API.md

Using Reek inside your Ruby application

Installation

Either standalone via

gem install reek

or by adding

gem 'reek'

to your Gemfile.

Quick start

Code says more than a thousand words:

require 'reek'

source = <<-EOS
  class Dirty
    def m(a,b,c)
      puts a,b
    end
  end
EOS

reporter = Reek::Report::TextReport.new
examiner = Reek::Examiner.new source
reporter.add_examiner examiner
reporter.show

This would output the following on STDOUT:

string -- 5 warnings:
  Dirty has no descriptive comment (IrresponsibleModule)
  Dirty#m has the name 'm' (UncommunicativeMethodName)
  Dirty#m has the parameter name 'a' (UncommunicativeParameterName)
  Dirty#m has the parameter name 'b' (UncommunicativeParameterName)
  Dirty#m has unused parameter 'c' (UnusedParameters)

Note that Reek::Examiner.new can take source as String, Pathname, File or IO.

API stability

Everything that is mentioned in this document can be considered stable in the sense that it will only change across major versions.

There is one thing in this API documentation you can't and shouldn't rely on: The SmellWarning messages itself.

Something like this

Dirty#m has the parameter name 'a' (UncommunicativeParameterName)

might change even across minor versions.

You should not need to be specific about those messages anyways. In case you'd like to be specific about SmellWarnings please have a look at accessing the smell warnings directly.

Additionally you can use one of our structured outputs formats like JSON or YAML if you need a more fine-grained access to our SmellWarnings.

Choosing your output format

Besides normal text output, Reek can generate output in YAML, JSON, HTML and XML by using the following Report types:

TextReport
YAMLReport
JSONReport
HTMLReport
XMLReport

Configuration

Given you have the following configuration file called .reek.yml in your root directory:

---
IrresponsibleModule:
  enabled: false

Reek will load this file automatically by default. If you want to load the configuration explicitely, you can use one of the methods below.

You can now use either

Reek::Configuration::AppConfiguration.from_path Pathname.new('config.reek')

but you can also pass a hash with the contents of the .reek.yml YAML file to Reek::Configuration::AppConfiguration.from_hash.

Given the example above you would load that as follows:

require 'reek'

config_hash = { 'IrresponsibleModule' => { 'enabled' => false } }
configuration = Reek::Configuration::AppConfiguration.from_hash config_hash

source = <<-EOS
  class Dirty
    def call_me(a,b)
      puts a,b
    end
  end
EOS

reporter = Reek::Report::TextReport.new
examiner = Reek::Examiner.new(source, configuration: configuration); nil
reporter.add_examiner examiner; nil
reporter.show

This would now only report UncommunicativeParameterName but not IrresponsibleModule for the Dirty class:

string -- 2 warnings:
  Dirty#call_me has the parameter name 'a' (UncommunicativeParameterName)
  Dirty#call_me has the parameter name 'b' (UncommunicativeParameterName)

Of course, directory specific configuration and excluded paths are supported as well:

config_hash = {
  'IrresponsibleModule' => { 'enabled' => false }
  'spec/samples/three_clean_files/' =>
    { 'UtilityFunction' => { "enabled" => false } }
  'exclude_paths' =>
    [ 'spec/samples/two_smelly_files' ]
}

Accessing the smell warnings directly

You can also access the smells detected by an examiner directly:

require 'reek'

source = <<-END
  class C
  end
END

examiner = Reek::Examiner.new source
examiner.smells.each do |smell|
  puts smell.message
end

Examiner#smells returns a list of SmellWarning objects.