FileTest implements file test operations similar to those used in File::Stat. It exists as a standalone module, and its methods are also insinuated into the File class. (Note that this is not done by inclusion: the interpreter cheats).

Include the English library file in a Ruby script, and you can reference the global variables such as VAR{$_} using less cryptic names, listed in the following table.% vref{tab:english}.

Without ‘English’:

$\ = ' -- '
"waterbuffalo" =~ /buff/
print $', $$, "\n"

With English:

require "English"

$OUTPUT_FIELD_SEPARATOR = ' -- '
"waterbuffalo" =~ /buff/
print $POSTMATCH, $PID, "\n"

Below is a full list of descriptive aliases and their associated global variable:

$ERROR_INFO

$!

$ERROR_POSITION

$@

$FS

$;

$FIELD_SEPARATOR

$;

$OFS

$,

$OUTPUT_FIELD_SEPARATOR

$,

$RS

$/

$INPUT_RECORD_SEPARATOR

$/

$ORS

$\

$OUTPUT_RECORD_SEPARATOR

$\

$INPUT_LINE_NUMBER

$.

$NR

$.

$LAST_READ_LINE

$_

$DEFAULT_OUTPUT

$>

$DEFAULT_INPUT

$<

$PID

$$

$PROCESS_ID

$$

$CHILD_STATUS

$?

$LAST_MATCH_INFO

$~

$IGNORECASE

$=

$ARGV

$*

$MATCH

$&

$PREMATCH

$‘

$POSTMATCH

$‘

$LAST_PAREN_MATCH

$+

The Find module supports the top-down traversal of a set of file paths.

For example, to total the size of all files under your home directory, ignoring anything in a “dot” directory (e.g. $HOME/.ssh):

require 'find'

total_size = 0

Find.find(ENV["HOME"]) do |path|
  if FileTest.directory?(path)
    if File.basename(path)[0] == ?.
      Find.prune       # Don't look any further into this directory.
    else
      next
    end
  else
    total_size += FileTest.size(path)
  end
end

In concurrent programming, a monitor is an object or module intended to be used safely by more than one thread. The defining characteristic of a monitor is that its methods are executed with mutual exclusion. That is, at each point in time, at most one thread may be executing any of its methods. This mutual exclusion greatly simplifies reasoning about the implementation of monitors compared to reasoning about parallel code that updates a data structure.

You can read more about the general principles on the Wikipedia page for Monitors

Examples

Simple object.extend

require 'monitor.rb'

buf = []
buf.extend(MonitorMixin)
empty_cond = buf.new_cond

# consumer
Thread.start do
  loop do
    buf.synchronize do
      empty_cond.wait_while { buf.empty? }
      print buf.shift
    end
  end
end

# producer
while line = ARGF.gets
  buf.synchronize do
    buf.push(line)
    empty_cond.signal
  end
end

The consumer thread waits for the producer thread to push a line to buf while buf.empty?. The producer thread (main thread) reads a line from ARGF and pushes it into buf then calls empty_cond.signal to notify the consumer thread of new data.

Simple Class include

require 'monitor'

class SynchronizedArray < Array

  include MonitorMixin

  def initialize(*args)
    super(*args)
  end

  alias :old_shift :shift
  alias :old_unshift :unshift

  def shift(n=1)
    self.synchronize do
      self.old_shift(n)
    end
  end

  def unshift(item)
    self.synchronize do
      self.old_unshift(item)
    end
  end

  # other methods ...
end

SynchronizedArray implements an Array with synchronized access to items. This Class is implemented as subclass of Array which includes the MonitorMixin module.

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. Here we disable proxy:

open("http://www.ruby-lang.org/en/", :proxy => nil) {|f|
  # ...
}

See OpenURI::OpenRead.open and Kernel#open for more on available options.

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>

URI is a module providing classes to handle Uniform Resource Identifiers (RFC2396)

Features

• Uniform handling of handling URIs

• Flexibility to introduce custom URI schemes

• Flexibility to have an alternate URI::Parser (or just different patterns and regexp’s)

Basic example

require 'uri'

uri = URI("http://foo.com/posts?id=30&limit=5#time=1305298413")
#=> #<URI::HTTP:0x00000000b14880
      URL:http://foo.com/posts?id=30&limit=5#time=1305298413>
uri.scheme
#=> "http"
uri.host
#=> "foo.com"
uri.path
#=> "/posts"
uri.query
#=> "id=30&limit=5"
uri.fragment
#=> "time=1305298413"

uri.to_s
#=> "http://foo.com/posts?id=30&limit=5#time=1305298413"

