Users of mobile apps are just that, mobile. And as such, any mobile app that deals with data needs to work reliably in all environments; from a WiFi connection with a high throughput Internet connection, to an intermittent cell connection that keeps dropping - it even needs to work for prolonged periods of offline use. Not only that, when the device gets back online, your app needs to gracefully handle data synchronization and any data conflicts as well. In this session, I will share with you hard earned lessons on how to solve the problem of online/offline data resiliency and synchronization using Azure Mobile App Services based on using it in multiple Xamarin projects. You will learn how to solve the issues that arise with improper client-side data schemas, pushing data to the server without knowing when the connection will be interrupted, and reconciling conflicting data between the server and the app. At the end of this session you'll be well equipped to have your app ready for anything.

1. Lessons Learned from Making
Apps Resilient
Matthew Soucoup
Sr Cloud Developer Advocate
@codemillmatt

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Open source C#
Cross-platform
client SDK
FlexibleExtremely Powerful

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Xamarin, iOS, Android
and Windows SDKs
Offline sync
R
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Offline Sync Data Connections
User Authentication
Push Notifications
Backend

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Silent data pushConflict resolution
Offline dataClient-side schemas

16. Client-side
schemas

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-Matt … just now

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Server-side
ICollection<T>
$expand must
be used
TableController<T>
doesn’t $expand
Read-only
results
Obey OData

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Customized
Web APIs

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Optimize for MVVMOptimize for bandwidth
Mobile specific APIsFlat data (1:1)

31. Offline data

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38. Demo

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No need to push
data immediately
Only store data
offline when it
makes sense
Only do large
pushes on WiFi

40. Conflict
resolution

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CreatedAtId UpdatedAt

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Byte array
On push, Zumo
takes care of
updating value

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Server wins
Hybrid – combo
of both win

46. Demo

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Don’t ask the user if
their data should win
Different exceptions for
offline vs online push
Never mess with the
version column (normally)
Push shared data ASAP

48. Silent push

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58. Demo

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Spend time with
APNS and Firebase
Azure Notification
Hub templates

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Silent data pushConflict resolution
Offline dataClient-side schemas

61. Thank you!
Matthew Soucoup
Sr Cloud Developer Advocate
@codemillmatt
https://msou.co/codemash-2018