Difference between revisions of "Ruby"

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[[Category:Programming language]]
 
[[Category:Programming language]]
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[[ja:Ruby]]
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[[zh-CN:Ruby]]
 
Ruby is a dynamic, interpreted, open source programming language with a focus on simplicity and productivity.
 
Ruby is a dynamic, interpreted, open source programming language with a focus on simplicity and productivity.
  
 
== Installing Ruby ==
 
== Installing Ruby ==
The version of Ruby you need to install depends on your requirements, as not all 3rd party code is compatible with all versions. Here is a summary of the versions below and how to get them:
 
  
=== Ruby 1.9 (Development) ===
+
The version of Ruby you need to install depends on your requirements. If you are supporting a legacy application, install Ruby 2.0 or 1.9 as necessary. If you are starting a new project, Ruby 2.1 is recommended. Below is a summary of the available versions and how to get them.
'''Summary:''' Use Ruby 1.9 for a new Rails project, or when you are sure all your required gems are supported by Ruby 1.9
+
  
Pros:
+
=== Ruby 2.1 ===
* Vastly improved performance over 1.8
+
* New features for concurrency such as fibers.
+
* Various other language improvements, such as an improved CSV parser.
+
  
Cons:
+
To install Ruby 2.1, install {{Pkg|ruby}}. Ruby 2.1 includes [[#RubyGems|RubyGems]].
* Not compatible with many older gems (and Ruby On Rails versions prior to 2.3)
+
* Changes in the language might cause older Ruby code not to run, or exhibit unexpected bugs.
+
  
{{Note|Visit http://isitruby19.com/ to determine if the gems/modules you require are compatible with Ruby 1.9.}}
+
=== Ruby 2.0 ===
  
To install Ruby 1.9, simply install {{Pkg|ruby}}.
+
To install Ruby 2.0, install {{AUR|ruby2.0}} from the [[AUR]]. Ruby 2.0 includes RubyGems.
  
Ruby 1.9 also includes RubyGems (detailed below), so you can easily update to the latest RubyGems using:
+
=== Ruby 1.9 ===
# gem update --system
+
  
=== Ruby 1.8.7 (Stable) ===
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To install Ruby 1.9, install {{AUR|ruby1.9}} from the [[AUR]]. Ruby 1.9 includes RubyGems.
'''Summary:''' Use Ruby 1.8.7 if you are unsure, or are not working on any legacy systems.
+
  
Pros:
+
=== Multiple versions ===
* Latest version of the 1.8 branch, capable of running most if not all recently updated gems and Ruby On Rails
+
  
Cons:
+
If you want to run multiple versions on the same system (e.g. 2.0.0-p0 and 1.9.3-p392), the easiest way is to use [[RVM]] or [[rbenv]].
* Introduces certain breaking changes from 1.8.6, which causes older lesser-maintained gems and Rails prior to 2.0 not to work without "monkey patching".
+
  
You can install {{AUR|ruby-1.8.7-svn}} or {{AUR|ruby1.8}} from the [[AUR]].
+
=== Documentation ===
  
RubyGems is not included with the {{AUR|ruby1.8}} package, so install {{AUR|rubygems1.8}} from the [[AUR]].
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To make documentation available through the included {{ic|ri}} command-line tool, install {{Pkg|ruby-docs}}.
 +
You can then query the docs with: {{ic|ri Array}}, {{ic|ri Array.pop}} etc. (much like man-pages)
  
=== Ruby 1.8.6 (Legacy) ===
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== RubyGems ==
'''Summary:''' Use Ruby 1.8.6 if you are working on old projects, older version of Rails (especially < 2.0), or simply want the least possible issues.
+
  
Pros:
+
RubyGems is a package manager for Ruby modules (called ''gems''), somewhat comparable to what [[pacman]] is to Arch Linux. It is included in the {{pkg|ruby}} package.
* Compatible with just about anything
+
  
Cons:
+
=== Setup ===
* Missing some performance and language enhancements from 1.8.7
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* Support might be dropped with Rails 3.0 (in Beta at the time of writing)
+
  
You can install {{AUR|ruby1.8.6-legacy}} from the [[AUR]].  
+
Before you use RubyGems, you need to add {{ic|$(ruby -rubygems -e "puts Gem.user_dir")/bin}} to your {{ic|$PATH}}. You can do this by adding the following line to {{ic|~/.bashrc}}:
 +
PATH="$(ruby -e 'puts Gem.user_dir')/bin:$PATH"
  
