talktrans - server side

app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/translate', routes);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});


module.exports = app;

app.listen(8888);

routes_index.js

var url = require('url');
var express = require('express');
var translator = require('../translate');
var router = express.Router();

router.get('/', function(req, res, next) {
    res.render('index', { title: "talktrans"});
});

router.get('/translate', function(req, res, next) {
    var urlParts = url.parse(req.url, true);
    var queries = urlParts.query;

    if (queries && queries.text) {
        translator.getAccessToken(function (token) {
            translator.translate(token, queries.text, function (translated, from, to) {
                res.json({
                    translated: translated,
                    from: from,
                    to: to
                });
            });
        });
    } else {
        res.status(404).send("a query parameter 'text' was not found.")
    }
});

module.exports = router;

translate.js

'use strict';

var http = require('http');
var https = require('https');
var request = require('request');
var qs = require('querystring');

var MS_TRANSLATOR_SCOPE            = "http://api.microsofttranslator.com";
var MS_TRANSLATOR_ACCESSTOKEN_URL  = "https://datamarket.accesscontrol.windows.net/v2/OAuth2-13";
var MS_TRANSLATOR_URL              = "http://api.microsofttranslator.com/V2/Http.svc/Translate";
var MS_TRANSLATOR_GRANT_TYPE       = "client_credentials";

function getAccessToken(callback) {
    var data = {
        'client_id': 'your-client-id',
        'client_secret': 'your-client-secret',
        'scope': MS_TRANSLATOR_SCOPE,
        'grant_type': MS_TRANSLATOR_GRANT_TYPE
    };
    var options = {
        url: MS_TRANSLATOR_ACCESSTOKEN_URL,
        method: "POST",
        form: data
    };
    request(options, function(error, response, body) {
        var resData = JSON.parse(body);
        callback(resData.access_token);
    });
}

function translate(token, text, callback) {
    var headers = {
        Authorization: "Bearer " + token
    };

    var from, to;
    if (isJapanese(text)) {
        from = "ja";
        to = "en";
    } else {
        from = "en";
        to = "ja";
    }

    var data = {
        text: text,
        from: from,
        to: to
    };
    var options = {
        url: MS_TRANSLATOR_URL + "?" + qs.stringify(data),
        method: "GET",
        headers: headers,
        form: data
    };
    request(options, function(error, response, body) {
        var xmlparser = require('xml2js').parseString;
        xmlparser(body, function (err, result) {
            if (result && result.string && result.string._) {
                callback(result.string._, from, to);
            }
        });
    });
}

function isJapanese(txt) {
    if (typeof txt !== "string") {
        return false;
    }

    var i = txt.length, escapeTxt;

    while(i--) {
        escapeTxt = escape(txt.substring(i, i + 1));
        if (escapeTxt.length >= 6) {
            return true;
        }
    }

    return false;
}

exports.getAccessToken = getAccessToken;
exports.translate = translate;