RoomSharp.Reactive 0.4.7

RoomSharp.Reactive

Lightweight reactive operators, computed views, query caching, and UI collection binding for RoomSharp. Includes optional Rx.NET adapters.

Installation

dotnet add package RoomSharp.Reactive

Observe + debounce

using RoomSharp.Reactive;

var todos = db.GetTableIdOrThrow("todos");

// Default debounce uses ReactiveDefaults.DefaultDebounceInterval (150ms)
var query = db.ObserveReactive(
    ct => new ValueTask<IReadOnlyList<Todo>>(db.TodoDao.GetAllAsync()),
    new ReactiveQueryOptions
    {
        DebounceInterval = TimeSpan.FromMilliseconds(200)
    },
    todos);

using var subscription = query.Subscribe(
    list => Render(list),
    error => Log(error));

QueryCache (single-flight + TTL)

using RoomSharp.Reactive;

var cache = new QueryCache(db);
var key = db.BuildCacheKey<IReadOnlyList<Todo>>("select * from todos", parameters: null);

var cached = db.ObserveCached(
    cache,
    key,
    ct => new ValueTask<IReadOnlyList<Todo>>(db.TodoDao.GetAllAsync()),
    new QueryCacheEntryOptions
    {
        Ttl = TimeSpan.FromSeconds(10),
        TableIds = new[] { db.GetTableIdOrThrow("todos") }
    },
    options: null,
    db.GetTableIdOrThrow("todos"));

using var sub = cached.Subscribe(
    list => Render(list),
    error => Log(error));

ComputedView (derived reactive value)

using RoomSharp.Reactive;

var todosQuery = db.ObserveReactive(
    ct => new ValueTask<IReadOnlyList<Todo>>(db.TodoDao.GetAllAsync()),
    db.GetTableIdOrThrow("todos"));

var stats = ComputedView.Combine(
    todosQuery,
    todos => new TodoStats(todos.Count),
    new ComputedViewOptions
    {
        DebounceInterval = TimeSpan.FromMilliseconds(200)
    });

using var sub = stats.Subscribe(
    value => UpdateStats(value),
    error => Log(error));

ObservableCollection binding (WPF/WinUI)

using RoomSharp.Reactive;
using System.Collections.ObjectModel;
using System.Threading;

var collection = new ObservableCollection<Todo>();

using var sub = query
    .AsObservable()
    .BindToObservableCollection(
        collection,
        SynchronizationContext.Current,
        keySelector: t => t.Id,
        mergeExisting: (existing, incoming) =>
        {
            existing.Title = incoming.Title;
            existing.IsDone = incoming.IsDone;
        });

Lightweight operators (no System.Reactive dependency)

using RoomSharp.Reactive;

var stream = query
    .AsObservable()
    .DistinctUntilChanged()
    .Throttle(TimeSpan.FromMilliseconds(150))
    .Buffer(TimeSpan.FromMilliseconds(250));

Rx.NET integration (optional)

using RoomSharp.Reactive.Rx;

var observable = query.ToObservable();
observable
    .Throttle(TimeSpan.FromMilliseconds(300))
    .DistinctUntilChanged()
    .Subscribe(list => Render(list));

Requirements

• RoomSharp 0.4.3+
• System.Reactive 6.0+ (only if you use the Rx integration)