Gem::Installer does the work of putting files in all the right places on the filesystem including unpacking the gem into its gem dir, installing the gemspec in the specifications dir, storing the cached gem in the cache dir, and installing either wrappers or symlinks for executables.

The installer invokes pre and post install hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_install and Gem.post_install for details.

Gem::PackageTask

Create a package based upon a Gem::Specification. Gem packages, as well as zip files and tar/gzipped packages can be produced by this task.

In addition to the Rake targets generated by Rake::PackageTask, a Gem::PackageTask will also generate the following tasks:

“package_dir/name-version.gem”: Create a RubyGems package with the given name and version.

Example using a Gem::Specification:

require 'rubygems'
require 'rubygems/package_task'

spec = Gem::Specification.new do |s|
  s.summary = "Ruby based make-like utility."
  s.name = 'rake'
  s.version = PKG_VERSION
  s.requirements << 'none'
  s.files = PKG_FILES
  s.description = <<-EOF
Rake is a Make-like program implemented in Ruby. Tasks
and dependencies are specified in standard Ruby syntax.
  EOF
end

Gem::PackageTask.new(spec) do |pkg|
  pkg.need_zip = true
  pkg.need_tar = true
end

Gem::PathSupport

Gem::PathSupport facilitates the GEM_HOME and GEM_PATH environment settings to the rest of RubyGems.

Gem::Specification

The Specification class contains the information for a gem. Typically defined in a .gemspec file or a Rakefile, and looks like this:

Gem::Specification.new do |s|
  s.name        = 'example'
  s.version     = '0.1.0'
  s.licenses    = ['MIT']
  s.summary     = "This is an example!"
  s.description = "Much longer explanation of the example!"
  s.authors     = ["Ruby Coder"]
  s.email       = 'rubycoder@example.com'
  s.files       = ["lib/example.rb"]
  s.homepage    = 'https://rubygems.org/gems/example'
  s.metadata    = { "source_code_uri" => "https://github.com/example/example" }
end

Starting in RubyGems 2.0, a Specification can hold arbitrary metadata. See metadata for restrictions on the format and size of metadata items you may add to a specification.

Gem::SpecificationPolicy

No documentation available

Gem::SpecificationRecord

No documentation available

Gem::StubSpecification

Gem::StubSpecification reads the stub: line from the gemspec. This prevents us having to eval the entire gemspec in order to find out certain information.

Gem::Uninstaller

An Uninstaller.

The uninstaller fires pre and post uninstall hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_uninstall and Gem.post_uninstall for details.

Gem::UriFormatter

The UriFormatter handles URIs from user-input and escaping.

uf = Gem::UriFormatter.new 'example.com'

p uf.normalize #=> 'http://example.com'

SyntaxSuggest::ExplainSyntax

Explains syntax errors based on their source

example:

source = "def foo; puts 'lol'" # Note missing end
explain ExplainSyntax.new(
  code_lines: CodeLine.from_source(source)
).call
explain.errors.first
# => "Unmatched keyword, missing `end' ?"

When the error cannot be determined by lexical counting then the parser is run against the input and the raw errors are returned.

Example:

source = "1 * " # Note missing a second number
explain ExplainSyntax.new(
  code_lines: CodeLine.from_source(source)
).call
explain.errors.first
# => "syntax error, unexpected end-of-input"

SyntaxSuggest::PathnameFromMessage

Converts a SyntaxError message to a path

Handles the case where the filename has a colon in it such as on a windows file system: github.com/ruby/syntax_suggest/issues/111

Example:

message = "/tmp/scratch:2:in `require_relative': /private/tmp/bad.rb:1: syntax error, unexpected `end' (SyntaxError)"
puts PathnameFromMessage.new(message).call.name
# => "/tmp/scratch.rb"

URI::LDAP

LDAP URI SCHEMA (described in RFC2255).

URI::LDAPS

The default port for LDAPS URIs is 636, and the scheme is ‘ldaps:’ rather than ‘ldap:’. Other than that, LDAPS URIs are identical to LDAP URIs; see URI::LDAP.

Ractor::IsolationError

No documentation available

RubyVM::AbstractSyntaxTree

AbstractSyntaxTree provides methods to parse Ruby code into abstract syntax trees. The nodes in the tree are instances of RubyVM::AbstractSyntaxTree::Node.

This module is MRI specific as it exposes implementation details of the MRI abstract syntax tree.

This module is experimental and its API is not stable, therefore it might change without notice. As examples, the order of children nodes is not guaranteed, the number of children nodes might change, there is no way to access children nodes by name, etc.

