app.js

/**
 * Copyright 2015 IBM Corp. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';

var express = require('express'),
  app = express(),
  pkg = require('./package.json'),
  Q = require('q'),
  fs = require('fs'),
  watson = require('watson-developer-cloud');

// Bootstrap application settings
require('./config/express')(app);

var log = console.log.bind(null, '  ');
var conversation;
var discovery;
var serviceCredentials;
var intentConfidence;

var allowCrossDomain = function (req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
  res.header('Access-Control-Allow-Headers', 'Content-Type');

  next();
};

app.use(allowCrossDomain);

// set credentials from bluemix or local .env file
if (process.env.VCAP_SERVICES) {
  console.log("setting vcap services");
  var services = JSON.parse(process.env.VCAP_SERVICES);

  serviceCredentials = null;

  conversation = new watson.ConversationV1({
    url: services.conversation[0].credentials.url || 'https://gateway.watsonplatform.net/conversation/api',
    username: services.conversation[0].credentials.username || '<username>',
    password: services.conversation[0].credentials.password || '<password>',
    version_date: process.env.conversation_version,
    version: 'v1'
  });

  discovery = new watson.DiscoveryV1({
    url: services.discovery[0].credentials.url || 'https://gateway.watsonplatform.net/discovery/api',
    username: services.discovery[0].credentials.username || '<username>',
    password: services.discovery[0].credentials.password || '<password>',
    version_date: process.env.discovery_version
  });

  intentConfidence = process.env.intent_confidence;

} else {
  // load the environment variables - for local testing
  if (fs.existsSync('./.env.js')) {
    Object.assign(process.env, require('./.env.js'));
  }

  serviceCredentials = JSON.parse(process.env.VCAP_SERVICES);

  conversation = new watson.ConversationV1({
    url: serviceCredentials.conversation[0].credentials.url || 'https://gateway.watsonplatform.net/conversation/api',
    username: serviceCredentials.conversation[0].credentials.username || '<username>',
    password: serviceCredentials.conversation[0].credentials.password || '<password>',
    version_date: process.env.conversation_version,
    version: 'v1'
  });

  discovery = new watson.DiscoveryV1({
    url: serviceCredentials.discovery[0].credentials.url || 'https://gateway.watsonplatform.net/discovery/api',
    username: serviceCredentials.discovery[0].credentials.username || '<username>',
    password: serviceCredentials.discovery[0].credentials.password || '<password>',
    version_date: process.env.discovery_version
  });

  intentConfidence = .75;
}

// main endpoint
var previousContext = null;
app.post('/api/message', function (req, res) {
  var workspace = process.env.workspace_id;
  if (!workspace) {
    return res.json({
      'output': {
        'text': 'The app has not been configured with a <b>WORKSPACE_ID</b> environment variable. Please refer to the ' +
        '<a href="https://github.com/watson-developer-cloud/conversation-simple">README</a> documentation on how to set this variable. <br>' +
        'Once a workspace has been defined the intents may be imported from ' +
        '<a href="https://github.com/watson-developer-cloud/conversation-simple/blob/master/training/car_workspace.json">here</a> in order to get a working application.'
      }
    });
  }
  var payload = {
    workspace_id: workspace,
    context: {},
    input: {}
  };

  if (req.body) {
    if (req.body.input) {
      payload.input = req.body.input;
    }
    if (req.body.context) {
      // The client must maintain context/state
      payload.context = req.body.context;
    }
  }

  if (!payload.context) {
    payload.context = previousContext;
  }

  (function () {
    var deferred = Q.defer();
    conversation.message(payload, function (err, data) {
      if (err) {
        console.log("ERROR");
        console.log(err);
        return res.status(err.code || 500).json(err);
      }

      deferred.resolve(data);
    })
    return deferred.promise;

  })().then(function (data) {

    if(data.intents.length > 0 && data.intents[0].intent == "subject_filter") {

     // return discovery data
      var response = {
        "input": {"text": req.body.input.text},
        "context": data.context,
        "output": {"text": []}
      };

      var version_date = process.env.discovery_version;
      var environment_id = process.env.environment_id;
      var collection_id = process.env.collection_id;

      discovery.query({
          version_date: version_date,
          environment_id: environment_id,
          collection_id: collection_id,
          query: req.body.input.text,
          count: 10
        },
        (err, data) => {
          if (err) {
            console.log("Error: ");
            console.log(err);
            return res.status(err.code || 500).json(err);
          }

          if (data.results.length > 0) {
            var randomInt = Math.floor(Math.random() * data.results.length/2);
            var firstResult = data.results[randomInt];
            // Find a new article if a field is missing to prevent crash
            while(firstResult.date === undefined || firstResult.title === undefined) {
              randomInt = Math.floor(Math.random() * data.results.length/2);
              firstResult = data.results[randomInt];
            }

            var splitDate = firstResult.date.split('-');
            splitDate[2] = splitDate[2].slice(0, 2);
            var joinedDate = splitDate.join("/");
            var title = firstResult.title.toLowerCase().split(' ').join('_');
            response.output.text.push(`<a href="https://poly.rpi.edu/${joinedDate}/${title}/">` + firstResult.title + "</a>");
          }
          else {
            response.output.text.push("I cannot find an answer to your question.");
          }

          return res.json(response);
        }
      );

    }
    else {

      return res.json(data);

    }
  });
});

// error-handler application settings
require('./config/error-handler')(app);

var port = process.env.PORT || 3000;
//var host = process.env.VCAP_APP_HOST || 'localhost';
app.listen(port);

//console.log(pkg.name + ':' + pkg.version, host + ':' + port);