Building spatial back ends with Node.js and MongoDB

1. OPENSHIFT
Workshop
PRESENTED
BY
Shekhar
Gulati
Building Spatial Back-ends
with Node.js and MongoDB

2. 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

3. Write an application and host it on internet
http://localjobsdemo-shekhargulati.rhcloud.com/
GOAL

4. CODE DU JOUR
https://github.com/shekhargulati/localjobs-nodejs

5. ● You know JavaScript
● You know Git
● You like to write code rather than
managing servers.
ASSUMPTIONS

6. There are no stupid questions only stupid
answers. So ask questions
ASK QUESTIONS

7. Node.js provides a purely event-driven ,
non-blocking infrastructure to script
highly concurrent programs.
NODE.JS

8. NODE.JS EXPLAINED

9. 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

10. Node.js is Server Side JavaScript.
● It provides runtime environment
● It provides a library
NODE.JS IS

11. ● 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

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

13. ● Hello World
● HTTP Server
NODE.JS IN ACTION

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

15. EXPRESS TO RESCUE
Web Application Framework for Node

16. ● Install Express
– npm install express -g
● Create a new Express application
– express --sessions --ejs hello-world

17. MONGODB

18. 18

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

19. Database → Database
Table → Collection
Row → Document
Index → Index
STEP 4 :
MONGODB TERMINOLOGY

20. DEMO TIME

21. 21

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

22. 22
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

23. 23
APP DEVELOPMENT

24. 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

25. 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

26. $ git clone https://github.com/shekhargulati/localjobs-nodejs.git
STEP 0 : CLONE REPO

27. $ git checkout 380e795c9b52235838c361f9052f188e054c0ea8
$ npm install -l
STEP 1 : APP INIT

28. $ git checkout b721308a8945b28019731791a5a1188ba3d855b6
$ npm install -l
STEP 2 : INDEX PAGE

29. $ git checkout edbec3f6df758e6287f7c8ded6098ada9262282
$ npm install -l
STEP 3 : SAVE JOB

30. $ git checkout 457eb572b0d74c649b56c26306a1d5bcdd01a9e1
STEP 4 : VIEW ALL JOBS

31. $ git checkout a9e50f4feb1448c924758ed968d8253da3c06070
Create MongoDB 2d Index
STEP 5 : SEARCH BY NEAR

32. $ git checkout 82a6cefe0514d1b81d0b8446412a16340465590d
STEP 6 : SEARCH BY GEONEAR

33. $ ./mongoimport --db localjobs --collection jobs –file jobs.json
STEP 7 : IMPORT DATA

34. 34
APPLICATION DEPLOYMENT

37. PaaS == Platform as a Service
A Cloud Application Platform
Code Deploy Enjoy
Save Time and Money
Code your app
Push-button
Deploy, and
your App is
running in
the Cloud!

38. 38
OpenShift
is
PaaS by Red Hat
Multi-language,
Auto-Scaling,
Self-service,
Elastic,
Cloud Application
Platform

39. 39
OUR STACK

40. 40
https://openshift.redhat.com/app/account/new
Promo code is JSCHANNEL13
CREATING OPENSHIFT
ACCOUNT

41. ● Free! No time limit
● 3 gears (like servers) - each 512 Mb RAM, 1 Gb disk
● Auto-scaling
● Simple pricing
BUT WAIT – THERE's MORE

42. 42
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

43. 43
git push

44. 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

45. QUESTIONS?