elsif is_root? start unless jail return expand_path start end else return system_path start, jail, jail end end if target_root && target_root != DOT_SLASH resolved_target = join_path target_segments, target_root # if target is absolute and a sub-directory of jail, or # a jail is not in place, let it slide if !jail || (resolved_target.start_with? jail) return resolved_target end end if start.nil_or_empty? start = jail ? jail : @working_dir elsif is_root? start start = posixfy start else start = system_path start, jail, jail end # both jail and start have been posixfied at this point if jail == start jail_segments, jail_root, _ = partition_path jail start_segments = jail_segments.dup elsif jail unless start.start_with? jail raise ::SecurityError, %Q(#{opts[:target_name] || 'Start path'} #{start} is outside of jail: #{jail} (disallowed in safe mode)) end start_segments, start_root, _ = partition_path start jail_segments, jail_root, _ = partition_path jail # Already checked for this condition #if start_root != jail_root # raise ::SecurityError, %(Jail root #{jail_root} does not match root of #{opts[:target_name] || 'start path'}: #{start_root}) #end else start_segments, start_root, _ = partition_path start jail_root = start_root end resolved_segments = start_segments.dup warned = false target_segments.each do |segment| if segment == DOT_DOT if jail if resolved_segments.length > jail_segments.length resolved_segments.pop elsif !recover raise ::SecurityError, %Q(#{opts[:target_name] || 'path'} #{target} refers to location outside jail: #{jail} (disallowed in safe mode)) elsif !warned warn %Q(asciidoctor: WARNING: #{opts[:target_name] || 'path'} has illegal reference to ancestor of jail, auto-recovering) warned = true end else resolved_segments.pop end else resolved_segments.push segment end end join_path resolved_segments, jail_root end
Public: Resolve a web path from the target and start paths. The main function of this operation is to resolve any parent references and remove any self references.
The target is assumed to be a path, not a qualified URI. That check should happen before this method is invoked.
target - the String target path start - the String start (i.e., parent) path
returns a String path that joins the target path with the start path with any parent references resolved and self references removed
# File lib/asciidoctor/path_resolver.rb, line 406 def web_path target, start = nil target = posixfy target start = posixfy start uri_prefix = nil unless start.nil_or_empty? || (is_web_root? target) target = %Q(#{start}#{SLASH}#{target}) if (target.include? ':') && UriSniffRx =~ target uri_prefix = $~[0] target = target[uri_prefix.length..-1] end end # use this logic instead if we want to normalize target if it contains a URI #unless is_web_root? target # if preserve_uri_target && (target.include? ':') && UriSniffRx =~ target # uri_prefix = $~[0] # target = target[uri_prefix.length..-1] # elsif !start.nil_or_empty? # target = %(#{start}#{SLASH}#{target}) # if (target.include? ':') && UriSniffRx =~ target # uri_prefix = $~[0] # target = target[uri_prefix.length..-1] # end # end #end target_segments, target_root, _ = partition_path target, true resolved_segments = [] target_segments.each do |segment| if segment == DOT_DOT if resolved_segments.empty? resolved_segments << segment unless target_root && target_root != DOT_SLASH elsif resolved_segments[-1] == DOT_DOT resolved_segments << segment else resolved_segments.pop end else resolved_segments << segment end end if uri_prefix %Q(#{uri_prefix}#{join_path resolved_segments, target_root}) else join_path resolved_segments, target_root end end