Raised when a command was found, but not invoked properly.
Outputs a source level execution trace of a Ruby program.
It does this by registering an event handler with Kernel#set_trace_func for processing incoming events. It also provides methods for filtering unwanted trace output (see Tracer.add_filter, Tracer.on, and Tracer.off).
Consider the following Ruby script
class A def square(a) return a*a end end a = A.new a.square(5)
Running the above script using ruby -r tracer example.rb will output the following trace to STDOUT (Note you can also explicitly require 'tracer')
#0:<internal:lib/rubygems/custom_require>:38:Kernel:<: - #0:example.rb:3::-: class A #0:example.rb:3::C: class A #0:example.rb:4::-: def square(a) #0:example.rb:7::E: end #0:example.rb:9::-: a = A.new #0:example.rb:10::-: a.square(5) #0:example.rb:4:A:>: def square(a) #0:example.rb:5:A:-: return a*a #0:example.rb:6:A:<: end | | | | | | | | | ---------------------+ event | | | ------------------------+ class | | --------------------------+ line | ------------------------------------+ filename ---------------------------------------+ thread
Symbol table used for displaying incoming events:
call a C-language routine
return from a C-language routine
call a Ruby method
C
start a class or module definition
E
finish a class or module definition
-
execute code on a new line
raise an exception
return from a Ruby method
by Keiju ISHITSUKA(keiju@ishitsuka.com)
The GetoptLong class allows you to parse command line options similarly to the GNU getopt_long() C library call. Note, however, that GetoptLong is a pure Ruby implementation.
GetoptLong allows for POSIX-style options like --file as well as single letter options like -f
The empty option -- (two minus symbols) is used to end option processing. This can be particularly important if options have optional arguments.
Here is a simple example of usage:
require 'getoptlong' opts = GetoptLong.new( [ '--help', '-h', GetoptLong::NO_ARGUMENT ], [ '--repeat', '-n', GetoptLong::REQUIRED_ARGUMENT ], [ '--name', GetoptLong::OPTIONAL_ARGUMENT ] ) dir = nil name = nil repetitions = 1 opts.each do |opt, arg| case opt when '--help' puts <<-EOF hello [OPTION] ... DIR -h, --help: show help --repeat x, -n x: repeat x times --name [name]: greet user by name, if name not supplied default is John DIR: The directory in which to issue the greeting. EOF when '--repeat' repetitions = arg.to_i when '--name' if arg == '' name = 'John' else name = arg end end end if ARGV.length != 1 puts "Missing dir argument (try --help)" exit 0 end dir = ARGV.shift Dir.chdir(dir) for i in (1..repetitions) print "Hello" if name print ", #{name}" end puts end
Example command line:
hello -n 6 --name -- /tmp
The set of all prime numbers.
Prime.each(100) do |prime| p prime #=> 2, 3, 5, 7, 11, ...., 97 end
Prime is Enumerable:
Prime.first 5 # => [2, 3, 5, 7, 11]
For convenience, each instance method of Prime.instance can be accessed as a class method of Prime.
e.g.
Prime.instance.prime?(2) #=> true Prime.prime?(2) #=> true
A “generator” provides an implementation of enumerating pseudo-prime numbers and it remembers the position of enumeration and upper bound. Furthermore, it is an external iterator of prime enumeration which is compatible with an Enumerator.
Prime::PseudoPrimeGenerator is the base class for generators. There are few implementations of generator.
Prime::EratosthenesGenerator
Uses eratosthenes’ sieve.
Prime::TrialDivisionGenerator
Uses the trial division method.
Prime::Generator23
Generates all positive integers which are not divisible by either 2 or 3. This sequence is very bad as a pseudo-prime sequence. But this is faster and uses much less memory than the other generators. So, it is suitable for factorizing an integer which is not large but has many prime factors. e.g. for Prime#prime? .
PStore implements a file based persistence mechanism based on a Hash. User code can store hierarchies of Ruby objects (values) into the data store file by name (keys). An object hierarchy may be just a single object. User code may later read values back from the data store or even update data, as needed.
