CharlockHolmes
Character encoding detecting library for Ruby using ICU
Usage
First you'll need to require it
require 'charlock_holmes'
Encoding detection
contents = File.read('test.xml')
detection = CharlockHolmes::EncodingDetector.detect(contents)
# => {:encoding => 'UTF-8', :confidence => 100, :type => :text}
# optionally there will be a :language key as well, but
# that's mostly only returned for legacy encodings like ISO-8859-1
NOTE: CharlockHolmes::EncodingDetector.detect
will return nil
if it was unable to find an encoding.
For binary content, :type
will be set to :binary
Though it's more efficient to reuse once detector instance:
detector = CharlockHolmes::EncodingDetector.new
detection1 = detector.detect(File.read('test.xml'))
detection2 = detector.detect(File.read('test2.json'))
# and so on...
String monkey patch
Alternatively, you can just use the detect_encoding
method on the String
class
require 'charlock_holmes/string'
contents = File.read('test.xml')
detection = contents.detect_encoding
Ruby 1.9 specific
NOTE: This method only exists on Ruby 1.9+
If you want to use this library to detect and set the encoding flag on strings, you can use the detect_encoding!
method on the String
class
require 'charlock_holmes/string'
contents = File.read('test.xml')
# this will detect and set the encoding of `contents`, then return self
contents.detect_encoding!
Transcoding
Being able to detect the encoding of some arbitrary content is nice, but what you probably want is to be able to transcode that content into an encoding your application is using.
content = File.read('test2.txt')
detection = CharlockHolmes::EncodingDetector.detect(content)
utf8_encoded_content = CharlockHolmes::Converter.convert content, detection[:encoding], 'UTF-8'
The first parameter is the content to transcode, the second is the source encoding (the encoding the content is assumed to be in), and the third parameter is the destination encoding.
Installing
If the traditional gem install charlock_holmes
doesn't work, you may need to specify the path to
your installation of ICU using the --with-icu-dir
option during the gem install or by configuring Bundler to
pass those arguments to Gem:
Configure Bundler to always use the correct arguments when installing:
bundle config build.charlock_holmes --with-icu-dir=/path/to/installed/icu4c
Using Gem to install directly without Bundler:
gem install charlock_holmes -- --with-icu-dir=/path/to/installed/icu4c
If you get a compile time error that looks like error: delegating constructors are permitted only in C++11
or something else related to C++11, you need to set the --with-cxxflags=-std=c++11
options
Bundler:
bundle config build.charlock_holmes --with-icu-dir=/path/to/installed/icu4c --with-cxxflags=-std=c++11
Installing directly:
gem install charlock_holmes -- --with-icu-dir=/path/to/installed/icu4c --with-cxxflags=-std=c++11
Homebrew
If you're installing on Mac OS X then using Homebrew is the easiest way to install ICU.
However, be warned; it is a Keg-Only (see homedir issue #167
for more info) install meaning RubyGems won't find it when installing without specifying --with-icu-dir
To install ICU with Homebrew:
brew install icu4c
Configure Bundler to always use the correct arguments when installing:
bundle config build.charlock_holmes --with-icu-dir=/usr/local/opt/icu4c
Using Gem to install directly without Bundler:
gem install charlock_holmes -- --with-icu-dir=/usr/local/opt/icu4c