Creates a Source<TOut, TMat> that is materialized to an IActorRef which points to an Actor created according to the passed in Props. Actor created by the Props must be ActorPublisher<T>.

Declaration

public static Source<T, IActorRef> ActorPublisher<T>(Props props)

Parameters

Type	Name	Description
Props	props	TBD

Returns

Type	Description
Source<T, IActorRef>	TBD

Type Parameters

Name	Description
T	TBD

Exceptions

Type	Condition
ArgumentException	This exception is thrown when the specified actor `props` is not of type ActorPublisher<T>.

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ActorRef<T>(Int32, OverflowStrategy)

Creates a Source<TOut, TMat> that is materialized as an IActorRef. Messages sent to this actor will be emitted to the stream if there is demand from downstream, otherwise they will be buffered until request for demand is received.

Depending on the defined OverflowStrategy it might drop elements if there is no space available in the buffer.

The strategy Backpressure is not supported, and an IllegalArgument("Backpressure overflowStrategy not supported") will be thrown if it is passed as argument.

The buffer can be disabled by using bufferSize of 0 and then received messages are dropped if there is no demand from downstream. When bufferSize is 0 the overflowStrategy does not matter. An async boundary is added after this Source; as such, it is never safe to assume the downstream will always generate demand.

The stream can be completed successfully by sending the actor reference a Status.Success message (whose content will be ignored) in which case already buffered elements will be signaled before signaling completion, or by sending PoisonPill in which case completion will be signaled immediately.

The stream can be completed with failure by sending a Status.Failure to the actor reference. In case the Actor is still draining its internal buffer (after having received a Status.Success) before signaling completion and it receives a Status.Failure, the failure will be signaled downstream immediately (instead of the completion signal).

Note that terminating the actor without first completing it, either with a success or a failure, will prevent the actor triggering downstream completion and the stream will continue to run even though the source actor is dead. Therefore you should not attempt to manually terminate the actor such as with a PoisonPill.

The actor will be stopped when the stream is completed, failed or canceled from downstream, i.e. you can watch it to get notified when that happens.

Declaration

public static Source<T, IActorRef> ActorRef<T>(int bufferSize, OverflowStrategy overflowStrategy)

Parameters

Type	Name	Description
Int32	bufferSize	The size of the buffer in element count
OverflowStrategy	overflowStrategy	Strategy that is used when incoming elements cannot fit inside the buffer

Returns

Type	Description
Source<T, IActorRef>	TBD

Type Parameters

Name	Description
T	TBD

Exceptions

Type	Condition
ArgumentException	This exception is thrown when the specified `bufferSize` is less than zero.
NotSupportedException	This exception is thrown when the specified `overflowStrategy` is of type Backpressure.

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AsSubscriber<T>()

Creates a Source<TOut, TMat> that is materialized as a Reactive.Streams.ISubscriber<T>

Declaration

public static Source<T, ISubscriber<T>> AsSubscriber<T>()

Returns

Type	Description
Source<T, Reactive.Streams.ISubscriber<T>>	TBD

Type Parameters

Name	Description
T	TBD

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Channel<T>(Int32, Boolean, BoundedChannelFullMode)

Creates a Source that materializes a System.Threading.Channels.ChannelWriter<T> that may be used to write items to the stream.

This works similarly to Queue<T>(Int32, OverflowStrategy), The main difference being that you are allowed to have multiple Writes in flight. Allowing multiple writes makes Multi-producer scenarios easier but is still an important semantic difference.

