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

module Kernel
  private
  alias open_uri_original_open open # :nodoc:
  class << self
    alias open_uri_original_open open # :nodoc:
  end

  # Allows the opening of various resources including URIs.
  #
  # If the first argument responds to the 'open' method, 'open' is called on
  # it with the rest of the arguments.
  #
  # If the first argument is a string that begins with xxx://, it is parsed by
  # URI.parse.  If the parsed object responds to the 'open' method,
  # 'open' is called on it with the rest of the arguments.
  #
  # Otherwise, the original Kernel#open is called.
  #
  # Since open-uri.rb provides URI::HTTP#open, URI::HTTPS#open and
  # URI::FTP#open, Kernel[#.]open can accept URIs and strings that begin with
  # http://, https:// and ftp://.  In these cases, 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

# OpenURI is an easy-to-use wrapper for net/http, net/https and net/ftp.
#
#== Example
#
# It is possible to open an http, https or ftp URL as though it were a file:
#
#   open("http://www.ruby-lang.org/") {|f|
#     f.each_line {|line| p line}
#   }
#
# The opened file has several getter methods for its 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" => "foo@bar.invalid",
#     "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/", :proxy => nil) {|f|
#     # ...
#   }
#
# URI objects can be opened in a 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 <akr@m17n.org>

module OpenURI
  Options = {
    :proxy => true,
    :proxy_http_basic_authentication => true,
    :progress_proc => true,
    :content_length_proc => true,
    :http_basic_authentication => true,
    :read_timeout => true,
    :ssl_ca_cert => nil,
    :ssl_verify_mode => nil,
    :ftp_active_mode => false,
    :redirect => 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, _, 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)

    if /\Arb?(?:\Z|:([^:]+))/ =~ mode
      encoding, = $1,Encoding.find($1) if $1
      mode = nil
    end

    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)
    io.set_encoding(encoding) if encoding
    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
        if !options.fetch(:redirect, true)
          raise HTTPRedirect.new(buf.io.status.join(' '), buf.io, 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, file:///dev/zero, etc.  CVE-2011-1521
    # https to http redirect is also forbidden intentionally.
    # It avoids sending secure cookie or referer by non-secure HTTP protocol.
    # (RFC 2109 4.3.1, RFC 2965 3.3, RFC 2616 15.1.3)
    # 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.hostname, proxy_uri.port, proxy_user, proxy_pass)
        else
          klass = Net::HTTP::Proxy(proxy_uri.hostname, proxy_uri.port)
        end
      end
      target_host = target.hostname
      target_port = target.port
      request_uri = target.request_uri
    else
      # FTP over HTTP proxy
      target_host = proxy_uri.hostname
      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 = options[:ssl_verify_mode] || OpenSSL::SSL::VERIFY_PEER
      store = OpenSSL::X509::Store.new
      if options[:ssl_ca_cert]
        if File.directory? options[:ssl_ca_cert]
          store.add_path options[:ssl_ca_cert]
        else
          store.add_file options[:ssl_ca_cert]
        end
      else
        store.set_default_paths
      end
      http.cert_store = store
    end
    if options.include? :read_timeout
      http.read_timeout = options[:read_timeout]
    end

    resp = nil
    http.start {
      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
      begin
        loc_uri = URI.parse(resp['location'])
      rescue URI::InvalidURIError
        raise OpenURI::HTTPError.new(io.status.join(' ') + ' (Invalid Location URI)', io)
      end
      throw :open_uri_redirect, loc_uri
    else