Open Sourcing the StoreWhat we open sourced and how you can too!

Mike Nakhimovich - New York Times

Agenda For TodayWalkthrough of New York Times’ first Android

Open Source Library

How you can make open source a library yourself

Problem Set

Modern Android Apps need their data representations to be fluid and always available.

Users expect their UI experience to never be compromised (blocked) by new data loads

International users expect minimal data downloads

Android === Open Source

Libraries fill gaps left by framework

Network Client? OKHTTP/Retrofit

Threading/Functional Programming? RxJava

Dependency Injection? Dagger

View Bindings? Butterknife

Android === Open Source

Libraries fill gaps left by framework

Network Client? OKHTTP/Retrofit

Threading/Functional Programming? RxJava

Dependency Injection? Dagger

View Bindings? Butterknife

Store? Data Flow & Caching

Introducing Store

https://github.com/NYTimes/Store

A Store abstracts fetching, parsing, caching, and retrieval of data in

your application.

Stores are configurable and enforce uni-direcitonal data flow while

exposing data as RxJava Observables

Sounds Great, but how do I use them?

Add to build.gradle

compile 'com.nytimes.android:store:1.0.1'

Open A Store

Store<Article> articleStore = StoreBuilder.<Article>builder()

.open();

Add a fetcher

public interface Fetcher<T> {

Observable<T> fetch(BarCode barCode);

}

Store<Article> articleStore = StoreBuilder.<Article>builder()

.fetcher(barCode -> api.getArticle(barCode.getKey()))

.open();

Or NonObservable Fetcher

Use nonObservbleFetcher when connecting to a synchronous & non observable API

Store<Article> articleStore = StoreBuilder.<Article>builder()

.nonObservableFetcher(barCode -> api.getArticle(barCode.getKey()))

.open();

Call your Store with a Barcode...

BarCode barcode = new BarCode("Article", "42");

articleStore.fetch(barcode)

.subscribeOn(Schedulers.io())

.observeOn(AndroidSchedulers.mainThread())

.subscribe(new Observer<Article>() {

public void onCompleted() {}

public void onError(Throwable throwable) {//handle error} public void onNext(Article article) {//bind Article to UI}});

Fetch Dataflow (Unidirectional)

Same request <1min will get throttled response

Getting Cached Data

articleStore.get(barcode)

.subscribeOn(Schedulers.io())

.observeOn(AndroidSchedulers.mainThread())

.subscribe(new Observer<Article>() {

public void onCompleted() {}

public void onError(Throwable throwable) {//handle error} public void onNext(Article article) {//bind Article to UI}});

Note: if nothing cached get() will act exactly like fetch()

Getting Cached Data

Note: if nothing cached get() will act exactly like fetch()

Get Dataflow

What happens if we need to transform response?Adding a Parser

Adding a Parser

Store<Article> articleStore = ParsingStoreBuilder.<BufferedSource, Article>builder() .fetcher(barCode -> api.getSource(barCode.getKey()))

.parser(source -> {

try (InputStreamReader reader = new InputStreamReader(source.inputStream())) {

return gson.fromJson(reader, Article.class);

} catch (IOException e) {

throw new RuntimeException(e);} })

.open();

Dataflow with Parser

Introducing Middleware

Use our Middleware

Before:

.parser(source -> {

try (InputStreamReader reader = new InputStreamReader(source.inputStream())) {

return gson.fromJson(reader, Article.class);

} catch (IOException e) {

throw new RuntimeException(e);} })

Use our Middleware

Before:.parser(source -> {

try (InputStreamReader reader = new InputStreamReader(source.inputStream())) {

return gson.fromJson(reader, Article.class);

} catch (IOException e) {

throw new RuntimeException(e);} })

After:

.parser(new GsonSourceParser<>(gson, Article.class))

Disk Caching

ParsingStoreBuilder.<BufferedSource, Article>builder() .fetcher(barCode -> api.getSource(barCode.getKey())) .parser(new GsonSourceParser<>(gson, Article.class)) .persister(new Persister<BufferedSource>() { public Observable<BufferedSource> read(BarCode barCode) { return Observable.fromCallable(() -> diskCache.get(barCode)); } public Observable<Boolean> write(BarCode barCode, BufferedSource source) { diskCache.save(barCode, source); return Observable.just(true); }}) .open();

Dataflow with Cache

No Need to implement yourself

articleStore = ParsingStoreBuilder.<BufferedSource, Article>builder() .fetcher(barCode -> api.getSource(barCode.getKey())) .parser(new GsonSourceParser<>(gson, Article.class)) .persister(new SourcePersister(FileSystemFactory.create(getFilesDir()))) .open();

Hope you’ll use StoresAnd contribute back to the project

Part 2How to go from 0 to Open Source Project

Android Studio Create a Project

Add a library module

Add some code to library

Use Android Studio to create Github Project

Add a Descriptive Readme.md

● Who is project for?

● What was motivation for creation?

● What does it do?

● How does it do it?

Add a License

Part 2B: How to upload project to Maven Central

Create a Sonatype Jira Account (yes really)

Open A ticket to claim an organization

Wait for Response

Whats a GPG Key?

Use GPG to create a keyhttp://central.sonatype.org/pages/working-with-pgp-signatures.html

Add to top level gradle.properties (don’t check into github!)

Add to library module gradle.properties

Add to top level build.gradle

Add Gradle Maven Plugin & Script

https://github.com/NYTimes/Store/blob/develop/gradle/maven-push.gradle

Run UploadArchives task

Go To Nexus Staging Repo to Verify

https://oss.sonatype.org/index.html#stagingRepositories

Close staging Repo and Deploy to Maven Central

Update jira with successful first upload

Enable Travis

Add Travis.yml

Add Contributing.md

Submit a talk to GDG

Thanks for listening