Declaration

public static Source<T, ChannelWriter<T>> Channel<T>(int bufferSize, bool singleWriter = false, BoundedChannelFullMode fullMode = BoundedChannelFullMode.Wait)

Parameters

Type	Name	Description
Int32	bufferSize	The size of the channel's buffer
Boolean	singleWriter	If true, expects only one writer
System.Threading.Channels.BoundedChannelFullMode	fullMode	How the channel behaves when full

Returns

Type	Description
Source<T, System.Threading.Channels.ChannelWriter<T>>

Type Parameters

Name	Description
T

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ChannelReader<T>(ChannelReader<T>)

Declaration

public static Source<T, NotUsed> ChannelReader<T>(ChannelReader<T> channelReader)

Parameters

Type	Name	Description
System.Threading.Channels.ChannelReader<T>	channelReader

Returns

Type	Description
Source<T, NotUsed>

Type Parameters

Name	Description
T

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Combine<T, TOut2>(Source<T, NotUsed>, Source<T, NotUsed>, Func<Int32, IGraph<UniformFanInShape<T, TOut2>, NotUsed>>, Source<T, NotUsed>[])

Combines several sources with fun-in strategy like Merge<TIn, TOut> or Concat<TIn, TOut> and returns Source<TOut, TMat>.

Declaration

public static Source<TOut2, NotUsed> Combine<T, TOut2>(Source<T, NotUsed> first, Source<T, NotUsed> second, Func<int, IGraph<UniformFanInShape<T, TOut2>, NotUsed>> strategy, params Source<T, NotUsed>[] rest)

Parameters

Type	Name	Description
Source<T, NotUsed>	first	TBD
Source<T, NotUsed>	second	TBD
Func<Int32, IGraph<UniformFanInShape<T, TOut2>, NotUsed>>	strategy	TBD
Source<T, NotUsed>[]	rest	TBD

Returns

Type	Description
Source<TOut2, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD
TOut2	TBD

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CombineMaterialized<T, TOut2, TMat1, TMat2, TMatOut>(Source<T, TMat1>, Source<T, TMat2>, Func<Int32, IGraph<UniformFanInShape<T, TOut2>, NotUsed>>, Func<TMat1, TMat2, TMatOut>)

Combines two sources with fan-in strategy like Merge<TIn, TOut> or Concat<TIn, TOut> and returns Source<TOut, TMat> with a materialized value.

Declaration

public static Source<TOut2, TMatOut> CombineMaterialized<T, TOut2, TMat1, TMat2, TMatOut>(Source<T, TMat1> first, Source<T, TMat2> second, Func<int, IGraph<UniformFanInShape<T, TOut2>, NotUsed>> strategy, Func<TMat1, TMat2, TMatOut> combineMaterializers)

Parameters

Type	Name	Description
Source<T, TMat1>	first	TBD
Source<T, TMat2>	second	TBD
Func<Int32, IGraph<UniformFanInShape<T, TOut2>, NotUsed>>	strategy	TBD
Func<TMat1, TMat2, TMatOut>	combineMaterializers	TBD

Returns

Type	Description
Source<TOut2, TMatOut>	TBD

Type Parameters

Name	Description
T	TBD
TOut2	TBD
TMat1	TBD
TMat2	TBD
TMatOut	TBD

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Cycle<T>(Func<IEnumerator<T>>)

Create Source<TOut, TMat> that will continually produce given elements in specified order. Start a new cycled Source<TOut, TMat> from the given elements. The producer stream of elements will continue infinitely by repeating the sequence of elements provided by function parameter.

Declaration

public static Source<T, NotUsed> Cycle<T>(Func<IEnumerator<T>> enumeratorFactory)

Parameters

Type	Name	Description
Func<IEnumerator<T>>	enumeratorFactory	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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Empty<T>()

A Source<TOut, TMat> with no elements, i.e. an empty stream that is completed immediately for every connected Sink<TIn, TMat>.

Declaration

public static Source<T, NotUsed> Empty<T>()

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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Failed<T>(Exception)

Create a Source<TOut, TMat> that immediately ends the stream with the cause error to every connected Sink<TIn, TMat>.

