Class: Bridgetown::Webp::WebpExec

Inherits:
Object
  • Object
show all
Defined in:
lib/bridgetown-webp/webpExec.rb

Class Method Summary collapse

Class Method Details

.exe_name ⇒ Object

Returns the correct executable name depending on the OS platform and OS architecture



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# File 'lib/bridgetown-webp/webpExec.rb', line 55

def self.exe_name
  if OS.mac?
    return "osx-cwebp"
  elsif OS.windows?
    if OS.x32?
      return "win-x86-cwebp.exe"
    else
      return "win-x64-cwebp.exe"
    end
  elsif OS.unix? || OS.linux?
    if OS.x32?
      return "linux-x86-cwebp"
    else
      return "linux-x64-cwebp"
    end
  else
    raise ArgumentError.new("OS platform could not be identified (gem can only be run on linux,osx or windows)")
  end
end

.run(quality, flags, input_file, output_file) ⇒ Object

Runs the WebP executable for the given input parameters the function detects the OS platform and architecture automatically



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# File 'lib/bridgetown-webp/webpExec.rb', line 12

def self.run(quality, flags, input_file, output_file)

  # What is the path to the execs inside the gem? perhaps just bin/?
  bin_path = "bin/"

  # What is the OS and architecture specific executable name?
  exe_name = WebpExec.exe_name

  # We need to locate the Gems bin path as we're currently running inside the 
  # bridgetown site working directory
  # http://stackoverflow.com/a/10083594/779521
  gem_spec = Gem::Specification.find_by_name("bridgetown-webp")
  gem_root = gem_spec.gem_dir

  # Construct the full path to the executable
  full_path = File.join(gem_root, bin_path, exe_name)

  # Construct the full program call
  cmd = "\"#{full_path}\" -quiet -mt -q #{quality.to_s} #{flags} \"#{input_file}\" -o \"#{output_file}\""
  
  # Execute the command
  exit_code = 0
  error = ""
  output = ""
  Open3.popen3(cmd) do |stdin, stdout, stderr, wait_thr|
    stdin.close # we don't pass any input to the process
    output = stdout.gets
    error = stderr.gets
    exit_code = wait_thr.value
  end

  if exit_code != 0
    Bridgetown.logger.error("WebP:","Conversion for image #{input_file} failed, no webp version could be created for this image")
    Bridgetown.logger.debug("WebP:","cwebp returned #{exit_code} with error #{error}")
  end

  # Return any captured return value
  return [output, error]
end