The transactional behavior ensures that any changes succeed or fail together. This can be used to ensure that the data store is not left in a transitory state, where some values were updated but others were not.
Behind the scenes, Ruby objects are stored to the data store file with Marshal. That carries the usual limitations. Proc objects cannot be marshalled, for example.
require "pstore" # a mock wiki object... class WikiPage def initialize( page_name, author, contents ) @page_name = page_name @revisions = Array.new add_revision(author, contents) end attr_reader :page_name def add_revision( author, contents ) @revisions << { :created => Time.now, :author => author, :contents => contents } end def wiki_page_references [@page_name] + @revisions.last[:contents].scan(/\b(?:[A-Z]+[a-z]+){2,}/) end # ... end # create a new page... home_page = WikiPage.new( "HomePage", "James Edward Gray II", "A page about the JoysOfDocumentation..." ) # then we want to update page data and the index together, or not at all... wiki = PStore.new("wiki_pages.pstore") wiki.transaction do # begin transaction; do all of this or none of it # store page... wiki[home_page.page_name] = home_page # ensure that an index has been created... wiki[:wiki_index] ||= Array.new # update wiki index... wiki[:wiki_index].push(*home_page.wiki_page_references) end # commit changes to wiki data store file ### Some time later... ### # read wiki data... wiki.transaction(true) do # begin read-only transaction, no changes allowed wiki.roots.each do |data_root_name| p data_root_name p wiki[data_root_name] end end
By default, file integrity is only ensured as long as the operating system (and the underlying hardware) doesn’t raise any unexpected I/O errors. If an I/O error occurs while PStore is writing to its file, then the file will become corrupted.
You can prevent this by setting pstore.ultra_safe = true. However, this results in a minor performance loss, and only works on platforms that support atomic file renames. Please consult the documentation for ultra_safe for details.
Needless to say, if you’re storing valuable data with PStore, then you should backup the PStore files from time to time.
Raised when attempting to convert special float values (in particular Infinity or NaN) to numerical classes which don’t support them.
Float::INFINITY.to_r #=> FloatDomainError: Infinity
The global value true is the only instance of class TrueClass and represents a logically true value in boolean expressions. The class provides operators allowing true to be used in logical expressions.
ConditionVariable objects augment class Mutex. Using condition variables, it is possible to suspend while in the middle of a critical section until a resource becomes available.
Example:
mutex = Mutex.new resource = ConditionVariable.new a = Thread.new { mutex.synchronize { # Thread 'a' now needs the resource resource.wait(mutex) # 'a' can now have the resource } } b = Thread.new { mutex.synchronize { # Thread 'b' has finished using the resource resource.signal } }
This module provides a framework for message digest libraries.
You may want to look at OpenSSL::Digest as it supports more algorithms.
A cryptographic hash function is a procedure that takes data and returns a fixed bit string: the hash value, also known as digest. Hash functions are also called one-way functions, it is easy to compute a digest from a message, but it is infeasible to generate a message from a digest.
require 'digest' # Compute a complete digest Digest::SHA256.digest 'message' #=> "\xABS\n\x13\xE4Y..." sha256 = Digest::SHA256.new sha256.digest 'message' #=> "\xABS\n\x13\xE4Y..." # Other encoding formats Digest::SHA256.hexdigest 'message' #=> "ab530a13e459..." Digest::SHA256.base64digest 'message' #=> "q1MKE+RZFJgr..." # Compute digest by chunks md5 = Digest::MD5.new md5.update 'message1' md5 << 'message2' # << is an alias for update md5.hexdigest #=> "94af09c09bb9..." # Compute digest for a file sha256 = Digest::SHA256.file 'testfile' sha256.hexdigest
Additionally digests can be encoded in “bubble babble” format as a sequence of consonants and vowels which is more recognizable and comparable than a hexadecimal digest.
require 'digest/bubblebabble' Digest::SHA256.bubblebabble 'message' #=> "xopoh-fedac-fenyh-..."
