open_loop

# File lib/open-uri.rb, line 159
  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