Adding custom URIs

module URI
  class RSYNC < Generic
    DEFAULT_PORT = 873
  end
  @@schemes['RSYNC'] = RSYNC
end
#=> URI::RSYNC

URI.scheme_list
#=> {"FTP"=>URI::FTP, "HTTP"=>URI::HTTP, "HTTPS"=>URI::HTTPS,
     "LDAP"=>URI::LDAP, "LDAPS"=>URI::LDAPS, "MAILTO"=>URI::MailTo,
     "RSYNC"=>URI::RSYNC}

uri = URI("rsync://rsync.foo.com")
#=> #<URI::RSYNC:0x00000000f648c8 URL:rsync://rsync.foo.com>

RFC References

A good place to view an RFC spec is www.ietf.org/rfc.html

Here is a list of all related RFC’s.

• RFC822

• RFC1738

• RFC2255

• RFC2368

• RFC2373

• RFC2396

• RFC2732

• RFC3986

Class tree

• URI::Generic (in uri/generic.rb)

  • URI::FTP - (in uri/ftp.rb)

  • URI::HTTP - (in uri/http.rb)

    • URI::HTTPS - (in uri/https.rb)

  • URI::LDAP - (in uri/ldap.rb)

    • URI::LDAPS - (in uri/ldaps.rb)

  • URI::MailTo - (in uri/mailto.rb)

• URI::Parser - (in uri/common.rb)

• URI::REGEXP - (in uri/common.rb)

  • URI::REGEXP::PATTERN - (in uri/common.rb)

• URI::Util - (in uri/common.rb)

• URI::Escape - (in uri/common.rb)

• URI::Error - (in uri/common.rb)

  • URI::InvalidURIError - (in uri/common.rb)

  • URI::InvalidComponentError - (in uri/common.rb)

  • URI::BadURIError - (in uri/common.rb)

Copyright Info

Author

Akira Yamada <akira@ruby-lang.org>

Documentation

Akira Yamada <akira@ruby-lang.org> Dmitry V. Sabanin <sdmitry@lrn.ru> Vincent Batts <vbatts@hashbangbash.com>

License

Copyright © 2001 akira yamada <akira@ruby-lang.org> You can redistribute it and/or modify it under the same term as Ruby.

Revision

$Id: uri.rb 53141 2015-12-16 05:07:31Z naruse $

WEB server toolkit.

WEBrick is an HTTP server toolkit that can be configured as an HTTPS server, a proxy server, and a virtual-host server. WEBrick features complete logging of both server operations and HTTP access. WEBrick supports both basic and digest authentication in addition to algorithms not in RFC 2617.

A WEBrick server can be composed of multiple WEBrick servers or servlets to provide differing behavior on a per-host or per-path basis. WEBrick includes servlets for handling CGI scripts, ERB pages, Ruby blocks and directory listings.

WEBrick also includes tools for daemonizing a process and starting a process at a higher privilege level and dropping permissions.

Starting an HTTP server

To create a new WEBrick::HTTPServer that will listen to connections on port 8000 and serve documents from the current user’s public_html folder:

require 'webrick'

root = File.expand_path '~/public_html'
server = WEBrick::HTTPServer.new :Port => 8000, :DocumentRoot => root

To run the server you will need to provide a suitable shutdown hook as starting the server blocks the current thread:

trap 'INT' do server.shutdown end

server.start

Custom Behavior

The easiest way to have a server perform custom operations is through WEBrick::HTTPServer#mount_proc. The block given will be called with a WEBrick::HTTPRequest with request info and a WEBrick::HTTPResponse which must be filled in appropriately:

server.mount_proc '/' do |req, res|
  res.body = 'Hello, world!'
end

Remember that server.mount_proc must precede server.start.

Servlets

Advanced custom behavior can be obtained through mounting a subclass of WEBrick::HTTPServlet::AbstractServlet. Servlets provide more modularity when writing an HTTP server than mount_proc allows. Here is a simple servlet:

class Simple < WEBrick::HTTPServlet::AbstractServlet
  def do_GET request, response
    status, content_type, body = do_stuff_with request

    response.status = 200
    response['Content-Type'] = 'text/plain'
    response.body = 'Hello, World!'
  end
end

To initialize the servlet you mount it on the server:

server.mount '/simple', Simple

See WEBrick::HTTPServlet::AbstractServlet for more details.

Virtual Hosts

A server can act as a virtual host for multiple host names. After creating the listening host, additional hosts that do not listen can be created and attached as virtual hosts:

server = WEBrick::HTTPServer.new # ...

vhost = WEBrick::HTTPServer.new :ServerName => 'vhost.example',
                                :DoNotListen => true, # ...
vhost.mount '/', ...

server.virtual_host vhost

If no :DocumentRoot is provided and no servlets or procs are mounted on the main server it will return 404 for all URLs.

