Class: URI::Generic

Inherits:
Object
  • Object
show all
Defined in:
lib/cext/generic_find_proxy.rb

Overview

Base class for all URI classes. Implements generic URI syntax as per RFC 2396.

Instance Method Summary collapse

Instance Method Details

#find_proxy(env = ENV) ⇒ Object

returns a proxy URI. The proxy URI is obtained from environment variables such as http_proxy, ftp_proxy, no_proxy, etc. If there is no proper proxy, nil is returned.

If the optional parameter, env, is specified, it is used instead of ENV.

Note that capitalized variables (HTTP_PROXY, FTP_PROXY, NO_PROXY, etc.) are examined too.

But http_proxy and HTTP_PROXY is treated specially under CGI environment. It’s because HTTP_PROXY may be set by Proxy: header. So HTTP_PROXY is not used. http_proxy is not used too if the variable is case insensitive. CGI_HTTP_PROXY can be used instead.

Raises:

  • (BadURIError) 


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# File 'lib/cext/generic_find_proxy.rb', line 40

def find_proxy(env=ENV)
  raise BadURIError, "relative URI: #{self}" if self.relative?
  name = self.scheme.downcase + '_proxy'
  proxy_uri = nil
  if name == 'http_proxy' && env.include?('REQUEST_METHOD') # CGI?
    # HTTP_PROXY conflicts with *_proxy for proxy settings and
    # HTTP_* for header information in CGI.
    # So it should be careful to use it.
    pairs = env.reject {|k, v| /\Ahttp_proxy\z/i !~ k }
    case pairs.length
    when 0 # no proxy setting anyway.
      proxy_uri = nil
    when 1
      k, _ = pairs.shift
      if k == 'http_proxy' && env[k.upcase] == nil
        # http_proxy is safe to use because ENV is case sensitive.
        proxy_uri = env[name]
      else
        proxy_uri = nil
      end
    else # http_proxy is safe to use because ENV is case sensitive.
      proxy_uri = env.to_hash[name]
    end
    if !proxy_uri
      # Use CGI_HTTP_PROXY.  cf. libwww-perl.
      proxy_uri = env["CGI_#{name.upcase}"]
    end
  elsif name == 'http_proxy'
    unless proxy_uri = env[name]
      if proxy_uri = env[name.upcase]
        warn 'The environment variable HTTP_PROXY is discouraged.  Use http_proxy.'
      end
    end
  else
    proxy_uri = env[name] || env[name.upcase]
  end

  if proxy_uri.nil? || proxy_uri.empty?
    return nil
  end

  if self.hostname
    require 'socket'
    begin
      addr = IPSocket.getaddress(self.hostname)
      return nil if /\A127\.|\A::1\z/ =~ addr
    rescue SocketError
    end
  end

  name = 'no_proxy'
  if no_proxy = env[name] || env[name.upcase]
    no_proxy.scan(/(?!\.)([^:,\s]+)(?::(\d+))?/) {|host, port|
      if (!port || self.port == port.to_i)
        if /(\A|\.)#{Regexp.quote host}\z/i =~ self.host
          return nil
        elsif addr
          require 'ipaddr'
          return nil if
            begin
              IPAddr.new(host)
            rescue IPAddr::InvalidAddressError
              next
            end.include?(addr)
        end
      end
    }
  end
  URI.parse(proxy_uri)
end