Project Summary

In this project, we will go over how to use massive with a node server to connect to a postgres database.

Setup

• Run npm install.
• Review the index.js file to get familiar with it.

Step 1

Summary

In this step, we'll install massive into our project and require it in index.js.

Instructions

• Run npm install --save massive dotenv
• Require massive underneath cors.
• Require and configure dotenv below massive.

Solution

index.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const massive = require('massive');
require('dotenv').config()

const app = express();
app.use( bodyParser.json() );
app.use( cors() );

const port = process.env.PORT || 3000
app.listen(port, () => { console.log(`Server listening on port ${port}`) } );

Step 2

Summary

In this step, we'll connect SQLTabs to our Heroku databse. We'll then add a new table to our Heroku database called airplanes.

Instructions

• Open SQLTabs.
• Connect to your Heroku database with SQLTabs by using the URI connection string.
• Create the following airplanes table:
  • CREATE TABLE airplanes

    CREATE TABLE airplanes (
      PlaneID SERIAL PRIMARY KEY NOT NULL,
      PlaneType varchar(40) NOT NULL,
      PassengerCount integer NOT NULL
    );

Step 3

Summary

In this step, we'll establish a connection to our database using massive in index.js.

Instructions

• Open index.js.
• Create a file named .env
  • Make sure to add .env to your .gitignore
• Open your .env and add a variable named CONNECTION_STRING that equals the URI connection string from your Heroku database.
  • Make sure to add ?ssl=true at end of your connection string.
  • There should be no quotes around the connection string.
• Invoke massive and pass in the connection string by accessing the variable CONNECTION_STRING from the .env file on the process object process.env.CONNECTION_STRING. This will return a promise. Chain a .then that has one parameter called dbInstance and then returns app.set('db', dbInstance). This will give our express application access to our database.

Solution

.env

CONNECTION_STRING=postgres://username:password@host/dbname?ssl=true

index.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const massive = require('massive');
require('dotenv').config()

const app = express();
massive( process.env.CONNECTION_STRING ).then( dbInstance => app.set('db', dbInstance) );

app.use( bodyParser.json() );
app.use( cors() );

const port = process.env.PORT || 3000
app.listen(port, () => { console.log(`Server listening on port ${port}`) } );

Step 4

Summary

In this step, we will add some seed data to our database using the the files already created in the db folder.

Instructions

• Open index.js.
• Modify the massive .then to set db on app and also call dbInstance.new_planes.
  • Chain a .then that has a parameter called planes. Return a console.log of planes.
  • Chain a .catch that has a parameter called err. Return a console.log of err.
• Restart/Run the API so the planes get added to the table.
• Comment out dbInstance.new_planes so we don't get duplicate planes.

Solution

index.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const massive = require('massive');
require('dotenv').config()

const app = express();
massive( process.env.CONNECTION_STRING ).then( dbInstance => {
  app.set('db', dbInstance);

  // dbInstance.new_planes()
  //   .then( planes => console.log( planes ) )
  //   .catch( err => console.log( err ) );
});

app.use( bodyParser.json() );
app.use( cors() );

const port = process.env.PORT || 3000
app.listen(port, () => { console.log(`Server listening on port ${port}`) } );

Step 5

• Open index.js.
• Underneath the comment of new_planes, call dbInstance.get_planes.
  • Chain a .then that has a parameter called planes. Return a console.log of planes.
  • Chain a .catch that has a parameter called err. Return a console.log of err.

Solution

index.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const massive = require('massive');
require('dotenv').config()

const app = express();
massive( process.env.CONNECTION_STRING ).then( dbInstance => {
  app.set('db', dbInstance);

  // dbInstance.new_planes()
  //   .then( planes => console.log( planes ) )
  //   .catch( err => console.log( err ) );
  
  dbInstance.get_planes()
    .then( planes => console.log( planes ) )
    .catch( err => console.log( err ) );
});

app.use( bodyParser.json() );
app.use( cors() );

const port = process.env.PORT || 3000
app.listen(port, () => { console.log(`Server listening on port ${port}`) } );

Step 6

Summary

In this step, we will use our dbInstance in a controller file instead of in index.js.

Instructions

• Open controller.js.
• Use module.exports to export an object.
• Add a getPlanes property to the object that equals a function with a req, res, and next parameter.
• Get the dbInstance by using req.app.get('db').
• Using the dbInstace call get_planes.
  • Chain a .then with a parameter called planes. Then use res to send back planes and a status of 200.
  • Chain a .catch with a parameter called err. Console log the err and use res to send a status 500.
• Open index.js.
• Require controller.js.
• Create a GET endpoint on /api/planes/ that calls controller.getPlanes.
• In your index.js file, comment out dbInstance.get_planes as this is now setup in the controller.

Solution

controller.js

module.exports = {
  getPlanes: ( req, res, next ) => {
    const dbInstance = req.app.get('db');

    dbInstance.get_planes()
      .then(planes => { res.status(200).send(planes); })
      .catch( err => { 
        console.log(err);
        res.status(500).send(err);
      });
  }
};

index.js

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const massive = require('massive');
require('dotenv').config()
const controller = require('./controller');

const app = express();
massive( process.env.CONNECTION_STRING ).then( dbInstance => {
  app.set('db', dbInstance);

  // dbInstance.new_planes()
  //   .then( planes => console.log( planes ) )
  //   .catch( err => console.log( err ) );

  //dbInstance.get_planes()
  //  .then( planes => console.log( planes ) )
  //  .catch( err => console.log( err ) );
});

app.use( bodyParser.json() );
app.use( cors() );

app.get('/api/planes', controller.getPlanes);

const port = process.env.PORT || 3000
app.listen(port, () => { console.log(`Server listening on port ${port}`) } );

Step 7

Summary

In this step, we'll modify the get_planes SQL file to use a parameter.

Instructions

• Open get_planes.sql.
• At the end of the first line, add WHERE PassengerCount > $1;
• Open controller.js.
• Pass in an array as the first parameter for dbInstance.get_planes.
  • Use number 25 as the first element of the array.

Solution

get_planes.sql

SELECT * FROM airplanes WHERE PassengerCount > $1;

controller.js

module.exports = {
  getPlanes: ( req, res, next ) => {
    const dbInstance = req.app.get('db');

    dbInstance.get_planes([25])
      .then(planes => { res.status(200).send(planes); })
      .catch( err => { 
        console.log(err);
        res.status(500).send(err);
      });
  }
};

Contributions

If you see a problem or a typo, please fork, make the necessary changes, and create a pull request so we can review your changes and merge them into the master repo and branch.

Copyright

© DevMountain LLC, 2017. Unauthorized use and/or duplication of this material without express and written permission from DevMountain, LLC is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to DevMountain with appropriate and specific direction to the original content.