open-uri.rb

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#= open-uri.rb
#
#open-uri.rb is easy-to-use wrapper for net/http, net/https and net/ftp.
#
#== Example
#
#It is possible to open http/https/ftp URL as usual a file:
#
#  open("http://www.ruby-lang.org/") {|f|
#    f.each_line {|line| p line}
#  }
#
#The opened file has several methods for meta information as follows since
#it is extended by OpenURI::Meta.
#
#  open("http://www.ruby-lang.org/en") {|f|
#    f.each_line {|line| p line}
#    p f.base_uri         # <URI::HTTP:0x40e6ef2 URL:http://www.ruby-lang.org/en/>
#    p f.content_type     # "text/html"
#    p f.charset          # "iso-8859-1"
#    p f.content_encoding # []
#    p f.last_modified    # Thu Dec 05 02:45:02 UTC 2002
#  }
#
#Additional header fields can be specified by an optional hash argument.
#
#  open("http://www.ruby-lang.org/en/",
#    "User-Agent" => "Ruby/#{RUBY_VERSION}",
#    "From" => "[e-mail]",
#    "Referer" => "http://www.ruby-lang.org/") {|f|
#    ...
#  }
#
#The environment variables such as http_proxy, https_proxy and ftp_proxy
#are in effect by default.  :proxy => nil disables proxy.
#
#  open("http://www.ruby-lang.org/en/raa.html",
#    :proxy => nil) {|f|
#    ...
#  }
#
#URI objects can be opened in similar way.
#
#  uri = URI.parse("http://www.ruby-lang.org/en/")
#  uri.open {|f|
#    ...
#  }
#
#URI objects can be read directly.
#The returned string is also extended by OpenURI::Meta.
#
#  str = uri.read
#  p str.base_uri
#
#Author:: Tanaka Akira <[e-mail]>
#--
# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
# All rights reserved.
# See LICENSE.txt for permissions.
#++


require 'uri'
require 'stringio'
require 'time'

module Kernel
  private
  alias open_uri_original_open open # :nodoc:

  # makes possible to open various resources including URIs.
  # If the first argument respond to `open' method,
  # the method is called with the rest arguments.
  #
  # If the first argument is a string which begins with xxx://,
  # it is parsed by URI.parse.  If the parsed object respond to `open' method,
  # the method is called with the rest arguments.
  #
  # Otherwise original open is called.
  #
  # Since open-uri.rb provides URI::HTTP#open, URI::HTTPS#open and
  # URI::FTP#open,
  # Kernel[#.]open can accepts such URIs and strings which begins with
  # http://, https:// and ftp://.
  # In these case, the opened file object is extended by OpenURI::Meta.
  def open(name, *rest, &block) # :doc:
    if name.respond_to?(:open)
      name.open(*rest, &block)
    elsif name.respond_to?(:to_str) &&
          %r{\A[A-Za-z][A-Za-z0-9+\-\.]*://} =~ name &&
          (uri = URI.parse(name)).respond_to?(:open)
      uri.open(*rest, &block)
    else
      open_uri_original_open(name, *rest, &block)
    end
  end
  module_function :open
end

module OpenURI
  Options = {
    :proxy => true,
    :proxy_http_basic_authentication => true,
    :progress_proc => true,
    :content_length_proc => true,
    :http_basic_authentication => true,
    :read_timeout => true,
  }

  def OpenURI.check_options(options) # :nodoc:
    options.each {|k, v|
      next unless Symbol === k
      unless Options.include? k
        raise ArgumentError, "unrecognized option: #{k}"
      end
    }
  end

  def OpenURI.scan_open_optional_arguments(*rest) # :nodoc:
    if !rest.empty? && (String === rest.first || Integer === rest.first)
      mode = rest.shift
      if !rest.empty? && Integer === rest.first
        perm = rest.shift
      end
    end
    return mode, perm, rest
  end