HTTPS

To create an HTTPS server you only need to enable SSL and provide an SSL certificate name:

require 'webrick'
require 'webrick/https'

cert_name = [
  %w[CN localhost],
]

server = WEBrick::HTTPServer.new(:Port => 8000,
                                 :SSLEnable => true,
                                 :SSLCertName => cert_name)

This will start the server with a self-generated self-signed certificate. The certificate will be changed every time the server is restarted.

To create a server with a pre-determined key and certificate you can provide them:

require 'webrick'
require 'webrick/https'
require 'openssl'

cert = OpenSSL::X509::Certificate.new File.read '/path/to/cert.pem'
pkey = OpenSSL::PKey::RSA.new File.read '/path/to/pkey.pem'

server = WEBrick::HTTPServer.new(:Port => 8000,
                                 :SSLEnable => true,
                                 :SSLCertificate => cert,
                                 :SSLPrivateKey => pkey)

Proxy Server

WEBrick can act as a proxy server:

require 'webrick'
require 'webrick/httpproxy'

proxy = WEBrick::HTTPProxyServer.new :Port => 8000

trap 'INT' do proxy.shutdown end

See WEBrick::HTTPProxy for further details including modifying proxied responses.

Basic and Digest authentication

WEBrick provides both Basic and Digest authentication for regular and proxy servers. See WEBrick::HTTPAuth, WEBrick::HTTPAuth::BasicAuth and WEBrick::HTTPAuth::DigestAuth.

WEBrick as a Production Web Server

WEBrick can be run as a production server for small loads.

Daemonizing

To start a WEBrick server as a daemon simple run WEBrick::Daemon.start before starting the server.

Dropping Permissions

WEBrick can be started as one user to gain permission to bind to port 80 or 443 for serving HTTP or HTTPS traffic then can drop these permissions for regular operation. To listen on all interfaces for HTTP traffic:

sockets = WEBrick::Utils.create_listeners nil, 80

Then drop privileges:

WEBrick::Utils.su 'www'

Then create a server that does not listen by default:

server = WEBrick::HTTPServer.new :DoNotListen => true, # ...

Then overwrite the listening sockets with the port 80 sockets:

server.listeners.replace sockets

Logging

WEBrick can separately log server operations and end-user access. For server operations:

log_file = File.open '/var/log/webrick.log', 'a+'
log = WEBrick::Log.new log_file

For user access logging:

access_log = [
  [log_file, WEBrick::AccessLog::COMBINED_LOG_FORMAT],
]

server = WEBrick::HTTPServer.new :Logger => log, :AccessLog => access_log

See WEBrick::AccessLog for further log formats.

Log Rotation

To rotate logs in WEBrick on a HUP signal (like syslogd can send), open the log file in ‘a+’ mode (as above) and trap ‘HUP’ to reopen the log file:

trap 'HUP' do log_file.reopen '/path/to/webrick.log', 'a+'

Copyright

Author: IPR – Internet Programming with Ruby – writers

Copyright © 2000 TAKAHASHI Masayoshi, GOTOU YUUZOU Copyright © 2002 Internet Programming with Ruby writers. All rights reserved.

WIN32OLE_EVENT objects controls OLE event.

WIN32OLE_METHOD objects represent OLE method information.

WIN32OLE_PARAM objects represent param information of the OLE method.

WIN32OLE_RECORD objects represents VT_RECORD OLE variant. Win32OLE returns WIN32OLE_RECORD object if the result value of invoking OLE methods.

If COM server in VB.NET ComServer project is the following:

Imports System.Runtime.InteropServices
Public Class ComClass
    Public Structure Book
        <MarshalAs(UnmanagedType.BStr)> _
        Public title As String
        Public cost As Integer
    End Structure
    Public Function getBook() As Book
        Dim book As New Book
        book.title = "The Ruby Book"
        book.cost = 20
        Return book
    End Function
End Class

then, you can retrieve getBook return value from the following Ruby script:

require 'win32ole'
obj = WIN32OLE.new('ComServer.ComClass')
book = obj.getBook
book.class # => WIN32OLE_RECORD
book.title # => "The Ruby Book"
book.cost  # => 20

WIN32OLE_TYPE objects represent OLE type libarary information.

WIN32OLE_TYPELIB objects represent OLE tyblib information.

Fiddle::Pointer is a class to handle C pointers

This class is used as a return value from ObjectSpace::reachable_objects_from.

When ObjectSpace::reachable_objects_from returns an object with references to an internal object, an instance of this class is returned.

You can use the type method to check the type of the internal object.