RubyGems is not included with the ruby1.8.6-legacy package, so install {{AUR|rubygems1.8}} from the [[AUR]].
+
=== Usage ===
  
{{Note|This package will replace the official {{Pkg|ruby}} package, as installing both Ruby 1.8 and 1.9, while possible, can cause erratic behavior of some 3rd party code.}}
+
To see what gems are installed:
 +
$ gem list
  
=== Multiple versions ===
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To get information about a gem:
If you want to run multiple versions on the same system (e.g. '''1.9.1''' and '''1.8.7'''), the easiest way is to use [[RVM]].
+
$ gem spec ''gem_name''
  
== RubyGems ==
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By default, {{ic|gem list}} and {{ic|gem spec}} use the {{ic|--local}} option, which forces ''gem'' to search only the local system. This can be overridden with the {{ic|--remote}} flag. Thus, to search for the mysql gem:
''gem'' is the package manager of sorts for Ruby modules (called Gems), somewhat comparable to what pacman is to Arch Linux. The ''gem'' command will be installed if you followed the installation instructions above.
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$ gem list --remote mysql
  
=== Running as normal user ===
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To install a gem:
When running ''gem'' as a user, the gems will be installed into {{ic|~/.gem}} and not affect anyone else, although it might be worth noting that not all gems are happy with being installed in this way, and might insist on being installed by root (especially if they have native extensions). This is considered the best way to manage gems on Arch.
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  $ gem install mysql
  
To use gems which install binaries, you need to add {{ic|~/.gem/ruby/1.9.1/bin}} to your {{ic|$PATH}}.
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The process can be sped up somewhat if you do not need local documentation:
 +
$ gem install mysql --no-rdoc --no-ri
  
This per-user behavior is enabled via {{ic|/etc/gemrc}} and can be overridden by a {{ic|~/.gemrc}} file.
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{{Note|This can be made the default option by configuring the following {{ic|~/.gemrc}} file:
 
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{{hc|~/.gemrc|<nowiki>
=== Running as root ===
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gem: --no-rdoc --no-ri
When running gem as root, gems will be installed for everyone on the machine. However, this tends to leave out-of-date executables littering the filesystem, and updating or installing gems without everyone's knowledge (like on a shared server) might cause Ruby applications to break.
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</nowiki>}}
 
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}}
[[Ruby#Bundler|Bundler]] solves these problems to some extent by packaging gems into your application. See the section below on using bundler.
+
  
=== Updating RubyGems ===
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To update all installed gems:
 
  $ gem update
 
  $ gem update
  
=== Installing a gem ===
+
=== Installing gems per-user or system-wide ===
This example installs the MySQL ruby gem:
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$ gem install mysql
+
  
The process can be sped up somewhat if you do not need local documentation:
+
By default in Arch Linux, when running {{ic|gem}}, gems are installed per-user (into {{ic|~/.gem/ruby/}}), instead of system-wide (into {{ic|/usr/lib/ruby/gems/}}). This is considered the best way to manage gems on Arch, because otherwise they might interfere with gems installed by Pacman.
$ gem install mysql --no-rdoc --no-ri
+
  
The gem will now be downloaded, compiled if necessary, and installed.
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Gems can be installed system wide by running the {{ic|gem}} command as root, appended with the {{ic|--no-user-install}} flag. This flag can be set as default by replacing {{ic|--user-install}} by {{ic|--no-user-install}} in {{ic|/etc/gemrc}} (system-wide) or {{ic|~/.gemrc}} (per-user, overrides system-wide).
 +
 
 +
[[#Bundler|Bundler]] solves these problems to some extent by packaging gems into your application. See the section below on using bundler.
  
