A guide to Ruby's stdlib and available alternatives.
Please note: The standard library was turned into gems, see stdgems.org for up-to-date information on all standard gems!
Standard Library Overview
| Library | Sources | Description | Alternatives |
|---|---|---|---|
| abbrev | mri | Small library that finds the shortest abbreviation to identify one string amongst many | - |
| base64 | mri | Encodes and decodes strings to a Base64 representation. Implemented as a small wrapper around String#unpack | - |
| continuation | mri | Deprecated library that adds the goto-like Kernel#callcc | Concurrent Ruby, Fiber |
| coverage c | mri | Measures code coverage | - |
| debug | mri | Command-line debugger | byebug |
| digest c | mri | Provides common hash functions like MD5, SHA1, SHA2, or RIPEMD-160 | OpenSSL::Digest |
| drb | mri | Distributed object system for Ruby | - |
| English | mri | Readable aliases for special global variables | - |
| erb | mri | Templating engine for Ruby | erubis, erbse, erubi |
| expect | mri | Adds IO#expect, which can be used to wait for a specific pattern to be read | - |
| fiber c | mri | Adds Fiber#transfer and Fiber#alive? | - |
| find | mri | Finds all files in a given directory and its sub-directories | `find .`.split($/) |
| io/nonblock c | mri | Allows to work with IO streams in a non-blocking way |
- |
| io/wait c | mri | Adds methods to wait until an IO stream becomes readable or writable |
- |
| mkmf | mri | Generates Makefiles for native C extensions | - |
| monitor | mri | Monitors for multi-threaded code | - |
| net/ftp | mri | Support for FTP (File Transfer Protocol) | - |
| net/http | mri | Support for HTTP (Hypertext Transfer Protocol) | http.rb, em-http-request, excon, httpclient |
| net/imap | mri | Support for IMAP (Internet Message Access Protocol) | em-imap |
| nkf c | mri | Kanji encoding converter | - |
| objspace c | mri | Adds more statistics methods to ObjectSpace |
- |
| open-uri | mri | Monkeypatches Kernel#open to support remote endpoints via net/http and net/ftp |
- |
| optparse | mri | Command-line option parser | slop, optimist, clap, rationalist |
| pathname c | mri | Wraps File, FileTest, Dir, and FileUtils to ease working with file system paths |
path |
| prettyprint | mri | Better object formatting and inspection. Comes with the pp print debugging helper via require 'pp' |
wirb, hirb, awesome_print |
| profiler | mri | Measures which methods are called and how long each method takes to complete. Auto-start via require 'profile' |
ruby-prof, perftools.rb, method_profiler |
| pty c | mri | Manages pseudo terminals | - |
| racc c | mri gem |
A YACC-like LALR(1) parser generator | parslet, citrus, treetop |
| rbconfig | - | RbConfig is a Ruby constant that contains compile time information |
- |
| resolv | mri | Thread-aware DNS resolver. Will replace Socket's DNS via require 'resolve-replace' |
rubydns, net-dns, em-resolve-replace |
| rinda | mri | Support fot the Linda distributed computing paradigm in drb | - |
| ripper c | mri | Ruby parser that creates a symbolic expression tree | ruby_parser, parser |
| securerandom | mri | Provides crpytographical randomness from openssl or the OS | - |
| set | mri | Data structure for unordered collections without duplicates. Implemented on top of Hash. Also comes with SortedSet for ordered collections. | - |
| shellwords | mri | Escape and manipulate commands to be run in the shell | - |
| socket c | mri | Support for unix- and network sockets | - |
| syslog c | mri | Interface to the low-level syslog logger | syslogger, log4r, lumberjack_syslog_device, yell-adapters-syslog |
| tempfile | mri | Simplifies OS independent creation of temporary files | - |
| time | mri | Adds more methods to Time |
- |
| tmpdir | mri | Adds a Dir.mktmpdir method for creating temporary directories OS independently |
- |
| tsort | mri | Typological sorting using Tarjan’s algorithm, which finds strongly connected components in graphs | - |
| un | mri | Utilities to replace common UNIX commands | - |
| unicode_normalize (auto-require) |
mri | Adds a String#unicode_normalize method which normalizes unicode strings | unf, unicode |
| weakref | mri | Explicitly allow objects to be garbage collected | ref |
| Win32API c | mri | Let's you use Windows APIs, like calling functions in DLLs | win32-api, ffi |
| win32ole c | mri | Windows OLE automation interface | - |
Default Gems
These libraries come as default Ruby gems, so that they can be updated independently from Ruby. See stdgems.org for more info.
