Module: Helpema::Piper

Included in:
FFMPEG, GPG, Rubish, SSSS, YouTubeDL, ZBar
Defined in:
lib/helpema/piper.rb

Defined Under Namespace

Modules: Refinements

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.run_command(cmd, options = {}, script: nil, usage: nil, synonyms: nil, mode: 'r', exception: nil, forward_pass: nil, **popt, &blk) ⇒ Object

Assume caller knows what it’s doing(no dummy proofing here)



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# File 'lib/helpema/piper.rb', line 78

def Piper.run_command(cmd, options={}, script:nil,
  usage:nil, synonyms:nil, mode:'r',
  exception:nil, forward_pass:nil, **popt, &blk)
  args,ret = options.to_args(usage:usage,synonyms:synonyms),nil
  $stderr.puts "#{cmd} #{args.join(' ')}" if $DEBUG
  IO.popen([cmd, *args], mode, **popt) do |pipe|
    pipe.write script if script
    if forward_pass
      ret = forward_pass.call(pipe, options, blk)
    elsif blk
      ret = blk.call(pipe, options)
    elsif mode=='r'
      ret = pipe.read
    elsif mode=='w+'
      pipe.close_write
      ret = pipe.read
    end
  end
  # False exception instead of nil or "an error message"
  # flags the expected behavior as defined:
  success = ($?.exitstatus==0)
  raise(exception) if exception and not success
  return success if exception==false
  return ret
end

.to_arg(key, value) ⇒ Object 



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# File 'lib/helpema/piper.rb', line 63

def Piper.to_arg(key,value)
  # keep only keys with value(no false or nil)
  return nil unless value
  # assume nil0/--long/-short
  key = key.to_flag
  if key
    return key if value==true # a flag
    return "#{key}#{value}" if key[-1]=='=' # joined key=value
    return [key,value.to_s]
  end
  # It's a Nth arg, like arg0...
  return value.to_s
end

.validate_command(cmd, version, flag = '--version') ⇒ Object 



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# File 'lib/helpema/piper.rb', line 34

def Piper.validate_command(cmd, version, flag='--version')
  raise "`#{cmd} #{flag}` !~ #{version}" unless
  `#{cmd} #{flag}`.strip.match?(version)
end

Instance Method Details

#define_command(name, cmd: name.to_s.chomp('?').chomp('!'), version: nil, v: nil, usage: nil, synonyms: nil, mode: 'r', exception: nil, default: nil, **popt, &forward_pass) ⇒ Object

Note: popt is IO.popen’s options(think of it as “pipe’s options”).



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# File 'lib/helpema/piper.rb', line 40

def define_command(name,
                   cmd:name.to_s.chomp('?').chomp('!'),
                   version:nil, v:nil,
                   usage:nil,   synonyms:nil,
                   mode:'r',    exception:nil, default:nil,
                   **popt,      &forward_pass)
  raise "bad name or cmd" unless name=~/^\w+[?!]?$/ and cmd=~/^[\w.\-]+$/
  Piper.validate_command(cmd, version) if version
  Piper.validate_command(cmd, v, '-v') if v
  define_method(name) do |script=default, **options, &blk|
    if mode[0]=='w'
      raise 'need script to write' unless script or blk or forward_pass
    else
      raise 'cannot write script' if script
    end
    Piper.run_command(cmd, options, script:script,
      usage:usage, synonyms:synonyms, mode:mode,
      exception:exception, forward_pass:forward_pass, **popt, &blk)
  end
end