Picture Contest App 🌁

Backend application implemented as a REST API for a picture contest application

The app lists all the entrants with their favourite sight. The entrant model stores a location as it will be showed as pin in a map at the frontend. The user can vote a maximum of 3 entrants every 10 minutes, and those votes will be updated in real time.

Technology used: Node.js, Express.js, MongoDB and mongoose.js

Getting started

To get the Node server running locally:

• Clone this repo.
• Set up MongoDB locally. Link to get started (Click on 'Community Server' Tab to download).

  If you have homebrew in your machine, use the following command in your Terminal: brew install mongodb. And then activate it with the command: brew services start mongodb.

• npm install to install all the dependencies.
• node index.js to start the local server (You will see logged in your console 'Server listening').
• View in browser at http://localhost:5000

Code Overview

Dependencies

This is only information about the dependencies used in the project. Using the command npm install as explained before, they will all be installed, as they are already included in the package.json file.

• expressjs - Light-weight web application framework
• mongoose - For modeling and mapping MongoDB data to javascript
• mongoose-validator - Validators for Mongoose schemas
• body-parser - Node.js body parsing middleware
• node-config - Organizes hierarchical configurations for your app deployments
• cookie-parser - Parses cookies and puts the cookie information on req object in the middleware
• faker - for generating fake data for seeding the database and tests
• pug - high-performance template engine implemented with JavaScript for Node.js and browsers
• ava - Test runner
• nyc - Command line interface to use with AVA
• supertest - Provides a high-level abstraction for testing HTTP

Application Structure

• index.js - entry point of our application.

• app.js- defines our express server and the Error Handling middelware.

• database-connection.js- defines the connection to our MongoDB database.

• routes/ - This folder contains the routes definitions for our API.

• models/ - This folder contains the models used in our application, using Mongoose schema definitions.

• services/ - Contains the files where we define the methods to connect to our database.

• views/- The view files of our application using the pug template.

• ìndex.html - This html file will define our main view structure to be afterwards modelated by our different pug views. Here we will also implement the axios script that will allow us to make real time POST and GET requests from the Google Chrome console.

Error Handling

In the file app.js we define our error-handling middleware for handling any possible error in our application and be able to show error messages that the user/client can understand.

Every Error ocurred at the database or Schema level will be propagated until this stage to be properly handled.

We will consider different types of error:

• 409 - When the user/entrant tries to use an email that has been already used for another user.

• 400 - When the user introduces empty or non valid data in the request.

• 429 - When the user performs more than three votes in 10 minutes.

• 500 - When any other internal error ocurrs.

API Endpoints

Get a list of entrants with their votations

GET

/contest/entrant/all

Add a new entrant

POST

/contest/entrant/

The information of the entrant will be defined on the body request.

Example:

{ firstName: 'John', lastName: 'Evans', email: 'johnevans567@gmail.com', pictureUrl: "http://...", location: { type: 'Point', coordinates: [-564638, 332432] }

All fields are required, as we will need them for the different features of the app (like pictureUrl or location to show it on the map).email is an unique field, so if there is already an entrant in the database with the same email, the user will receive a 409 response with the informative error.

Add a new user

POST

/contest/user/

The information of the user will be defined on the body request.

Example:

{ firstName: 'Marina', lastName: 'Heart', email: 'mar_heart@gmail.com'}

email is a required and unique field. If there is already an user in the database with the same email, the user will receive a 409 response with the informative error.

Make a votation

POST

/contest/votation'

body: { entrantId: **THE_ENTRANT_ID**, userId: **THE_USER_ID**}

entrantId and userId are required fields.

If the votation is succesful, the entrant votes (an array with the userIds that performed the vote) will be updated. This way the votes will be easy to count and will also allow us to get more information about the user that performed the vote.

Every user can only vote 3 entrants every 10 minutes. This will be correctly handled by the route checks and will show any encoutered error to the user.

Helpful Software

• I recommend using Robomongo (now called Robo 3T) to manage easily your MongoDB database.

• You can use Axios or Postman to perform the GET and POST requests.