march 2014 meetup baug android and google app engine

Using Google Datastore for Android apps

Gaurang Kanvinde(gaurang.kanvinde@drawtyme.com)

An example of how Google Datastore was used for DrawTyme

(http://drawty.me/ua44g)

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22-Mar-2014 2©2014 DrawTyme Technologies Pvt. Ltd., All rights reserved

Overview of Google Datastore

• Non-relational database• Cloud based• Ready to use• Requires Google App Engine and Google Endpoints

– Very inexpensive and simple to use– Can be programmed in many languages – Java, Python, etc– Extensive documentation available

22-Mar-2014 3©2014 DrawTyme Technologies Pvt. Ltd., All rights reserved

The Development Environment

• Eclipse for Java EE - Download and install• Google Plugin for Eclipse – Instructions to install

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Setting up Google App Engine

• Create a project on Google App Engine - Link to Console• Remember it’s Project-ID

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The nuts and bolts

• Two main directories– src

• Contains all the code of the app– war

• Contains a sub-directory named WEB-INF– Contains the compiled binaries of the code in “src”– Contains other dependencies– Everything else that goes into the app

• Contents of this directory will be deployed to the Google App Engine– index.html (if any, will go here)

• Code available at: DrawTymeExample.zip

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Understanding the code

• The Video class

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Writing the API

• Defining the API class with @Api annotation

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Writing the API

• Adding authenticated methods

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Writing the API

• Adding unauthenticated methods

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Preparing to Deploy

• Write app-ID of your project in war/WEB-INF/appengine-web.xml

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Setting up Datastore Indexes

• war/WEB-INF/datastore-indexes.xml– If you get the contents of this file wrong, Google App Engine suggests

the correct content for you!

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A quick peek at the Web-app

• war/js/backend.js– Initialising the API

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A quick peek at the Web-app

• war/js/backend.js– Calling API functions

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Deploying to App Engine

• Use Google Plugin button– Deploy to App Engine– Sign-in to the App Engine is required

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It works!

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Porting to Android

• AppEngine SDK has all the tools!– Use endpoints.cmd or endpoints.sh

• Eg: $PATH_TO_SDK/bin/endpoints.cmd get-client-lib \ com.example.api.classname

– Android code will be generated and stored in myapi-v1-java.zip

22-Mar-2014 17©2014 DrawTyme Technologies Pvt. Ltd., All rights reserved

Locating the Android code for Endpoints

22-Mar-2014 18©2014 DrawTyme Technologies Pvt. Ltd., All rights reserved

And we are done!

• Have fun using Google App Engine!

• Contact meGaurang.kanvinde@drawtyme.comTwitter: @gaurangrk

• DrawTymehttp://www.drawtyme.comTwitter: @drawtymeFacebook: https://www.facebook.com/drawtymeBlog: http://blog.drawtyme.com