Class: ZplRenderer::Engine

Inherits:
Object
  • Object
show all
Defined in:
lib/zpl_renderer/engine.rb

Overview

Invokes the offline Rust renderer binary over stdin/stdout.

Constant Summary collapse

PROTOCOL_VERSION = 
1

Instance Method Summary collapse

Constructor Details

#initialize(binary_path: nil) ⇒ Engine

Returns a new instance of Engine.



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# File 'lib/zpl_renderer/engine.rb', line 12

def initialize(binary_path: nil)
  @binary_path = binary_path
end

Instance Method Details

#render(zpl, options) ⇒ Object 



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# File 'lib/zpl_renderer/engine.rb', line 16

def render(zpl, options)
  request = JSON.generate(
    protocol: PROTOCOL_VERSION,
    zpl: zpl.to_s,
    format: options.format.to_s,
    width_mm: options.width_mm,
    height_mm: options.height_mm,
    dpmm: options.dpmm,
    index: options.index
  )

  stdout = +"".b
  stderr = +"".b
  status = nil

  begin
    Timeout.timeout(options.timeout) do
      Open3.popen3(binary_path, "--json") do |stdin, out, err, wait_thr|
        stdin.binmode
        out.binmode
        err.binmode

        stdin.write(request)
        stdin.close

        stdout = out.read
        stderr = err.read
        status = wait_thr.value
      end
    end
  rescue Timeout::Error
    raise TimeoutError, "render timed out after #{options.timeout}s"
  rescue Errno::ENOENT
    raise BinaryMissingError, Binary.missing_message
  end

  unless status&.success?
    message = stderr.to_s.strip
    message = "renderer exited with status #{status&.exitstatus}" if message.empty?
    raise_for_message!(message)
  end

  if stdout.bytesize > options.max_output_bytes
    raise OutputTooLargeError,
          "output is #{stdout.bytesize} bytes; max_output_bytes=#{options.max_output_bytes}"
  end

  stdout
end