Declaration

public static Source<T, NotUsed> Failed<T>(Exception cause)

Parameters

Type	Name	Description
Exception	cause	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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From<T>(IEnumerable<T>)

Helper to create Source<TOut, TMat> from IEnumerable<T>. Example usage: Source.From(Enumerable.Range(1, 10))

Starts a new Source<TOut, TMat> from the given IEnumerable<T>. This is like starting from an Enumerator, but every Subscriber directly attached to the Publisher of this stream will see an individual flow of elements (always starting from the beginning) regardless of when they subscribed.

Declaration

public static Source<T, NotUsed> From<T>(IEnumerable<T> enumerable)

Parameters

Type	Name	Description
IEnumerable<T>	enumerable	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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From<T>(Func<IAsyncEnumerable<T>>)

Helper to create Source<TOut, TMat> from System.Collections.Generic.IAsyncEnumerable<T>. Example usage: Source.From(Enumerable.Range(1, 10))

Starts a new Source<TOut, TMat> from the given System.Collections.Generic.IAsyncEnumerable<T>. This is like starting from an Enumerator, but every Subscriber directly attached to the Publisher of this stream will see an individual flow of elements (always starting from the beginning) regardless of when they subscribed.

Declaration

public static Source<T, NotUsed> From<T>(Func<IAsyncEnumerable<T>> asyncEnumerable)

Parameters

Type	Name	Description
Func<System.Collections.Generic.IAsyncEnumerable<T>>	asyncEnumerable

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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FromEnumerator<T>(Func<IEnumerator<T>>)

Helper to create Source<TOut, TMat> from IEnumerator<T>. Example usage: Source.FromEnumerator(() => Enumerable.Range(1, 10))

Start a new Source<TOut, TMat> from the given function that produces an IEnumerable<T>. The produced stream of elements will continue until the enumerator runs empty or fails during evaluation of the IEnumerator<T>.MoveNext method. Elements are pulled out of the enumerator in accordance with the demand coming from the downstream transformation steps.

Declaration

public static Source<T, NotUsed> FromEnumerator<T>(Func<IEnumerator<T>> enumeratorFactory)

Parameters

Type	Name	Description
Func<IEnumerator<T>>	enumeratorFactory	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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FromEvent<T>(Action<EventHandler<T>>, Action<EventHandler<T>>, Int32, OverflowStrategy)

Start a new Source<TOut, TMat> attached to a .NET event. In case when event will be triggered faster, than a downstream is able to consume incoming events, a buffering will occur. It can be configured via optional maxBufferCapacity and overflowStrategy parameters.

Declaration

public static Source<T, NotUsed> FromEvent<T>(Action<EventHandler<T>> addHandler, Action<EventHandler<T>> removeHandler, int maxBufferCapacity = 128, OverflowStrategy overflowStrategy = OverflowStrategy.DropHead)

Parameters

Type	Name	Description
Action<EventHandler<T>>	addHandler	Action used to attach the given event handler to the underlying .NET event.
Action<EventHandler<T>>	removeHandler	Action used to detach the given event handler to the underlying .NET event.
Int32	maxBufferCapacity	Maximum size of the buffer, used in situation when amount of emitted events is higher than current processing capabilities of the downstream.
OverflowStrategy	overflowStrategy	Overflow strategy used, when buffer (size specified by `maxBufferCapacity`) has been overflown.

Returns

Type	Description
Source<T, NotUsed>

Type Parameters

Name	Description
T	Type of the event args produced as source events.

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FromEvent<TDelegate, T>(Func<Action<T>, TDelegate>, Action<TDelegate>, Action<TDelegate>, Int32, OverflowStrategy)

Declaration

public static Source<T, NotUsed> FromEvent<TDelegate, T>(Func<Action<T>, TDelegate> conversion, Action<TDelegate> addHandler, Action<TDelegate> removeHandler, int maxBufferCapacity = 128, OverflowStrategy overflowStrategy = OverflowStrategy.DropHead)

Parameters

Type	Name	Description
Func<Action<T>, TDelegate>	conversion	A function used to convert provided event handler into a delegate compatible with an underlying .NET event type.
Action<TDelegate>	addHandler	Action used to attach the given event handler to the underlying .NET event.
Action<TDelegate>	removeHandler	Action used to detach the given event handler to the underlying .NET event.
Int32	maxBufferCapacity	Maximum size of the buffer, used in situation when amount of emitted events is higher than current processing capabilities of the downstream.
OverflowStrategy	overflowStrategy	Overflow strategy used, when buffer (size specified by `maxBufferCapacity`) has been overflown.

