mosesdecoder/contrib/goshen-chrome/README.md

goshen

Goshen is a Chrome extension that duplicates the utility of the Google Translate chrome extension for on-page website translation, using the Goshen JavaScript library with Moses as a backend translator. (It also has the ability to swap in an arbitrary translation engine, if the appropriate adapters are written.)

1. The Goshen.js Library

As Google Translate is the current go-to machine-translation system for developers, I intend to make Moses a viable alternative for even the non-savvy developer. This is in large part simplified by having an easily deployed (perhaps Dockerized) Moses server, as mentioned in the section above. However, it is also greatly simplified by exposing a comprehensive and well-formed JavaScript API that allows the same level of flexibility as the existing Google API.

Instead of trying to duplicate the Google Translate API, I instead chose to write a wrapper for any translation engine. An engine with an exposed HTTP endpoint can be added to the Goshen translation library by implementing GoshenAdapter, for which I have provided a complete moses-mt-server implementation (MosesGoshenAdapter) and a partially complete proof of concept for Google Translate (GoogleTranslateGoshenAdapter). This is to illustrate that the engines can be used interchangeably for simple translation tasks, but the entirety of Moses functionality can be accessed whereas Google Translate's public API fails to accommodate some more technical tasks.

The library is both commented and minified, available in the goshenlib/ directory, here. It is also possible to import the unminified, importable version from goshenlib/dist. The complete documentation, as well as usage examples and implementation explanations and justifications, are available in goshenlib/docs at the above repository.

2. Chrome Extension

This directory contains a Chrome extension that utilizes the CASMACAT moses-mt-server/Moses backend to provide a frontend website translation service. The extension automatically detects the relevant content of most articles or body-text on the page, and at the user's request, translates it to the requested language. Usage is explained below, as well as inside the extension popup after installation, for quick reference.

Usage

1. Install the unpacked extension. Go to chrome://extensions and click Load Unpacked Extension. Navigate to this goshen-chrome/ directory, and load.
2. This adds a Goshen icon to your Chrome toolbar. Clicking it brings up a simple modal that allows the switching of languages.
3. Use the Alt+T key-chord ("T" for "Translate") to begin text-selection. The Goshen-translate extension will highlight elements of text in cyan as you mouse over them: To translate what is currently highlighted, click.

Goshen.js Documentatio

Overview

The Goshen library provides a web-developer-facing library for handling machine translation. It allows interaction with arbitrary machine translation services, agnostic of the technology or algorithm stack.

Usage

A very brief tutorial is provided here:

• Create a new Goshen object. Use the MosesGoshenAdapter, so that translations are handled by a Moses MT server.

  g = new Goshen('localhost:3000', 'http', MosesGoshenAdapter);
  

• Use the Goshen object to pass a translation job to the Moses adapter. The adapter will pass back a completed translation once the job completes.

  g.translate('This is a simple sentence.', Languages.ENGLISH, Languages.SPANISH);
  

• You can also optionally pass a callback function to the .translate method:

  g.translate('This is a simple sentence.',
              Languages.ENGLISH,
              Languages.SPANISH,
              function(err, val) {
      if (!!err) {
          console.warn("Encountered an error: " + err);
      } else {
          console.info("Translated to: " + val);
      }
  });
  

  If a callback is supplied, the function is run on a new thread, and is non-blocking. If one is not supplied, then the return value of the function contains the translated text. undefined is returned if the translation fails.

Goshen

The generic class for a Goshen.js object, the object that handles translation with an arbitrary translation backend. In order to specify a backend, pass a type parameter to the constructor. (Default is Moses, of course!)

• Goshen

  • Arguments:
    • hostname: A string hostname, such as locahost:8000. This is the base URL for formulating the RESTful API endpoint.
    • protocol: The HTTP protocol. Either http or https.
    • type: What type of GoshenAdapter to use. Options are currently GoogleTranslateGoshenAdapter or MosesGoshenAdapter.
    • opts: A dictonary of options to pass to the adapter constructor. Currently, none are required for existing adapters.

• function url

  Generate a complete URI. If hostname is localhost:8000 and protocol is https, then this.url('foo') returns https://localhost:8000/foo

  • Arguments:
    • suffix: A suffix to concatenate onto the end of a well-formed URI.
  • Returns:
    • String: The complete web-accessible URL.

• function translate

  Translate a text from a source language to a target language.

  • Arguments:
    • text: The text to translate. If this is too long, a series of truncated versions are translated, splitting on sentence-delimiters if possible.
    • source: An item from the LANGUAGES set (e.g. 'en-us')
    • target: An item from the LANGUAGES set (e.g. 'en-us')
    • callback: Optional. If supplied, must be a function (or be of a callable type) that will be run with errors and value as its two arguments.
  • Returns:
    • String: The translated text. All supplementary data, such as alignments or language detections, are ignored by this function.

GoshenAdapter

The Goshen class secretly outsources all of its computation to a GoshenAdapter class attribute, which is responsible for performing the machine translation. GoshenAdapters should expose url and translate functions unambiguously, with the same signatures as those in the Goshen class. Other functions may be optionally exposed.

MosesGoshenAdapter

This is one particular implementation of the GoshenAdapter type, that uses the moses-mt-server backend as its translation engine API endpoint. It splits text into manageable chunks when translating, to avoid crashing the underlying Moses server (RAM allocation fail).

GoogleTranslateGoshenAdapter

This is another implementation of the GoshenAdapter type, that uses the Google Translate API as its translation engine endpoint. Because Google handles arbitrarily long text, this adapter does not split text, as MosesGoshenAdapters do.

For more information, see this full report, or contact Jordan Matelsky (@j6k4m8).