 
=== Bundler ===
 
=== Bundler ===
[http://github.com/carlhuda/bundler Bundler] installs gems (including those with native extensions) directly into your application, which works very well for shared hosting and easy deployment of [[Ruby on Rails]] applications for example. Bundler also resolves dependencies as a whole, rather than individually like RubyGems, making things a lot easier. To install:
+
 
 +
[http://github.com/carlhuda/bundler Bundler] allows you to specify which gems your application depends upon, and optionally which version those gems should be. Once this specification is in place, Bundler installs all required gems (including the full gem dependency tree) and logs the results for later inspection. By default, Bundler installs gems into a shared location, but they can also be installed directly into your application. When your application is run, Bundler provides the correct version of each gem, even if multiple versions of each gem have been installed. This requires a little bit of work: applications should be called with {{ic|bundle exec}}, and two lines of boilerplate code must be placed in your application's main executable.
 +
 
 +
To install Bundler:
 
  $ gem install bundler
 
  $ gem install bundler
  
Bundler seems to want to install gems system-wide, contrary to the current default behaviour of ''gem'' itself on Arch. To correct this, add the following line to your {{ic|~/.bashrc}}:
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By default, Bundler installs gems system-wide, which is contrary to the behaviour of ''gem'' itself on Arch. To correct this, add the following to your {{ic|~/.bashrc}}:
  export GEM_HOME="~/.gem/ruby/1.9.1"
+
  export GEM_HOME=$(ruby -e 'puts Gem.user_dir')
  
 
To start a new bundle:
 
To start a new bundle:
 
  $ bundle init
 
  $ bundle init
  
Then add your required gems into "Gemfile" in the current directory (created by bundle init):
+
Then edit {{ic|Gemfile}} in the current directory (created by bundle init) and list your required gems:
 
+
 
{{hc|Gemfile|
 
{{hc|Gemfile|
gem "rails", "2.3.4"
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gem "rails", "3.2.9"
 
gem "mysql"
 
gem "mysql"
 
}}
 
}}
  
Finally, run the following to install your gems:
+
Run the following to install gems into {{ic|GEM_HOME}}:
 
  $ bundle install
 
  $ bundle install
  
Or, alternatively, in order to install locally to {{ic|.bundle}} under the working directory:
+
Alternatively, run the following to install gems to {{ic|.bundle}} in the working directory:
 
  $ bundle install --path .bundle
 
  $ bundle install --path .bundle
  
== Managing RubyGems using pacman ==
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Don't forget to edit your main executable:
 +
{{bc|#!/usr/bin/env ruby
 +
 
 +
# "This will automatically discover your Gemfile, and make all of the gems in
 +
# your Gemfile available to Ruby." http://gembundler.com/v1.3/rationale.html
 +
require 'rubygems'
 +
require 'bundler/setup'
 +
 
 +
...
 +
}}
 +
 
 +
Finally, run your program:
 +
bundle exec ''main_executable_name.rb''
 +
 
 +
=== Managing RubyGems using pacman ===
 +
 
 +
Instead of managing gems with {{ic|gem}}, you can use {{ic|pacman}}, or some [[AUR]] helper. Ruby packages follow the naming convention ruby-[gemname]. This option provides the following advantages:
 +
 
 +
* Gems are updated along with the rest of your system. As a result, you never need to run {{ic|gem update}}: {{ic|# pacman -Syu}} suffices.
 +
* Installed gems are available system-wide, instead of being available only to the user who installed them.
  
Instead of using the gem command directly you can use pacman to manage the installed gems like normal packages. There are a lot of ruby packages available from [[AUR]]. Ruby packages follow the naming convention ruby-[gemname]. As an alternative you can use the tool {{AUR|pacgem}} which automatically creates arch packages from gems and installs them afterwards using pacman.
+
If a gem is not available in the repositories, you can use {{AUR|gem2arch}} or {{AUR|pacgem}} to automatically create a package, which can then be installed by pacman.
  
 
== See also ==
 
== See also ==
* [[Ruby On Rails]]
 
  
== References ==
+
* [[Ruby on Rails]]
 
* Ruby - http://ruby-lang.org/
 
* Ruby - http://ruby-lang.org/
 
* Rubyforge - http://rubyforge.org
 
* Rubyforge - http://rubyforge.org
 
* Bundler - http://github.com/carlhuda/bundler
 
* Bundler - http://github.com/carlhuda/bundler

Revision as of 09:16, 16 February 2014

Ruby is a dynamic, interpreted, open source programming language with a focus on simplicity and productivity.

Installing Ruby

The version of Ruby you need to install depends on your requirements. If you are supporting a legacy application, install Ruby 2.0 or 1.9 as necessary. If you are starting a new project, Ruby 2.1 is recommended. Below is a summary of the available versions and how to get them.