If you are looking for a stable API or an API working under multiple Ruby implementations, consider using the parser gem or Ripper. If you would like to make RubyVM::AbstractSyntaxTree stable, please join the discussion at bugs.ruby-lang.org/issues/14844.

File::Constants

Module File::Constants defines file-related constants.

There are two families of constants here:

Those having to do with file access.
Those having to do with filename globbing.

File constants defined for the local process may be retrieved with method File::Constants.constants:

File::Constants.constants.take(5)
# => [:RDONLY, :WRONLY, :RDWR, :APPEND, :CREAT]

File Access

File-access constants may be used with optional argument mode in calls to the following methods:

Read/Write Access

Read-write access for a stream may be specified by a file-access constant.

The constant may be specified as part of a bitwise OR of other such constants.

Any combination of the constants in this section may be specified.

File::RDONLY

Flag File::RDONLY specifies the stream should be opened for reading only:

filepath = '/tmp/t.tmp'
f = File.new(filepath, File::RDONLY)
f.write('Foo') # Raises IOError (not opened for writing).

File::WRONLY

Flag File::WRONLY specifies that the stream should be opened for writing only:

f = File.new(filepath, File::WRONLY)
f.read # Raises IOError (not opened for reading).

File::RDWR

Flag File::RDWR specifies that the stream should be opened for both reading and writing:

f = File.new(filepath, File::RDWR)
f.write('Foo') # => 3
f.rewind       # => 0
f.read         # => "Foo"

File Positioning

File::APPEND

Flag File::APPEND specifies that the stream should be opened in append mode.

Before each write operation, the position is set to end-of-stream. The modification of the position and the following write operation are performed as a single atomic step.

File::TRUNC

Flag File::TRUNC specifies that the stream should be truncated at its beginning. If the file exists and is successfully opened for writing, it is to be truncated to position zero; its ctime and mtime are updated.

There is no effect on a FIFO special file or a terminal device. The effect on other file types is implementation-defined. The result of using File::TRUNC with File::RDONLY is undefined.

Creating and Preserving

File::CREAT

Flag File::CREAT specifies that the stream should be created if it does not already exist.

If the file exists:

- Raise an exception if File::EXCL is also specified.
- Otherwise, do nothing.

If the file does not exist, then it is created. Upon successful completion, the atime, ctime, and mtime of the file are updated, and the ctime and mtime of the parent directory are updated.

File::EXCL

Flag File::EXCL specifies that the stream should not already exist; If flags File::CREAT and File::EXCL are both specified and the stream already exists, an exception is raised.

The check for the existence and creation of the file is performed as an atomic operation.

If both File::EXCL and File::CREAT are specified and the path names a symbolic link, an exception is raised regardless of the contents of the symbolic link.

If File::EXCL is specified and File::CREAT is not specified, the result is undefined.

POSIX File Constants

Some file-access constants are defined only on POSIX-compliant systems; those are:

File::SYNC.
File::DSYNC.
File::RSYNC.
File::DIRECT.
File::NOATIME.
File::NOCTTY.
File::NOFOLLOW.
File::TMPFILE.

File::SYNC, File::RSYNC, and File::DSYNC

Flag File::SYNC, File::RSYNC, or File::DSYNC specifies synchronization of I/O operations with the underlying file system.

These flags are valid only for POSIX-compliant systems.

File::SYNC specifies that all write operations (both data and metadata) are immediately to be flushed to the underlying storage device. This means that the data is written to the storage device, and the file’s metadata (e.g., file size, timestamps, permissions) are also synchronized. This guarantees that data is safely stored on the storage medium before returning control to the calling program. This flag can have a significant impact on performance since it requires synchronous writes, which can be slower compared to asynchronous writes.
File::RSYNC specifies that any read operations on the file will not return until all outstanding write operations (those that have been issued but not completed) are also synchronized. This is useful when you want to read the most up-to-date data, which may still be in the process of being written.
File::DSYNC specifies that all data write operations are immediately to be flushed to the underlying storage device; this differs from File::SYNC, which requires that metadata also be synchronized.

Note that the behavior of these flags may vary slightly depending on the operating system and filesystem being used. Additionally, using these flags can have an impact on performance due to the synchronous nature of the I/O operations, so they should be used judiciously, especially in performance-critical applications.

File::NOCTTY

Flag File::NOCTTY specifies that if the stream is a terminal device, that device does not become the controlling terminal for the process.