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Building Spatial Web Services with MongoDB + NodeJS in

Less than 30 Minutes

Steven Citron-PoustyPaaS Dust Spreader, Red Hat@TheSteve0

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Agenda

• Learn a little spatial

• Load some spatial data into mongo

• Do a query or two

• Repo for today’s code is here – https://github.com/openshift/openshift-mongo-node-express-example

SIGN UP CODE: jseverywhere

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Assumptions

1) You already know that Node.JS + Mongo is like chocolate and peanut butter

2) You can use the command line

3) You are comfortable with Mongo command line

4) Please ask questions – though since we only have 30 minutes they may have to wait until the end or after the session

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What is OpenShift?

Red Hat’s free platform as a service for applications in the cloud.

5 Dalbera on Flickr

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Kind of like Amazon, right? Nope.

7Cook24v on Flickr

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What’s supported?

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There’s more? What’s the catch?

• OpenShift is free-as-in-beer & free-as-in-freedom

• Three 512 MB RAM / 1 GB storage gears

• Need more resources, just ask!

• We are really in Developer Preview

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On to spatial!

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Spatial is fun

The only spatial functionality Mongo currently has is:

1) Near

2) Containment

All of it is laid out on one page:

http://www.mongodb.org/display/DOCS/Geospatial+Indexing

First link on a google search for “mongodb spatial indexing”

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Caveats

1. Assumes coords. are between -180 and 180

2. Can handle any 2D coordinates

3. Has methods to handle curvature of the earth (spherical)

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How to make it work

1) Put your coordinates into an arrary{ loc : [ 50 , 30 ] } //SUGGESTED OPTION

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

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

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

2) Make a 2d index

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

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Demo

1. I have an Node.JS app and a mongo instance running

2. Load some spatial data in JSON format

3. Make the 2d index

4. Do some fun spatial and MongoDB work

5. Show you the web services

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Conclusion

1. Spatial is easy and fun on Mongo

2. You can now build your own FourSquare or other checkin application.

3. You can also build your own field data entry system.

4. You can build and deploy your application quickly without having to think about infrastructure.

SIGN UP CODE: jseverywhere

http://openshift.redhat.com