Design discussion: OfflineDbContext

[adrianhall]

I'd like to garner opinions on this API.

The new client will be centered around offline capabilities by requiring you to integrate into an Entity Framework Core DbContext - or rather a sub-class of it (called OfflineDbContext). Here is the proposed typical OfflineDbContext definition:

public class MyOfflineDbContext(DbContextOptions<MyOfflineDbContext> options) : OfflineDbContext(options)
{
  // Your offline data sets are defined as normal; you can also use OnModelCreating() as normal as long as you call base.
  public DbSet<Movie> Movies => Set<Movie>();

  // This is the setup for the remote dataset
  protected override HttpClient GetHttpCleint()
    => new() { BaseAddress = new Uri("http://my-datasync-service.azurewebsites.net/");

  // Optional - if not defined, it uses /tables/{entity}s - e.g. class Movie gets turned into /tables/movies
  // You can also return an absolute URI, in which case you don't need to specify a BaseAddress on the HttpClient
  protected override Uri GetDatasyncUriForEntityType(Type entityType)
    => new Uri($"/tables/{entityType.Name.ToLowerInvariant()}s", UriKind.Relative); 
}

If you want to pull the movies table, you can use:

var pullResult = await context.PullAsync<Movie>();

If you want to use a query, you can use:

var query = context.Movies.CreateDatasyncQuery().Where(x => x.BestPictureWinner);
var pullResult = await context.PullAsync<Movie>(query);

Thoughts on this overall flow for pulling data?

(And yes, pushing, I'll be covering remote table access and pushing tables in a later discussion)

[adrianhall]

Option #2: Using an On… protected function:

public class MyOfflineDbContext(DbContextOptions<MyOfflineDbContext> options) : OfflineDbContext(options)
{
  // Your offline data sets are defined as normal; you can also use OnModelCreating() as normal as long as you call base.
  public DbSet<Movie> Movies => Set<Movie>();

  // Use OnDatasyncInitialization() to set datasync settings
  Protected override void OnDatasyncInitialization(DatasyncContextBuilder contextBuilder)
  {
    contextBuilder.SetHttpClient(new HttpClient() { BaseAddress = “https://my-datasync-server.azurewebsites.net/“ });
    ContextBuilder.Entity<Movie>().SetUri(new Uri(“/tables/movies”, UriKind.Relative));
  }
}

(With apologies for capitalization - apparently, writing code on an iPad is hard)

[adrianhall]

Based on the complete lack of replies, I’m going to assume no-one cares as long as it works. I’m going to use Option 2 (above) - having a protected builder initialization method (which is how OnConfiguring and OnModelCreating work as well).