Google OAuth

google oauth

var request = require('request');
var events = require('events');
var url = require('url');
var path = require('path');
var crypto = require('crypto');

module.exports = function(opts) {
    if (!opts.callbackURI) opts.callbackURI = 'google/callback';
    if (!opts.loginURI) opts.loginURI = '/google/login';
    if (!opts.scope) opts.scope = 'email';
    var state = crypto.randomBytes(8).toString('hex');
    var urlObj = url.parse(opts.baseURL);
    urlObj.pathname = path.join(urlObj.pathname, opts.callbackURI);
    var redirectURI = url.format(urlObj);
    var emitter = new events.EventEmitter();

    function login(req, resp) {
        var u = 'https://accounts.google.com/o/oauth2/auth?'
            + '&response_type=code'
            + '&client_id=' + opts.googleClient
            + '&redirect_uri=' + redirectURI
            + '&scope=' + opts.scope
            + '&approval_prompt=force&access_type=offline';
        resp.statusCode = 302;
        resp.setHeader('location', u);
        resp.end();
    }

    function callback(req, resp) {
        var query = url.parse(req.url, true).query;
        var code = query.code;
        if (!code) return emitter.emit('error', {error: 'missing oauth code'}, resp);

        request.post('https://accounts.google.com/o/oauth2/token?code=' + code, { form: {
            client_id: opts.googleClient,
            client_secret: opts.googleSecret,
            scope: '',
            redirect_uri: redirectURI,
            grant_type: 'authorization_code'
        }}, function(err, tokenResp, body) {
            if (err) return emitter.emit('error', body, err, resp, tokenResp);
            emitter.emit('token', body, resp, tokenResp);
        });
    }

    emitter.login = login;
    emitter.callback = callback;
    // emitter.addRoutes = addRoutes;
    return emitter;
}