Returns

Type	Description
Source<T, NotUsed>

Type Parameters

Name	Description
TDelegate	Delegate type used to attach current source.
T	Type of the event args produced as source events.

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FromGraph<T, TMat>(IGraph<SourceShape<T>, TMat>)

A graph with the shape of a source logically is a source, this method makes it so also in type.

Declaration

public static Source<T, TMat> FromGraph<T, TMat>(IGraph<SourceShape<T>, TMat> source)

Parameters

Type	Name	Description
IGraph<SourceShape<T>, TMat>	source	TBD

Returns

Type	Description
Source<T, TMat>	TBD

Type Parameters

Name	Description
T	TBD
TMat	TBD

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FromObservable<T>(IObservable<T>, Int32, OverflowStrategy)

Start a new Source<TOut, TMat> attached to an existing IObservable<T>. In case when upstream (an observable) is producing events in a faster pace, than downstream is able to consume them, a buffering will occur. It can be configured via optional maxBufferCapacity and overflowStrategy parameters.

Declaration

public static Source<T, NotUsed> FromObservable<T>(IObservable<T> observable, int maxBufferCapacity = 128, OverflowStrategy overflowStrategy = OverflowStrategy.DropHead)

Parameters

Type	Name	Description
IObservable<T>	observable	An IObservable<T> to which current source will be subscribed.
Int32	maxBufferCapacity	Maximum size of the buffer, used in situation when amount of emitted events is higher than current processing capabilities of the downstream.
OverflowStrategy	overflowStrategy	Overflow strategy used, when buffer (size specified by `maxBufferCapacity`) has been overflown.

Returns

Type	Description
Source<T, NotUsed>

Type Parameters

Name	Description
T	Type of the event args produced as source events.

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FromPublisher<T>(IPublisher<T>)

Helper to create Source<TOut, TMat> from Reactive.Streams.IPublisher<T>.

Construct a transformation starting with given publisher. The transformation steps are executed by a series of Reactive.Streams.IProcessor`2 instances that mediate the flow of elements downstream and the propagation of back-pressure upstream.

Declaration

public static Source<T, NotUsed> FromPublisher<T>(IPublisher<T> publisher)

Parameters

Type	Name	Description
Reactive.Streams.IPublisher<T>	publisher	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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FromTask<T>(Task<T>)

Start a new Source<TOut, TMat> from the given Task<TResult>. The stream will consist of one element when the Task<TResult> is completed with a successful value, which may happen before or after materializing the IFlow<TOut, TMat>. The stream terminates with a failure if the task is completed with a failure.

Declaration

public static Source<T, NotUsed> FromTask<T>(Task<T> task)

Parameters

Type	Name	Description
Task<T>	task	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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FromTaskSource<T, M>(Task<Source<T, M>>)

Streams the elements of the given future source once it successfully completes. If the Task<TResult> fails the stream is failed with the exception from the future. If downstream cancels before the stream completes the materialized Task<TResult> will be failed with a StreamDetachedException

Declaration

public static Source<T, Task<M>> FromTaskSource<T, M>(Task<Source<T, M>> task)

Parameters

Type	Name	Description
Task<Source<T, M>>	task	TBD

Returns

Type	Description
Source<T, Task<M>>	TBD

Type Parameters

Name	Description
T	TBD
M	TBD

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Lazily<TOut, TMat>(Func<Source<TOut, TMat>>)

Creates a Source<TOut, TMat> that is not materialized until there is downstream demand, when the source gets materialized the materialized task is completed with its value, if downstream cancels or fails without any demand the create factory is never called and the materialized Task<TResult> is failed.

