/// <summary>
/// Convert the received value into an <see cref="IActionResult"/>.
/// <para>
/// Catches <see cref="ValidationException"/> and converts it to
/// an appropriate <see cref="IActionResult"/>.
/// </para>
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="mapping">
/// The function to convert the value into an <see cref="IActionResult"/>.
/// </param>
/// <returns>An instance of <see cref="IProviderObservable{IActionResult}"/>.</returns>
public static IProviderObservable <IActionResult> ToActionResult <TSource>(
this IProviderObservable <TSource> observable,
Func <TSource, IActionResult> mapping) =>
observable.Map(mapping)
.Catch((ValidationException exception) =>
{
var actionResult = exception.Error == null
? ToStatusResult(exception) : ToObjectResult(exception);
return(Observable.Single(actionResult, observable.ServiceProvider));
});
/// <summary>
/// Emits the first element of a sequence, or a default
/// value if the sequence contains no elements.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> FirstOrDefault <TSource>(
this IProviderObservable <IQueryable <TSource> > observable) =>
observable.Map(s => s.FirstOrDefault());
/// <summary>
/// Emits the first element of a sequence that satisfies a
/// specified condition or a default value if no such element is found.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="predicate">A function to test each element for a condition.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> FirstOrDefault <TSource>(
this IProviderObservable <IQueryable <TSource> > observable,
Expression <Func <TSource, bool> > predicate) =>
observable.Map(s => s.FirstOrDefault(predicate));
/// <summary>
/// Specifies additional related data to be further included based on a
/// related type that was just included.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <typeparam name="TPreviousProperty">The type of the previous property.</typeparam>
/// <typeparam name="TProperty">The type of the property.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="navigationPropertyPath">
/// A lambda expression representing the navigation property to be
/// included (<c>t => t.Property1</c>).
/// </param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <IIncludableQueryable <TSource, TProperty> > ThenInclude <TSource, TPreviousProperty, TProperty>(
this IProviderObservable <IIncludableQueryable <TSource, TPreviousProperty> > observable,
Expression <Func <TPreviousProperty, TProperty> > navigationPropertyPath)
where TSource : class =>
observable.Map(s => s.ThenInclude(navigationPropertyPath));
/// <summary>
/// Creates and emits a <see cref="T:System.Collections.Generic.List`1"></see>
/// from an <see cref="T:System.Collections.Generic.IEnumerable`1"></see>.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <returns>An instance of <see cref="IProviderObservable{List}"/>.</returns>
public static IProviderObservable <List <TSource> > ToList <TSource>(
this IProviderObservable <IEnumerable <TSource> > observable) =>
observable.Map(s => s.ToList());
/// <summary>
/// <para>
/// Returns a new query where the change tracker will not track any of the entities
/// that are returned. If the entity instances are modified, this will not be
/// detected by the change tracker and
/// <see cref="M:Microsoft.EntityFrameworkCore.DbContext.SaveChanges" /> will not
/// persist those changes to the database.
/// </para>
/// <para>
/// Disabling change tracking is useful for read-only scenarios because it avoids
/// the overhead of setting up change tracking for each entity instance. You should
/// not disable change tracking if you want to manipulate entity instances and
/// persist those changes to the database using
/// <see cref="M:Microsoft.EntityFrameworkCore.DbContext.SaveChanges" />.
/// </para>
/// <para>
/// Identity resolution will still be performed to ensure that all occurrences of
/// an entity with a given key in the result set are represented by the same entity
/// instance.
/// </para>
/// <para>
/// The default tracking behavior for queries can be controlled by
/// <see cref="P:Microsoft.EntityFrameworkCore.ChangeTracking.ChangeTracker.QueryTrackingBehavior" />.
/// </para>
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <IQueryable <TSource> > AsNoTracking <TSource>(
this IProviderObservable <IQueryable <TSource> > observable)
where TSource : class =>
observable.Map(s => s.AsNoTracking());
/// <summary>
/// Filters a sequence of values based on a predicate.
/// Each element's index is used in the logic of the predicate function.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="predicate">
/// A function to test each element for a condition; the second
/// parameter of the function represents the index of the element in the source sequence.
/// </param>
/// <returns>An instance of <see cref="IProviderObservable{IQueryable}"/>.</returns>
public static IProviderObservable <IQueryable <TSource> > Where <TSource>(
this IProviderObservable <IQueryable <TSource> > observable,
Expression <Func <TSource, int, bool> > predicate) =>
observable.Map(s => s.Where(predicate));
/// <summary>
/// Sorts the elements of a sequence in ascending order by using a specified comparer.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="keySelector">A function to extract a key from an element.</param>
/// <param name="comparer">
/// An <see cref="T:System.Collections.Generic.IComparer`1"></see> to compare keys.
/// </param>
/// <returns>An instance of <see cref="IProviderObservable{IOrderedQueryable}"/>.</returns>
public static IProviderObservable <IOrderedQueryable <TSource> > OrderBy <TSource, TKey>(
this IProviderObservable <IQueryable <TSource> > observable,
Expression <Func <TSource, TKey> > keySelector,
IComparer <TKey> comparer) =>
observable.Map(s => s.OrderBy(keySelector, comparer));
/// <summary>
/// Performs a subsequent ordering of the elements in a sequence
/// in ascending order according to a key.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="keySelector">A function to extract a key from an element.</param>
/// <returns>An instance of <see cref="IProviderObservable{IOrderedQueryable}"/>.</returns>
public static IProviderObservable <IOrderedQueryable <TSource> > ThenBy <TSource, TKey>(
this IProviderObservable <IOrderedQueryable <TSource> > observable,
Expression <Func <TSource, TKey> > keySelector) =>
observable.Map(s => s.ThenBy(keySelector));
/// <summary>
/// Emits the only element of a sequence, and throws an exception
/// if there is not exactly one element in the sequence.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> Single <TSource>(
this IProviderObservable <IQueryable <TSource> > observable) =>
observable.Map(s => s.Single());
/// <summary>
/// Sorts the elements of a sequence in descending order according to a key.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="keySelector">A function to extract a key from an element.</param>
/// <returns>An instance of <see cref="IProviderObservable{IOrderedQueryable}"/>.</returns>
public static IProviderObservable <IOrderedQueryable <TSource> > OrderByDescending <TSource, TKey>(
this IProviderObservable <IQueryable <TSource> > observable,
Expression <Func <TSource, TKey> > keySelector) =>
observable.Map(s => s.OrderByDescending(keySelector));
/// <summary>
/// Performs a subsequent ordering of the elements in a sequence
/// in descending order by using a specified comparer.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="keySelector">A function to extract a key from an element.</param>
/// <param name="comparer">
/// An <see cref="T:System.Collections.Generic.IComparer`1"></see> to compare keys.
/// </param>
/// <returns>An instance of <see cref="IProviderObservable{IOrderedQueryable}"/>.</returns>
public static IProviderObservable <IOrderedQueryable <TSource> > ThenByDescending <TSource, TKey>(
this IProviderObservable <IOrderedQueryable <TSource> > observable,
Expression <Func <TSource, TKey> > keySelector,
IComparer <TKey> comparer) =>
observable.Map(s => s.ThenByDescending(keySelector, comparer));
