The document summarizes the New York Times' open source Store library for Android, which provides a unified way to fetch, parse, cache, and retrieve data in Android applications. The Store abstracts these processes and enforces unidirectional data flow while exposing data as RxJava Observables. Key aspects include using StoreBuilders to configure Stores, adding fetchers and parsers, using middleware like GsonSourceParser, and enabling disk caching. The document also provides guidance on open sourcing a new library, including using Android Studio and GitHub to set up the project, adding documentation like README and license, and publishing to Maven Central.

1. Open Sourcing the Store
What we open sourced and how you can too!
Mike Nakhimovich - New York Times

2. Agenda For Today
Walkthrough of New York Times’ first Android
Open Source Library
How you can make open source a library
yourself

3. 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

4. Android === Open Source
Libraries fill gaps left by framework
Network Client? OKHTTP/Retrofit
Threading/Functional Programming? RxJava
Dependency Injection? Dagger
View Bindings? Butterknife

5. 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

6. Introducing Store
https://github.com/NYTimes/Store

7. A Store abstracts fetching, parsing,
caching, and retrieval of data in
your application.

8. Stores are configurable and enforce
uni-direcitonal data flow while
exposing data as RxJava
Observables

9. Sounds Great, but how do I
use them?

10. Add to build.gradle
compile 'com.nytimes.android:store:1.0.1'

11. Open A Store
Store<Article> articleStore = StoreBuilder.<Article>builder()
.open();

12. 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();

13. 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();

14. 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}});

15. Fetch Dataflow (Unidirectional)
Same request <1min will
get throttled response

16. Getting Cached Data

17. 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

18. Note: if nothing
cached get() will act
exactly like fetch()
Get Dataflow

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

20. 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();

21. Dataflow with Parser

22. Introducing Middleware

23. 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);} })

24. 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))

25. 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();

26. Dataflow with Cache

27. 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();

28. Hope you’ll use Stores
And contribute back to the project

29. Part 2
How to go from 0 to Open
Source Project

30. Android Studio
Create a Project

31. Add a library module

32. Add some code to library

33. Use Android Studio to
create Github Project

34. Add a
Descriptive
Readme.md
● Who is project for?
● What was motivation for creation?
● What does it do?
● How does it do it?

35. Add a License

36. Part 2B: How to upload
project to Maven Central

37. Create a Sonatype Jira
Account (yes really)

38. Open A ticket to claim an organization

39. Wait for Response

40. Whats a GPG Key?

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

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

43. Add to library module gradle.properties

44. Add to top level build.gradle

45. Add Gradle Maven Plugin & Script
https://github.com/NYTimes/Store/blob/develop/gradle/maven-push.gradle

46. Run UploadArchives task

47. Go To Nexus Staging Repo to Verify
https://oss.sonatype.org/index.html#stagingRepositories

48. Close staging Repo and Deploy to Maven Central

49. Update jira with successful
first upload

50. Enable Travis

51. Add Travis.yml

52. Add Contributing.md

53. Submit a talk to GDG

54. Thanks for listening