building spatial back ends with node.js and mongodb

OPENSHIFTWorkshop

PRESENTEDBY

ShekharGulati

Building Spatial Back-ends with Node.js and MongoDB

AGENDA

➔ Learn a bit about Node.js and Express

➔ Learn some MongoDB basics

➔ Build a location aware Job search application

➔ Go live with a Node.js MongoDB powered app in ~ 45 mins

Write an application and host it on internet

http://localjobsdemo-shekhargulati.rhcloud.com/

GOAL

CODE DU JOUR

https://github.com/shekhargulati/localjobs-nodejs

● You know JavaScript● You know Git● You like to write code rather than

managing servers.

ASSUMPTIONS

There are no stupid questions only stupid answers. So ask questions

ASK QUESTIONS

Node.js provides a purely event-driven , non-blocking infrastructure to script

highly concurrent programs.

NODE.JS

NODE.JS EXPLAINED

Node.js goal is to provide an easy way to build scalable network applications.

Some ex. Web servers , TCP servers, Streaming server , Realtime apps, etc.

NODE.JS GOAL

Node.js is Server Side JavaScript.

● It provides runtime environment● It provides a library

NODE.JS IS

● Non Blocking I/O● Based on Google's Chrome V8 engine● 40k + modules● Active community● Multi platform – Windows , Mac , and Linux● Use single language for both client and

server.● JavaScript is language of Web.

WHY NODE.JS

● Go to http://nodejs.org/ and click install.● Install the downloaded package.

INSTALLING NODE.JS

● Hello World● HTTP Server

NODE.JS IN ACTION

● Routing support● Template support● Error handling● Etc.

EXPRESS TO RESCUE

Web Application Framework for Node

● Install Express– npm install express -g

● Create a new Express application– express --sessions --ejs hello-world

MONGODB

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Open Source NoSQL document datastore– JSON style documents

Schema-less– Each document is heterogeneous, and may have completely

unique structure compared to other documents

Fast and horizontally scalable Rich query language Rich documents Easy to get running Geospatial indexing

WHAT IS MONGODB

Database → Database

Table → Collection

Row → Document

Index → Index

STEP 4 : MONGODB TERMINOLOGY

DEMO TIME

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What is it for? Find all the MongoDB jobs near me – Proximity Queries Find all the MongoDB jobs within Bangalore – Bounded

Queries Find all the MongoDB job at this location – Exact Queries

● Supports only two dimensional indexes. You can only have one geospatial index per collection. By default, 2d geospatial indexes assume longitude

and latitude have boundaries of -180 inclusive and 180 non-inclusive (i.e. [-180, 180))

GEOSPATIAL INDEXING BASICS

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1) Put your coordinates into an array

{ loc : [ 50 , 30 ] } //SUGGESTED OPTION

{ loc : { x : 50 , y : 30 } }

{ loc : { foo : 50 , y : 30 } }

1) { loc : { lon : 40.739037, lat: 73.992964 } }

2) Make a 2d index

db.places.ensureIndex( { loc : "2d" } )

3) If you use latitude and longitude as your coordinate system, always store longitude first. MongoDB’s 2d spherical index operators only recognize [ longitude, latitude] ordering.

HOW TO MAKE IT WORK

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APP DEVELOPMENT

LocalJobs : Location Aware Job Search App

Functionalities or User stories or Features

1. As an Employer , I should be able to register my company

2. As an Employer, I should be able to post jobs

3. As a Job seeker , I should be able to register myself with application

4. As a Job seeker , I should be able to search jobs near to my current location.

5. As a Job seeker , I should be able to apply a job

6. Etc...

APP -- USER STORIES

Prioritize the functionalities or user stories or features

– As an Employer, I should be able to post jobs

– As a Job seeker , I should be able to search jobs near to my current location.

– As a Job seeker , I should be able to see all the jobs

PRIORITIZE

$ git clone https://github.com/shekhargulati/localjobs-nodejs.git

STEP 0 : CLONE REPO

$ git checkout 380e795c9b52235838c361f9052f188e054c0ea8

$ npm install -l

STEP 1 : APP INIT

$ git checkout b721308a8945b28019731791a5a1188ba3d855b6

$ npm install -l

STEP 2 : INDEX PAGE

$ git checkout edbec3f6df758e6287f7c8ded6098ada9262282

$ npm install -l

STEP 3 : SAVE JOB

$ git checkout 457eb572b0d74c649b56c26306a1d5bcdd01a9e1

STEP 4 : VIEW ALL JOBS

$ git checkout a9e50f4feb1448c924758ed968d8253da3c06070

Create MongoDB 2d Index

STEP 5 : SEARCH BY NEAR

$ git checkout 82a6cefe0514d1b81d0b8446412a16340465590d

STEP 6 : SEARCH BY GEONEAR

$ ./mongoimport --db localjobs --collection jobs –file jobs.json

STEP 7 : IMPORT DATA

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APPLICATION DEPLOYMENT

PaaS == Platform as a Service

A Cloud Application Platform

Code Deploy Enjoy

Save Time and MoneyCode your app

Push-button Deploy, and your App is running in the Cloud!

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OpenShiftis

PaaS by Red Hat

Multi-language,Auto-Scaling,Self-service,

Elastic,Cloud Application

Platform

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OUR STACK

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https://openshift.redhat.com/app/account/newPromo code is JSCHANNEL13

CREATING OPENSHIFT ACCOUNT

● Free! No time limit

● 3 gears (like servers) - each 512 Mb RAM, 1 Gb disk

● Auto-scaling

● Simple pricing

BUT WAIT – THERE's MORE

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rhc create-app localjobs nodejs mongodb-2.2 --from-code=https://github.com/shekhargulati/localjobs-nodejs.git

Lot of other tasks you can do with rhc – tail log, app management, cartridge management , ssh management , namespace management, etc. Run rhc -h for details

DEMO : LOCALJOBS APP

RHC is only required for infrastructure tasks

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git push

IN CASE YOU CARE

• Shekhar Gulati – Works at Red Hat

• Principal OpenShift Developer Evangelist

• Java / Python/ JavaScript / NoSQL / Cloud Guy

• Twitter Handle : shekhargulati

• Github https://github.com/shekhargulati

• Slides https://speakerdeck.com/shekhargulati

QUESTIONS?