class AbstractCommand

Shell Command Abstraction.

Hides away all the details to generate a command. And privides an easy interface to interact with shell commands as if they were objects.

This is good for the following reasons:

Stadardization.
Simplicity of code.
Reduces smells in methods that interpolate values.
Provides an elegant way to interact shell objects.
Secure ensures that shell commands are executed safely.

Constants

VARIABLE_REGEX: '%<name>s'.scan(/(%<)(w+)(>)/)

> [[“%<”, “name”, “>”]]¶ ↑

Public Class Methods

new(properties = {}) click to toggle source

# File lib/abstract_command.rb, line 35
def initialize(properties = {})
  variables.each do |variable|
    self.class.send(:attr_accessor, variable.to_sym)
  end
  properties.each do |key, value|
    setter = (key.to_s + '=').to_sym
    send(setter, value)
  end
end

Public Instance Methods

backtick() click to toggle source

# File lib/abstract_command.rb, line 58
def backtick
  `#{to_s}`
end

execute() click to toggle source

# File lib/abstract_command.rb, line 62
def execute
  begin
    stdout, stderr, status = Open3.capture3(to_s)
    status = status.exitstatus
  rescue StandardError => error
    stdout = ""
    if(error.message)
      stderr = error.message
    end
    status = 1
  end
  return stdout, stderr, status
end

system() click to toggle source

Calls superclass method

# File lib/abstract_command.rb, line 54
def system
  super(to_s)
end

template() click to toggle source

# File lib/abstract_command.rb, line 23
def template
  raise 'must implement'
end

to_s() click to toggle source

# File lib/abstract_command.rb, line 45
def to_s
  bindings = {}
  variables.each do |variable|
    value = instance_variable_get("@#{variable}")
    bindings[variable.to_sym] = "#{value}".shellescape
  end
  format(template, bindings)
end

variables() click to toggle source

# File lib/abstract_command.rb, line 27
def variables
  result = []
  template.scan(VARIABLE_REGEX).each do |variable|
    result.push(variable[1])
  end
  result
end

class AbstractCommand

> [[“%<”, “name”, “>”]]¶ ↑