Go reactive with Realm and Xamarin.Forms

Transcript

1. ROME - APRIL 13/14 2018 Andrea Ceroni Go reactive with Realm and Xamarin Forms
2. Andrea Ceroni andrea.ceroni@elfo.net @andrekiba http://www.linkedin.com/in/andreaceroni elfo.net klabcommunity.org
3. Realm + Xamarin.Forms
4. Xamarin.Forms
5. cosa è Realm?? Reactive Mobile Database with Live Objects
6. caratteristiche non è un ORM costruito su SQLite o simili non è un Key-Value store (JSON) ma un db a tutti gli effetti completamente riscritto, core in C++ (open source) Swift, Objective-C, Java, JavaScript .NET con Xamarin (iOS, Android, Mac, UWP, .NET Framework) client + server (pensato per essere offline first)
7. varrealm = Realm.GetInstance(config); ok ma come si presenta?
8. perchè Realm
9. MVCC (multiversion concurrency control) R A B C D E V1 1) R A B C D E V1 2) R1 A1 C1 V2 R1 A1 B C1 D E V2 3) R A C garbage
10. zero copy e native links native objects ORM traduce in istruzioni SQL crea connessione DB invia le istruzioni al disco esegui la query leggi i dati deserializza e copia in formato intermedio in memoria ritorna gli oggetti finali copia in memoria in formato appropriato per il linguaggio native objects realm db file virtual memory mapped native links
11. lazy loading non si può leggere meno di una "pagina" però le proprietà sono gruppate "in verticale" le proprietà non utilizzare non vengono lette si evitano inutili accessi al disco
12. 4 concepts transactions objects modify notifications trigger queries make up UI events, network, ...
13. objects public class Dog : RealmObject { [MapTo("name")] [Required] public string Name { get; set; } public int Age { get; set; } public Person Owner { get; } } public class Person : RealmObject { [PrimaryKey] public int Id { get; set; } public string Name { get; set; } public IList<Dog> Dogs { get; } } to one to many inverse [Backlink(nameof(Dog.Owner))] public IQueryable<Dog> Dogs { get; }
14. queries var artu = realm.Find<Dog>(6); IQueryable<Dog> puppies = realm.All<Dog>() .Where(d => d.Age < 2); var mila = realm.All<Dog>() .FirstOrDefault(d => d.Name == "Mila"); https://realm.io/docs/dotnet/latest/api/linqsupport.html
15. notifications realm.RealmChanged += (s, e) => { //do something } var subscription = realm.All<Dog>() .SubscribeForNotifications((sender, changes, error) => { //cosa è stato inserito, elimintato, modificato }); //later subscription.Dispose(); var mila = new Dog(); realm.Write(() => realm.Add(mila)); mila.PropertyChanged += (sender, e) => { //do something }
16. transactions var realm = Realm.GetInstance(configuration); realm.Write(() => { var andre = realm.Add(new Person() { Id = 6, Name = "Andrea" }); var mila = new Dog() { Name = "mila", Age = 1, } andre.Dogs.Add(mila); mila.Owner = andre; });
17. Realm Mobile Platform Realm Database + Realm Object Server
18. Realm Object Server https://realm.io/products/realm-studio/
19. REST sync
20. 2-way sync
21. autenticazionee sync configuration var credentials = Credentials.UsernamePassword("username", "pass"); var authUrl = new Uri("http://realmAuthServerAddress:9080"); var user = await User.LoginAsync(creadentials, authUrl); var serverUrl = new Uri("realm://realmServerAddress:9080/~/default"); var syncConfig = new SyncConfiguration(user, serverUrl); var realm = Realm.GetInstance(syncConfig); var realm = await Realm.GetInstanceAsync(syncConfig);
22. Demo
23. realm.All<Question>() .SubscribeForNotifications((...) => { if(iKnowTheAnswerJ) Answer(); });
24. Grazie! andrea.ceroni@elfo.net @andrekiba http://github.com/andrekiba http://www.linkedin.com/in/andreaceroni https://creativecommons.org/licenses/by-nc-sa/3.0/