Declaration

public static Source<TOut, Task<TMat>> Lazily<TOut, TMat>(Func<Source<TOut, TMat>> create)

Parameters

Type	Name	Description
Func<Source<TOut, TMat>>	create

Returns

Type	Description
Source<TOut, Task<TMat>>

Type Parameters

Name	Description
TOut
TMat

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Maybe<T>()

Create a Source<TOut, TMat> which materializes a TaskCompletionSource<TResult> which controls what element will be emitted by the Source. If the materialized promise is completed with a Some, that value will be produced downstream, followed by completion. If the materialized promise is completed with a None, no value will be produced downstream and completion will be signaled immediately. If the materialized promise is completed with a failure, then the returned source will terminate with that error. If the downstream of this source cancels before the promise has been completed, then the promise will be completed with None.

Declaration

public static Source<T, TaskCompletionSource<T>> Maybe<T>()

Returns

Type	Description
Source<T, TaskCompletionSource<T>>	TBD

Type Parameters

Name	Description
T	TBD

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Never<T>()

Never emits any elements, never completes and never fails. This stream could be useful in tests.

Declaration

public static Source<T, NotUsed> Never<T>()

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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Queue<T>(Int32, OverflowStrategy)

Creates a Source<TOut, TMat> that is materialized as an ISourceQueueWithComplete<T>. You can push elements to the queue and they will be emitted to the stream if there is demand from downstream, otherwise they will be buffered until request for demand is received.

Depending on the defined OverflowStrategy it might drop elements if there is no space available in the buffer.

Acknowledgement mechanism is available. ISourceQueueWithComplete<T>.OfferAsync returns Task which completes with QueueOfferResult.Enqueued if element was added to buffer or sent downstream. It completes with QueueOfferResult.Dropped if element was dropped. Can also complete with QueueOfferResult.Failure - when stream failed or QueueOfferResult.QueueClosed when downstream is completed.

The strategy Backpressure will not complete ISourceQueueWithComplete<T>.OfferAsync when buffer is full.

The buffer can be disabled by using bufferSize of 0 and then received messages will wait for downstream demand unless there is another message waiting for downstream demand, in that case offer result will be completed according to the overflowStrategy.

Declaration

public static Source<T, ISourceQueueWithComplete<T>> Queue<T>(int bufferSize, OverflowStrategy overflowStrategy)

Parameters

Type	Name	Description
Int32	bufferSize	The size of the buffer in element count
OverflowStrategy	overflowStrategy	Strategy that is used when incoming elements cannot fit inside the buffer

Returns

Type	Description
Source<T, ISourceQueueWithComplete<T>>	TBD

Type Parameters

Name	Description
T	TBD

Exceptions

Type	Condition
ArgumentException	This exception is thrown when the specified `bufferSize` is less than zero.

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Repeat<T>(T)

Create a Source<TOut, TMat> that will continually emit the given element.

Declaration

public static Source<T, NotUsed> Repeat<T>(T element)

Parameters

Type	Name	Description
T	element	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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Setup<T, TMat>(Func<ActorMaterializer, Attributes, Source<T, TMat>>)

Defers the creation of a Source until materialization. The factory function exposes ActorMaterializer which is going to be used during materialization and Attributes of the Source returned by this method.

Declaration

public static Source<T, Task<TMat>> Setup<T, TMat>(Func<ActorMaterializer, Attributes, Source<T, TMat>> factory)

Parameters

Type	Name	Description
Func<ActorMaterializer, Attributes, Source<T, TMat>>	factory	TBD

Returns

Type	Description
Source<T, Task<TMat>>	TBD

Type Parameters

Name	Description
T	TBD
TMat	TBD

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Shape<T>(String)

TBD

Declaration

public static SourceShape<T> Shape<T>(string name)

Parameters

Type	Name	Description
String	name	TBD

Returns

Type	Description
SourceShape<T>	TBD

Type Parameters

Name	Description
T	TBD

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Single<T>(T)

Create a Source<TOut, TMat> with one element. Every connected Sink<TIn, TMat> of this stream will see an individual stream consisting of one element.