  def OpenURI.open_uri(name, *rest) # :nodoc:
    uri = URI::Generic === name ? name : URI.parse(name)
    mode, perm, rest = OpenURI.scan_open_optional_arguments(*rest)
    options = rest.shift if !rest.empty? && Hash === rest.first
    raise ArgumentError.new("extra arguments") if !rest.empty?
    options ||= {}
    OpenURI.check_options(options)

    unless mode == nil ||
           mode == 'r' || mode == 'rb' ||
           mode == File::RDONLY
      raise ArgumentError.new("invalid access mode #{mode} (#{uri.class} resource is read only.)")
    end

    io = open_loop(uri, options)
    if block_given?
      begin
        yield io
      ensure
        io.close
      end
    else
      io
    end
  end

  def OpenURI.open_loop(uri, options) # :nodoc:
    proxy_opts = []
    proxy_opts << :proxy_http_basic_authentication if options.include? :proxy_http_basic_authentication
    proxy_opts << :proxy if options.include? :proxy
    proxy_opts.compact!
    if 1 < proxy_opts.length
      raise ArgumentError, "multiple proxy options specified"
    end
    case proxy_opts.first
    when :proxy_http_basic_authentication
      opt_proxy, proxy_user, proxy_pass = options.fetch(:proxy_http_basic_authentication)
      proxy_user = proxy_user.to_str
      proxy_pass = proxy_pass.to_str
      if opt_proxy == true
        raise ArgumentError.new("Invalid authenticated proxy option: #{options[:proxy_http_basic_authentication].inspect}")
      end
    when :proxy
      opt_proxy = options.fetch(:proxy)
      proxy_user = nil
      proxy_pass = nil
    when nil
      opt_proxy = true
      proxy_user = nil
      proxy_pass = nil
    end
    case opt_proxy
    when true
      find_proxy = lambda {|u| pxy = u.find_proxy; pxy ? [pxy, nil, nil] : nil}
    when nil, false
      find_proxy = lambda {|u| nil}
    when String
      opt_proxy = URI.parse(opt_proxy)
      find_proxy = lambda {|u| [opt_proxy, proxy_user, proxy_pass]}
    when URI::Generic
      find_proxy = lambda {|u| [opt_proxy, proxy_user, proxy_pass]}
    else
      raise ArgumentError.new("Invalid proxy option: #{opt_proxy}")
    end

    uri_set = {}
    buf = nil
    while true
      redirect = catch(:open_uri_redirect) {
        buf = Buffer.new
        uri.buffer_open(buf, find_proxy.call(uri), options)
        nil
      }
      if redirect
        if redirect.relative?
          # Although it violates RFC2616, Location: field may have relative
          # URI.  It is converted to absolute URI using uri as a base URI.
          redirect = uri + redirect
        end
        unless OpenURI.redirectable?(uri, redirect)
          raise "redirection forbidden: #{uri} -> #{redirect}"
        end
        if options.include? :http_basic_authentication
          # send authentication only for the URI directly specified.
          options = options.dup
          options.delete :http_basic_authentication
        end
        uri = redirect
        raise "HTTP redirection loop: #{uri}" if uri_set.include? uri.to_s
        uri_set[uri.to_s] = true
      else
        break
      end
    end
    io = buf.io
    io.base_uri = uri
    io
  end

  def OpenURI.redirectable?(uri1, uri2) # :nodoc:
    # This test is intended to forbid a redirection from http://... to
    # file:///etc/passwd.
    # However this is ad hoc.  It should be extensible/configurable.
    uri1.scheme.downcase == uri2.scheme.downcase ||
    (/\A(?:http|ftp)\z/i =~ uri1.scheme && /\A(?:http|ftp)\z/i =~ uri2.scheme)
  end

  def OpenURI.open_http(buf, target, proxy, options) # :nodoc:
    if proxy
      proxy_uri, proxy_user, proxy_pass = proxy
      raise "Non-HTTP proxy URI: #{proxy_uri}" if proxy_uri.class != URI::HTTP
    end