See the bubble babble specification at web.mit.edu/kenta/www/one/bubblebabble/spec/jrtrjwzi/draft-huima-01.txt.
Digest algorithms Different digest algorithms (or hash functions) are available:
MD5
See RFC 1321 The MD5 Message-Digest Algorithm
As Digest::RMD160. See homes.esat.kuleuven.be/~bosselae/ripemd160.html.
SHA1
See FIPS 180 Secure Hash Standard.
See FIPS 180 Secure Hash Standard which defines the following algorithms:
SHA512
SHA384
SHA256
The latest versions of the FIPS publications can be found here: csrc.nist.gov/publications/PubsFIPS.html.
The Readline module provides interface for GNU Readline. This module defines a number of methods to facilitate completion and accesses input history from the Ruby interpreter. This module supported Edit Line(libedit) too. libedit is compatible with GNU Readline.
Reads one inputted line with line edit by Readline.readline method. At this time, the facilitatation completion and the key bind like Emacs can be operated like GNU Readline.
require "readline" while buf = Readline.readline("> ", true) p buf end
The content that the user input can be recorded to the history. The history can be accessed by Readline::HISTORY constant.
require "readline" while buf = Readline.readline("> ", true) p Readline::HISTORY.to_a print("-> ", buf, "\n") end
Documented by Kouji Takao <kouji dot takao at gmail dot com>.
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 $_ using less cryptic names, listed below.
Without ‘English’:
$\ = ' -- ' "waterbuffalo" =~ /buff/ print $', $$, "\n"
With English:
require "English" $OUTPUT_FIELD_SEPARATOR = ' -- ' "waterbuffalo" =~ /buff/ print $POSTMATCH, $PID, "\n"
Below is a full list of descriptive aliases and their associated global variable:
$!
$@
$;
$;
$,
$,
$/
$/
$\
$\
$.
$.
$_
$>
$<
$$
$$
$?
$~
$=
$*
$&
$‘
$‘
$+
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).start_with?('.') Find.prune # Don't look any further into this directory. else next end else total_size += FileTest.size(path) end end
URI is a module providing classes to handle Uniform Resource Identifiers (RFC2396).
Uniform way of handling URIs.
Flexibility to introduce custom URI schemes.
Flexibility to have an alternate URI::Parser (or just different patterns and regexp’s).
require 'uri' uri = URI("http://foo.com/posts?id=30&limit=5#time=1305298413") #=> #<URI::HTTP 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"
module URI class RSYNC < Generic DEFAULT_PORT = 873 end @@schemes['RSYNC'] = RSYNC end #=> URI::RSYNC URI.scheme_list #=> {"FILE"=>URI::File, "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 rsync://rsync.foo.com>
A good place to view an RFC spec is www.ietf.org/rfc.html.
Here is a list of all related RFC’s:
Class tree URI::Generic (in uri/generic.rb)
URI::File - (in uri/file.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)
Akira Yamada <akira@ruby-lang.org>
Akira Yamada <akira@ruby-lang.org> Dmitry V. Sabanin <sdmitry@lrn.ru> Vincent Batts <vbatts@hashbangbash.com>
Copyright © 2001 akira yamada <akira@ruby-lang.org> You can redistribute it and/or modify it under the same term as Ruby.
$Id$
OpenURI is an easy-to-use wrapper for Net::HTTP, Net::HTTPS and Net::FTP.
It is possible to open an http, https or ftp URL as though it were a file:
URI.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.
URI.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.
URI.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:
URI.open("http://www.ruby-lang.org/en/", :proxy => nil) {|f| # ... }
See OpenURI::OpenRead.open and URI.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
Tanaka Akira <akr@m17n.org>
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.
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
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.
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.
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.
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)
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.
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.
To start a WEBrick server as a daemon simple run WEBrick::Daemon.start before starting the server.
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
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+'
Author: IPR – Internet Programming with Ruby – writers
Copyright © 2000 TAKAHASHI Masayoshi, GOTOU YUUZOU Copyright © 2002 Internet Programming with Ruby writers. All rights reserved.