an example application of a Jeopardy question API with Loopback and MongoDB
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README.md

Jeopardy API with LoopBack and MongoDB

Set up an easy API with LoopBack, MongoDB, and IBM's Bluemix.

You will need:

Local Development
  1. Node (version 6.6 or higher)
  2. NPM (version 3.10 or higher)
  3. LoopBack cli npm install -g loopback-cli
  4. MongoDB (3.4: installation instructions here)
Bluemix Deployment
  1. Bluemix Account (sign up here)
  2. Bluemix CLI (download and installation instructions here)
Data

The Jeopardy! dataset (216,930 Jeopardy! questions in JSON format) is available here. Thanks so much to the great Data is Plural tinyletter for finding and sharing so many interesting datasets!

  • Hint: If you want to do date search in Mongo with this dataset, you will need to convert the dates to a Date format. You can do this once your data has been loaded in Mongo with a shell command like this: db.jeopardy.find().forEach(function(doc){doc.air_date = new ISODate(doc.air_date);db.jeopardy.save(doc)})

Create Your API

Start Mongo

Start Mongo locally and load your data into your local MongoDB. (Your process will vary, but you could use something like mongoimport --db test --collection jeopardy --file JEOPARDY_QUESTIONS.txt

Time for LoopBack!

To create your LoopBack application, use lb app jeopardy-mongo-api

Loopback init

Loopback app creation

Wait for npm install to finish, then cd jeopardy-mongo-api

Add your datasource!

lb datasource

Name your datasource and choose the LoopBack MongoDB connector:

Loopback datasource 2

If you use a URL for your connector you don't need to specify the host/port/user/password:

Loopback datasource 2

Wait for npm install of the connector to finish.

Create your model!

lb model

The schema for the Jeopardy! questions is

	"_id" : ObjectId("5922063e8f51a16a884263bf"),
	"category" : "HISTORY",
	"air_date" : "2004-12-31",
	"question" : "'For the last 8 years of his life, Galileo was under house arrest for espousing this man's theory'",
	"value" : "$200",
	"answer" : "Copernicus",
	"round" : "Jeopardy!",
	"show_number" : "4680"
}

Name your model and connect it to the datasource you just created. You probably won't be saving new questions to the database but you can just go ahead and select PersistedModel just in case: LoopBack model

Expose your model through the API and make it 'common' (available to both the server and client). We're only creating a server in this example but there's no harm in choosing 'common'.

LoopBack model

You don't need to create a property specifically for '_id'; LoopBack will do it for you:

LoopBack model

Start your API!

node .

LoopBack start

Check out the Explorer!

LoopBack explorer

...

LoopBack explorer 2

...

LoopBack explorer 3

Create custom endpoints

A. Get a random question:

In the common/models/jeopardy-question.js file, add the endpoint functionality:

Jeopardyquestion.random = function(cb){
	Jeopardyquestion.getDataSource().connector.connect(function(err, db) {
		  var collection = db.collection('jeopardyQuestion');
		  collection.aggregate([
		    { $sample: { size: 1 } }
		  ], function(err, data) {
		    if (err) return cb(err);
		    return cb(null, data);
		  });
		});
	}

and the endpoint description:

	Jeopardyquestion.remoteMethod(
		'random', {
			http: {
				path: '/random',
				verb: 'get'
			},
			description: 'Gets one random question',
			returns: {
				arg: 'questions',
				type: 'json'
			}
		});

B. Get the entire list of Jeopardy! categories:

In the common/models/jeopardy-question.js file, add the endpoint functionality:

Jeopardyquestion.categories = function(cb){
		Jeopardyquestion.getDataSource().connector.connect(function(err, db) {
		  var collection = db.collection('jeopardyQuestion');
		  collection.distinct('category', function(err, data) {
		    if (err) return cb(err);
		    return cb(null, data);
		  });
		});
	}

and the endpoint description:

	Jeopardyquestion.remoteMethod(
		'categories', {
			http: {
				path: '/categories',
				verb: 'get'
			},
			description: 'Gets list of categories',
			returns: {
				arg: 'categories',
				type: 'json'
			}
		});

Restart your application, and you should now see these endpoints in your Explorer:

LoopBack remote method LoopBack remote method

Deploy to Bluemix
  1. Sign in to Bluemix
  2. In the Bluemix Catalog, choose the LoopBack Starter App
  3. Download the starter code that they give you: LoopBack starter
  4. Open the manifest.yml file in your downloaded starter code and copy that file to your LoopBack application. manifest.yml
  5. Provision and connect a Compose for MongoDB on Bluemix Compose for MongoDB
  6. Get your Compose MongoDB credentials: credentials1 credentials1
  7. With those credentials you can set two environment variables for your application: MONGODB_CONNECTION_URL and ca_certificate_base64 cf set-env $YOUR_APP_NAME MONGODB_CONNECTION_URL $YOUR_MONGO_URI cf set-env $YOUR_APP_NAME ca_certificate_base64 $YOUR_CA_CERTIFICATE (Replace the $YOUR_APP_NAME and $YOUR_MONGO_URI and $YOUR_CA_CERTIFICATE` with your Bluemix app name, your "ca_certificate_base64" the "uri" values from your credentials.
  8. Add a server/datasources.production.json file, with this content:
{
  "mongo":{
    "name": "mongo",
    "url": "${MONGODB_CONNECTION_URL}",
    "connector":"mongodb",
    "ssl":true,
    "server": {
        "auto_reconnect": true,
        "reconnectTries": 100,
        "reconnectInterval": 1000,
        "sslValidate":false,
        "checkServerIdentity":false,
        "sslCA":"${ca_certificate_base64}"
    } 
  }
}
  1. Add a node engines property json "engines": { "node": ">=6.9.1" }, and "cfenv": "1.0.x", to your dependencies in your package.json.
  2. Push your app: cf push $YOUR_APP_NAME
  3. You should now see your app at $YOUR_APP\NAME.mybluemix.net/explorer!

NOTE: at this point you won't have any data in the Compose for MongoDB instance that is attached to your Bluemix LoopBack app. You can load data into your Compose for MongoDB in a couple of different ways. One quick way is to do a mongodump from your local MongoDB, and then mongorestore it to your Compose for MongoDB instance, like so: mongorestore --ssl --sslAllowInvalidCertificates --host $YOUR_COMPOSE_HOST --db admin --collection jeopardyQuestion -u $YOUR_COMPOSE_USERNAME -p $YOUR_COMPOSE_PASSWORD jeopardyQuestion.bson