In previous IBM Mobile Foundation tutorial we demoed the backend connections capability of MFP and the use of MFP Adapters to communicate with Cloundant databases . In this tutorial we will demo IBM Cloudant connections through NodeJS services .

The content in this tutorial is very basic and simple to get you started with IBM Cloudant .

We will start with setting up a new IBM Cloudant service and creating few databases , then writing a server.js to acccess the NoSQL cloudant service  and query or inserts data to its databases . 

Cloudant setup

1. create a cloudant NoSQl DB service through the IBM Cloud dashboard :

   from your  Cloudant service dashboard , click on Launch Cloudant Dashboard:
   
2. populate new service credentials from your new Cloudant instance’s dashboard / Service credentials :
   these credentials will be used as config data in the NodeJS server to access your Cloudant .
   
3. create a new database with the name cities , and a database with the name countries as per our sample code requirements :

we will leave the two databases with no documents for the moment, and pass to perform the insertion through JS code .

NodeJS service to query/insert data

You can clone this repo for the NodeJS service code ! I am sharing the repo’s link first because the code is basic and simple . Still, I recommend you follow these steps before running the sample app .

1. 1. 1. 1. Create service credentials config file (vcap-local.json)
            we will store the service credentials generated in previous steps in vcap-local.json file on this format :

            {
                "services": {
                    "cloudantNoSQLDB": {
                        "credentials":
                             SERVICE CREDENTIALS HERE
                        ,
                        "label": "cloudantNoSQLDB"
                    }
                }
            }

            so your final vcap-local.json will be the following :

            {
                "services": {
                    "cloudantNoSQLDB": {
                        "credentials":{
                        "apikey": "XYZ",
                        "host": "XYZ",
                        "iam_apikey_description": "XYZ",
                        "iam_apikey_name": "XYZ",
                        "iam_role_crn": "XYZ",
                        "iam_serviceid_crn": "XYZ",
                        "password": "XYZ",
                        "port": "XYZ",
                        "url":"XYZ",
                         "username": "XYZ"
                        }            
                        ,
                        "label": "cloudantNoSQLDB"
                    }
                }
            }

         2. Initialize the Cloudant library 
            in order to connect to Cloudant service through NodeJS we will use Cloudant’s official node driver (Cloudant Node.js Client ) . Which we can add to our app using:

            $ npm install --save @cloudant/cloudant
            

            add the following to your server.js file to load the Cloudant library and initialise it with the credentials being parsed from vcap-local.json :

            let vcapLocal;
            try {
                vcapLocal = require('./vcap-local.json');
                console.log("Loaded local VCAP", vcapLocal);
            } catch (e) { 
                console.log("Error loading cloudant credentials file", vcapLocal); 
            }
            
            const appEnvOpts = vcapLocal ? {
                vcap: vcapLocal
            } : {}
            const appEnv = cfenv.getAppEnv(appEnvOpts);
            var Cloudant = require('@cloudant/cloudant');
            
            if (process.env.VCAP_SERVICES) {
                var env = JSON.parse(process.env.VCAP_SERVICES);
                var credentials = env['cloudantNoSQLDB'][0]['credentials'];
                cloudant = new Cloudant({ url: credentials.url, maxAttempt: 25, plugins: { retry: { retryErrors: false, retryStatusCodes: [429] } } });
            } else if (appEnv.services['cloudantNoSQLDB'] || appEnv.getService(/cloudant/)) {
            
                if (appEnv.services['cloudantNoSQLDB']) {
                    cloudant = new Cloudant({ url: appEnv.services['cloudantNoSQLDB'][0].credentials.url, maxAttempt: 25, plugins: { retry: { retryErrors: false, retryStatusCodes: [429] } } });
                } else {
                    cloudant = new Cloudant({ url: appEnv.getService(/cloudant/).credentials.url, maxAttempt: 25, plugins: { retry: { retryErrors: false, retryStatusCodes: [429] } } });
                }
            
            } else if (process.env.CLOUDANT_URL) {
                cloudant = new Cloudant({ url: process.env.CLOUDANT_URL, maxAttempt: 25, plugins: { retry: { retryErrors: false, retryStatusCodes: [429] } } });
            
            

         3. Insert / delete or update data to Cloudant
            –  add a city database entry to your Cities database with a reference to a Countries database document , where country name is given :

            app.post("/api/addCity", cors(), function (request, response) {
                let countryID;
                countries_db = cloudant.db.use("countries");
                cities_db = cloudant.db.use("cities");
                if (!countries_db || !cities_db) {
                    responseError("An error has occured", 400, response);
                    return;
                }
                countries_db.find({
                    selector: {
                        "name": request.body.toCountry
                    }
                }, function (err, result) {
                    if (err) {
                        throw err;
                    }
                    countryID = eval(JSON.stringify(result["docs"]))[0]._id;
                    cities_db.insert({ name: request.body.name, country_id: countryID }, function (err, result) {    
                        if (err) {
                            throw err;
                        }
                        console.log("Current cities list: " + JSON.stringify(result));
                    });
                    var responseJson =
                    {
                        "success": true,
                        "added city": request.body.name,
                        "toCountry": request.body.toCountry
            
                    };
                    response.status(200);
                    response.json(responseJson);
                });
            });

            read all documents in Countries database :

            app.post("/api/getAllCountries", cors(), function (request, response) {
                countries_db = cloudant.db.use("countries");
                if (!countries_db) {
                    responseError("An error has occured", 400, response);
                    return;
                }
                countries_db.find({                                 
                    selector: {
                        "continent": request.body.continent
                    }
                }, function (err, result) {
                    if (err) {
                        throw err;
                    }
                    response.status(200);
                    response.json(result);
                    console.log("List of countries in " + request.body.continent + " " + JSON.stringify(result));
                });
            });

            You can check out more operations and details in the sample code in the repo I mentioned above . And you can drop any comment or question below regarding NodeJS with Cloudant .
            
            Next tutorials will be on more NodeJS REST APIs – with IBM services topics .  So please drop any suggestions as well, if any !