    if target.userinfo && "1.9.0" <= RUBY_VERSION
      # don't raise for 1.8 because compatibility.
      raise ArgumentError, "userinfo not supported.  [RFC3986]"
    end

    header = {}
    options.each {|k, v| header[k] = v if String === k }

    require 'net/http'
    klass = Net::HTTP
    if URI::HTTP === target
      # HTTP or HTTPS
      if proxy
        if proxy_user && proxy_pass
          klass = Net::HTTP::Proxy(proxy_uri.host, proxy_uri.port, proxy_user, proxy_pass)
        else
          klass = Net::HTTP::Proxy(proxy_uri.host, proxy_uri.port)
        end
      end
      target_host = target.host
      target_port = target.port
      request_uri = target.request_uri
    else
      # FTP over HTTP proxy
      target_host = proxy_uri.host
      target_port = proxy_uri.port
      request_uri = target.to_s
      if proxy_user && proxy_pass
        header["Proxy-Authorization"] = 'Basic ' + ["#{proxy_user}:#{proxy_pass}"].pack('m').delete("\r\n")
      end
    end

    http = klass.new(target_host, target_port)
    if target.class == URI::HTTPS
      require 'net/https'
      http.use_ssl = true
      http.verify_mode = OpenSSL::SSL::VERIFY_PEER
      store = OpenSSL::X509::Store.new
      store.set_default_paths
      http.cert_store = store
    end
    if options.include? :read_timeout
      http.read_timeout = options[:read_timeout]
    end

    resp = nil
    http.start {
      if target.class == URI::HTTPS
        # xxx: information hiding violation
        sock = http.instance_variable_get(:@socket)
        if sock.respond_to?(:io)
          sock = sock.io # 1.9
        else
          sock = sock.instance_variable_get(:@socket) # 1.8
        end
        sock.post_connection_check(target_host)
      end
      req = Net::HTTP::Get.new(request_uri, header)
      if options.include? :http_basic_authentication
        user, pass = options[:http_basic_authentication]
        req.basic_auth user, pass
      end
      http.request(req) {|response|
        resp = response
        if options[:content_length_proc] && Net::HTTPSuccess === resp
          if resp.key?('Content-Length')
            options[:content_length_proc].call(resp['Content-Length'].to_i)
          else
            options[:content_length_proc].call(nil)
          end
        end
        resp.read_body {|str|
          buf << str
          if options[:progress_proc] && Net::HTTPSuccess === resp
            options[:progress_proc].call(buf.size)
          end
        }
      }
    }
    io = buf.io
    io.rewind
    io.status = [resp.code, resp.message]
    resp.each {|name,value| buf.io.meta_add_field name, value }
    case resp
    when Net::HTTPSuccess
    when Net::HTTPMovedPermanently, # 301
         Net::HTTPFound, # 302
         Net::HTTPSeeOther, # 303
         Net::HTTPTemporaryRedirect # 307
      throw :open_uri_redirect, URI.parse(resp['location'])
    else
      raise OpenURI::HTTPError.new(io.status.join(' '), io)
    end
  end

  class HTTPError < StandardError
    def initialize(message, io)
      super(message)
      @io = io
    end
    attr_reader :io
  end

  class Buffer # :nodoc:
    def initialize
      @io = StringIO.new
      @size = 0
    end
    attr_reader :size

    StringMax = 10240
    def <<(str)
      @io << str
      @size += str.length
      if StringIO === @io && StringMax < @size
        require 'tempfile'
        io = Tempfile.new('open-uri')
        io.binmode
        Meta.init io, @io if @io.respond_to? :meta
        io << @io.string
        @io = io
      end
    end

    def io
      Meta.init @io unless @io.respond_to? :meta
      @io
    end
  end

  # Mixin for holding meta-information.
  module Meta
    def Meta.init(obj, src=nil) # :nodoc:
      obj.extend Meta
      obj.instance_eval {
        @base_uri = nil
        @meta = {}
      }