Ruby 2.1

To install Ruby 2.1, install ruby. Ruby 2.1 includes RubyGems.

Ruby 2.0

To install Ruby 2.0, install ruby2.0AUR from the AUR. Ruby 2.0 includes RubyGems.

Ruby 1.9

To install Ruby 1.9, install ruby1.9AUR from the AUR. Ruby 1.9 includes RubyGems.

Multiple versions

If you want to run multiple versions on the same system (e.g. 2.0.0-p0 and 1.9.3-p392), the easiest way is to use RVM or rbenv.

Documentation

To make documentation available through the included ri command-line tool, install ruby-docs. You can then query the docs with: ri Array, ri Array.pop etc. (much like man-pages)

RubyGems

RubyGems is a package manager for Ruby modules (called gems), somewhat comparable to what pacman is to Arch Linux. It is included in the ruby package.

Setup

Before you use RubyGems, you need to add $(ruby -rubygems -e "puts Gem.user_dir")/bin to your $PATH. You can do this by adding the following line to ~/.bashrc:

PATH="$(ruby -e 'puts Gem.user_dir')/bin:$PATH"

Usage

To see what gems are installed:

$ gem list

To get information about a gem:

$ gem spec gem_name

By default, gem list and gem spec use the --local option, which forces gem to search only the local system. This can be overridden with the --remote flag. Thus, to search for the mysql gem:

$ gem list --remote mysql

To install a gem:

$ gem install mysql

The process can be sped up somewhat if you do not need local documentation:

$ gem install mysql --no-rdoc --no-ri
Note: This can be made the default option by configuring the following ~/.gemrc file:
~/.gemrc
gem: --no-rdoc --no-ri

To update all installed gems:

$ gem update

Installing gems per-user or system-wide

By default in Arch Linux, when running gem, gems are installed per-user (into ~/.gem/ruby/), instead of system-wide (into /usr/lib/ruby/gems/). This is considered the best way to manage gems on Arch, because otherwise they might interfere with gems installed by Pacman.

Gems can be installed system wide by running the gem command as root, appended with the --no-user-install flag. This flag can be set as default by replacing --user-install by --no-user-install in /etc/gemrc (system-wide) or ~/.gemrc (per-user, overrides system-wide).

Bundler solves these problems to some extent by packaging gems into your application. See the section below on using bundler.

Bundler

Bundler allows you to specify which gems your application depends upon, and optionally which version those gems should be. Once this specification is in place, Bundler installs all required gems (including the full gem dependency tree) and logs the results for later inspection. By default, Bundler installs gems into a shared location, but they can also be installed directly into your application. When your application is run, Bundler provides the correct version of each gem, even if multiple versions of each gem have been installed. This requires a little bit of work: applications should be called with bundle exec, and two lines of boilerplate code must be placed in your application's main executable.

To install Bundler:

$ gem install bundler

By default, Bundler installs gems system-wide, which is contrary to the behaviour of gem itself on Arch. To correct this, add the following to your ~/.bashrc:

export GEM_HOME=$(ruby -e 'puts Gem.user_dir')

To start a new bundle:

$ bundle init

Then edit Gemfile in the current directory (created by bundle init) and list your required gems:

Gemfile
gem "rails", "3.2.9"
gem "mysql"

Run the following to install gems into GEM_HOME:

$ bundle install

Alternatively, run the following to install gems to .bundle in the working directory:

$ bundle install --path .bundle

Don't forget to edit your main executable:

#!/usr/bin/env ruby

# "This will automatically discover your Gemfile, and make all of the gems in
# your Gemfile available to Ruby." http://gembundler.com/v1.3/rationale.html
require 'rubygems'
require 'bundler/setup'

...

Finally, run your program:

bundle exec main_executable_name.rb

Managing RubyGems using pacman

Instead of managing gems with gem, you can use pacman, or some AUR helper. Ruby packages follow the naming convention ruby-[gemname]. This option provides the following advantages:

  • Gems are updated along with the rest of your system. As a result, you never need to run gem update: # pacman -Syu suffices.
  • Installed gems are available system-wide, instead of being available only to the user who installed them.

If a gem is not available in the repositories, you can use gem2archAUR or pacgemAUR to automatically create a package, which can then be installed by pacman.

See also