| Gem | Sources | Description | Alternatives |
|---|---|---|---|
| benchmark | mri gem |
Benchmarking library | benchmark-ips, benchmark-driver |
| bigdecimal c | mri gem |
Support for arbitrary-precision floating point decimal arithmetic | - |
| bundler | mri gem |
Bundler is the local package manager for Ruby applications | - |
| cgi | mri gem |
Support for CGI (Common Gateway Interface) | rack |
| csv | mri gem |
Support for CSV (Comma-separated Values) | smarter_csv |
| date c | mri gem |
The Date and DateTime classes | - |
| dbm c | mri gem |
Support for DBM databases | - |
| delegate | mri gem |
Provides three ways to delegate method calls | forwardable |
| did_you_mean (auto-require) |
mri gem |
Patches error messages to suggest correct spelling of methods/classes/variables | - |
| etc c | mri gem |
Access UNIX info from /etc |
- |
| fcntl c | mri gem |
Loads values from the OS' fcntl.h to be used for low-level file descriptor manipulation system calls with IO#fcntl and IO.sysopen |
- |
| fiddle c | mri gem |
Support for FFI (Foreign Function Interface) | ffi |
| fileutils | mri gem |
Utilities for working with the file system | - |
| forwardable | mri gem |
Provides a way to delegate method calls. Also see this overview of delegation in Ruby, which contains an example | - |
| gdbm c | mri gem |
Support for GNU dbm databases | - |
| getoptlong | mri gem |
GNU getopt_long() style command-line option parsing | OptParse, slop, optimist, clap, rationalist |
| io/console c | mri gem |
Patches IO for simple and portable access to the console |
- |
| ipaddr | mri gem |
IP address manipulation | ipaddress, ruby-ip |
| irb | mri | Interactive Ruby Console (REPL) | ripl, pry, rib |
| json c | mri gem |
Support for JSON (JavaScript Object Notation) | oj, yajl-ruby |
| logger | mri gem |
Logging utility | log4r, lumberjack, yell, logging, micrologger |
| matrix | mri gem |
Support for matrices | nmatrix |
| mutex_m | mri gem |
A mixin that makes any object behave like a mutex | - |
| observer | mri gem |
Implementation of the observer pattern, a way to let interested other objects know o an object's updates | microevent, signal_lamp |
| net/pop | mri gem |
Support for POP3 (Post Office Protocol) | - |
| net/smtp | mri gem |
Support for SMTP (Simple Mail Transfer Protocol) | - |
| open3 | mri gem |
Simple spawning of child processes | open4 |
| openssl c | mri gem |
Wraps OpenSSL for cryptographic functionality | - |
| ostruct | mri gem |
Wrapper around Hash that lets you read and set attributes with a method API | Hash, ostruct2 |
| prime | mri gem |
Access to prime numbers and prime factorization | - |
| pstore | mri gem |
Transactional file storage for Ruby objects | - |
| psych c | mri gem |
Support for YAML (YAML Ain't Markup Language) | - |
| rdoc | mri gem |
Ruby documentation generator | yard |
| readline | mri gem |
If available, readline-ext will be loaded, or (Ruby-only) reline will be used | - |
| readline-ext | mri gem |
Interface to GNU Readline and NetBSD Editline | rb-readline, reline |
| reline | mri gem |
Ruby-only implementation of GNU Readline / NetBSD Editline | rb-readline |
| rexml | mri gem |
Support for XML (Extensible Markup Language) | nokogiri, oga |
| rss | mri gem |
Support for RSS (Rich Site Summary) and Atom | - |
| rubygems (auto-require) |
mri gem |
Manages Ruby libraries. | - |
| sdbm c | mri gem |
Support for SDBM databases | - |
| singleton | mri gem |
Mixin for Ruby classes that should only have one instance | - |
| stringio c | mri gem |
Makes strings behave like IO objects | - |
| strscan c | mri gem |
Lexical string scanning | - |
| timeout | mri gem |
Auto-terminates code blocks after the time limit is reached | - |
| tracer | mri gem |
Outputs the code execution trace via Kernel#set_trace_func | TracePoint |
| uri | mri gem |
URI/URL manipulation | addressable,ruby-uriparser |
| webrick | mri gem |
HTTP server | thin, unicorn, puma |
| yaml | mri gem |
Loads the psych yaml parser and sets YAML = Psych |
- |
| zlib c | mri gem |
Interface to the zlib compression library | - |
Bundled Gems
Gems that will be installed together with Ruby. See stdgems.org for more info.
| Gem | Description | Alternatives |
|---|---|---|
| minitest | Test/spec framework, comes with mocking and benchmark capabilities | rspec |
| net-telnet | Support for Telnet | - |
| power_assert | Debug tool that displays intermediate results of a method chain | - |
| rake | A Ruby task runner, inspired by make | thor, boson |
| test-unit | A xUnit family unit testing framework | minitest, rspec |
| xmlrpc | Remote Procedure Calls via XML and HTTP | - |
Something's wrong or missing? You can edit this list on GitHub!
Resources
- RDoc: Standard library short descriptions
- RDoc: Standard library maintainers
- About standard library gems
- Standard Gems Data
More Idiosyncratic Ruby
- Please Comment on GitHub
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