Declaration

public static Source<T, NotUsed> Single<T>(T element)

Parameters

Type	Name	Description
T	element	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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Tick<T>(TimeSpan, TimeSpan, T)

Elements are emitted periodically with the specified interval. The tick element will be delivered to downstream consumers that has requested any elements. If a consumer has not requested any elements at the point in time when the tick element is produced it will not receive that tick element later. It will receive new tick elements as soon as it has requested more elements.

Declaration

public static Source<T, ICancelable> Tick<T>(TimeSpan initialDelay, TimeSpan interval, T tick)

Parameters

Type	Name	Description
TimeSpan	initialDelay	TBD
TimeSpan	interval	TBD
T	tick	TBD

Returns

Type	Description
Source<T, ICancelable>	TBD

Type Parameters

Name	Description
T	TBD

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Unfold<TState, TElem>(TState, Func<TState, Option<(TState, TElem)>>)

Create a Source<TOut, TMat> that will unfold a value of type TState into a pair of the next state TState and output elements of type TElem.

Declaration

public static Source<TElem, NotUsed> Unfold<TState, TElem>(TState state, Func<TState, Option<(TState, TElem)>> unfold)

Parameters

Type	Name	Description
TState	state	TBD
Func<TState, Option<System.ValueTuple<TState, TElem>>>	unfold	TBD

Returns

Type	Description
Source<TElem, NotUsed>	TBD

Type Parameters

Name	Description
TState	TBD
TElem	TBD

Examples

For example, all the Fibonacci numbers under 10M:

  Source.unfold(0 → 1) {
   case (a, _) if a > 10000000 ⇒ None
   case (a, b) ⇒ Some((b → (a + b)) → a)
  }

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UnfoldAsync<TState, TElem>(TState, Func<TState, Task<Option<(TState, TElem)>>>)

Same as Unfold<TState, TElem>(TState, Func<TState, Option<(TState, TElem)>>), but uses an async function to generate the next state-element tuple.

Declaration

public static Source<TElem, NotUsed> UnfoldAsync<TState, TElem>(TState state, Func<TState, Task<Option<(TState, TElem)>>> unfoldAsync)

Parameters

Type	Name	Description
TState	state	TBD
Func<TState, Task<Option<System.ValueTuple<TState, TElem>>>>	unfoldAsync	TBD

Returns

Type	Description
Source<TElem, NotUsed>	TBD

Type Parameters

Name	Description
TState	TBD
TElem	TBD

Examples

For example, all the Fibonacci numbers under 10M:

Source.unfoldAsync(0 → 1) {
 case (a, _) if a > 10000000 ⇒ Future.successful(None)
 case (a, b) ⇒ Future{
   Thread.sleep(1000)
   Some((b → (a + b)) → a)
 }
}

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UnfoldInfinite<TState, TElem>(TState, Func<TState, (TState, TElem)>)

Simpler Unfold<TState, TElem>(TState, Func<TState, Option<(TState, TElem)>>), for infinite sequences.

Declaration

public static Source<TElem, NotUsed> UnfoldInfinite<TState, TElem>(TState state, Func<TState, (TState, TElem)> unfold)

Parameters

Type	Name	Description
TState	state	TBD
Func<TState, System.ValueTuple<TState, TElem>>	unfold	TBD

Returns

Type	Description
Source<TElem, NotUsed>	TBD

Type Parameters

Name	Description
TState	TBD
TElem	TBD

Examples

{{{
  Source.unfoldInf(0 → 1) {
   case (a, b) ⇒ (b → (a + b)) → a
  }
}}}

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UnfoldResource<T, TSource>(Func<TSource>, Func<TSource, Option<T>>, Action<TSource>)

Start a new Source<TOut, TMat> from some resource which can be opened, read and closed. Interaction with resource happens in a blocking way.

Example: {{{ Source.unfoldResource( () => new BufferedReader(new FileReader("...")), reader => Option(reader.readLine()), reader => reader.close()) }}}

You can use the supervision strategy to handle exceptions for read function. All exceptions thrown by create or close will fail the stream.

Restart supervision strategy will close and create blocking IO again. Default strategy is Stop which means that stream will be terminated on error in read function by default.

You can configure the default dispatcher for this Source by changing the akka.stream.blocking-io-dispatcher or set it for a given Source by using CreateDispatcher(String).

Adheres to the ActorAttributes.SupervisionStrategy attribute.

Declaration

public static Source<T, NotUsed> UnfoldResource<T, TSource>(Func<TSource> create, Func<TSource, Option<T>> read, Action<TSource> close)

Parameters

Type	Name	Description
Func<TSource>	create	function that is called on stream start and creates/opens resource.
Func<TSource, Option<T>>	read	function that reads data from opened resource. It is called each time backpressure signal is received. Stream calls close and completes when `read` returns None.
Action<TSource>	close	TBD

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD
TSource	TBD

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UnfoldResourceAsync<T, TSource>(Func<Task<TSource>>, Func<TSource, Task<Option<T>>>, Func<TSource, Task<Done>>)

Start a new Source<TOut, TMat> from some resource which can be opened, read and closed. It's similar to UnfoldResource<T, TSource>(Func<TSource>, Func<TSource, Option<T>>, Action<TSource>) but takes functions that return Tasks instead of plain values.

You can use the supervision strategy to handle exceptions for read function or failures of produced Tasks. All exceptions thrown by create or close as well as fails of returned futures will fail the stream.

Restart supervision strategy will close and create resource .Default strategy is Stop which means that stream will be terminated on error in read function (or task) by default.

You can configure the default dispatcher for this Source by changing the akka.stream.blocking-io-dispatcher or set it for a given Source by using CreateDispatcher(String).

Adheres to the ActorAttributes.SupervisionStrategy attribute.

Declaration

public static Source<T, NotUsed> UnfoldResourceAsync<T, TSource>(Func<Task<TSource>> create, Func<TSource, Task<Option<T>>> read, Func<TSource, Task<Done>> close)

Parameters

Type	Name	Description
Func<Task<TSource>>	create	function that is called on stream start and creates/opens resource.
Func<TSource, Task<Option<T>>>	read	function that reads data from opened resource. It is called each time backpressure signal is received. Stream calls close and completes when Task from read function returns None.
Func<TSource, Task<Done>>	close	function that closes resource

Returns

Type	Description
Source<T, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD
TSource	TBD

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ZipN<T>(IEnumerable<Source<T, NotUsed>>)

Combines the elements of multiple streams into a stream of lists.

Declaration

public static Source<IImmutableList<T>, NotUsed> ZipN<T>(IEnumerable<Source<T, NotUsed>> sources)

Parameters

Type	Name	Description
IEnumerable<Source<T, NotUsed>>	sources	TBD

Returns

Type	Description
Source<System.Collections.Immutable.IImmutableList<T>, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD

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ZipWithN<T, TOut2>(Func<IImmutableList<T>, TOut2>, IEnumerable<Source<T, NotUsed>>)

Combines the elements of multiple streams into a stream of sequences using a combiner function.

Declaration

public static Source<TOut2, NotUsed> ZipWithN<T, TOut2>(Func<IImmutableList<T>, TOut2> zipper, IEnumerable<Source<T, NotUsed>> sources)

Parameters

Type	Name	Description
Func<System.Collections.Immutable.IImmutableList<T>, TOut2>	zipper	TBD
IEnumerable<Source<T, NotUsed>>	sources	TBD

Returns

Type	Description
Source<TOut2, NotUsed>	TBD

Type Parameters

Name	Description
T	TBD
TOut2	TBD