Instance Methodswift-nio 2.72.0NIOCore

whenFailureBlocking(onto:_:)

Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has a failure result. The observer callback is permitted to block.

EventLoopFuture.swift:1731

@preconcurrency func whenFailureBlocking(onto queue: DispatchQueue, _ callbackMayBlock: @escaping (Error) -> Void)

Mangled symbol

s7NIOCore15EventLoopFutureC19whenFailureBlocking4onto_y8Dispatch0I5QueueC_ys5Error_pctFWhat are these?

FNV24: [8IR1I]

Parameters

onto: the DispatchQueue on which the blocking IO / task specified by callbackMayBlock is scheduled.
callbackMayBlock: The callback that is called with the failed result of the EventLoopFuture.

An observer callback cannot return a value, meaning that this function cannot be chained from. If you are attempting to create a computation pipeline, consider recover or flatMapError. If you find yourself passing the results from this EventLoopFuture to a new EventLoopPromise in the body of this function, consider using cascade instead.

Other members in extension

Type members

static func andAllComplete([EventLoopFuture<Value>], on: EventLoop) -> EventLoopFuture<Void>
Returns a new EventLoopFuture that succeeds when all of the provided EventLoopFutures complete.
static func andAllComplete([EventLoopFuture<Value>], promise: EventLoopPromise<Void>)
Completes a promise when all of the provided EventLoopFutures have completed.
static func andAllSucceed([EventLoopFuture<Value>], on: EventLoop) -> EventLoopFuture<Void>
Returns a new EventLoopFuture that succeeds only if all of the provided futures succeed.
static func andAllSucceed([EventLoopFuture<Value>], promise: EventLoopPromise<Void>)
Succeeds the promise if all of the provided futures succeed. If any of the provided futures fail then the promise will be failed – even if some futures are yet to complete.
static func reduce<InputValue>(Value, [EventLoopFuture<InputValue>], on: EventLoop, @escaping (Value, InputValue) -> Value) -> EventLoopFuture<Value>
Returns a new EventLoopFuture that fires only when all the provided futures complete. The new EventLoopFuture contains the result of reducing the initialResult with the values of the [EventLoopFuture<NewValue>].
static func reduce<InputValue>(into: Value, [EventLoopFuture<InputValue>], on: EventLoop, @escaping (inout Value, InputValue) -> Void) -> EventLoopFuture<Value>
Returns a new EventLoopFuture that fires only when all the provided futures complete. The new EventLoopFuture contains the result of combining the initialResult with the values of the [EventLoopFuture<NewValue>]. This function is analogous to the standard library’s reduce(into:), which does not make copies of the result type for each EventLoopFuture.
static func whenAllComplete([EventLoopFuture<Value>], on: EventLoop) -> EventLoopFuture<[Result<Value, Error>]>
Returns a new EventLoopFuture that succeeds when all of the provided EventLoopFutures complete. The new EventLoopFuture will contain an array of results, maintaining ordering for each of the EventLoopFutures.
static func whenAllComplete([EventLoopFuture<Value>], promise: EventLoopPromise<[Result<Value, Error>]>)
Completes a promise with the results of all provided EventLoopFutures.
static func whenAllSucceed([EventLoopFuture<Value>], on: EventLoop) -> EventLoopFuture<[Value]>
Returns a new EventLoopFuture that succeeds only if all of the provided futures succeed. The new EventLoopFuture will contain all of the values fulfilled by the futures.
static func whenAllSucceed([EventLoopFuture<Value>], promise: EventLoopPromise<[Value]>)
Completes the promise with the values of all futures if all provided futures succeed. If any of the provided futures fail then promise will be failed.
static func == (lhs: EventLoopFuture, rhs: EventLoopFuture) -> Bool

Instance members

let eventLoop: EventLoop
The EventLoop which is tied to the EventLoopFuture and is used to notify all registered callbacks.
func always(@escaping (Result<Value, Error>) -> Void) -> EventLoopFuture<Value>
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has any result.
func and<OtherValue>(EventLoopFuture<OtherValue>) -> EventLoopFuture<(Value, OtherValue)>
Return a new EventLoopFuture that succeeds when this “and” another provided EventLoopFuture both succeed. It then provides the pair of results. If either one fails, the combined EventLoopFuture will fail with the first error encountered.
func and<OtherValue>(value: OtherValue) -> EventLoopFuture<(Value, OtherValue)>
Return a new EventLoopFuture that contains this “and” another value. This is just syntactic sugar for future.and(loop.makeSucceedFuture(value)).
func assertFailure(file: StaticString, line: UInt) -> EventLoopFuture<Value>
Attaches a callback to the EventLoopFuture that asserts the original future’s failure.
func assertSuccess(file: StaticString, line: UInt) -> EventLoopFuture<Value>
Attaches a callback to the EventLoopFuture that asserts the original future’s success.
func cascade(to: EventLoopPromise<Value>?)
Fulfills the given EventLoopPromise with the results from this EventLoopFuture.
func cascadeFailure<NewValue>(to: EventLoopPromise<NewValue>?)
Fails the given EventLoopPromise with the error from this EventLoopFuture if encountered.
func cascadeSuccess(to: EventLoopPromise<Value>?)
Fulfills the given EventLoopPromise only when this EventLoopFuture succeeds.
func flatMap<NewValue>(@escaping (Value) -> EventLoopFuture<NewValue>) -> EventLoopFuture<NewValue>
When the current EventLoopFuture<Value> is fulfilled, run the provided callback, which will provide a new EventLoopFuture.
func flatMapBlocking<NewValue>(onto: DispatchQueue, @escaping (Value) throws -> NewValue) -> EventLoopFuture<NewValue>
Chain an EventLoopFuture<NewValue> providing the result of a IO / task that may block. For example:
func flatMapError(@escaping (Error) -> EventLoopFuture<Value>) -> EventLoopFuture<Value>
When the current EventLoopFuture<Value> is in an error state, run the provided callback, which may recover from the error by returning an EventLoopFuture<NewValue>. The callback is intended to potentially recover from the error by returning a new EventLoopFuture that will eventually contain the recovered result.
func flatMapErrorThrowing(@escaping (Error) throws -> Value) -> EventLoopFuture<Value>
When the current EventLoopFuture<Value> is in an error state, run the provided callback, which may recover from the error and returns a new value of type Value. The provided callback may optionally throw, in which case the EventLoopFuture will be in a failed state with the new thrown error.
func flatMapErrorWithEventLoop(@escaping (Error, EventLoop) -> EventLoopFuture<Value>) -> EventLoopFuture<Value>
When the current EventLoopFuture<Value> is in an error state, run the provided callback, which may recover from the error by returning an EventLoopFuture<NewValue>. The callback is intended to potentially recover from the error by returning a new EventLoopFuture that will eventually contain the recovered result.
func flatMapResult<NewValue, SomeError>(@escaping (Value) -> Result<NewValue, SomeError>) -> EventLoopFuture<NewValue>
When the current EventLoopFuture<Value> is fulfilled, run the provided callback, which performs a synchronous computation and returns either a new value (of type NewValue) or an error depending on the Result returned by the closure.
func flatMapThrowing<NewValue>(@escaping (Value) throws -> NewValue) -> EventLoopFuture<NewValue>
When the current EventLoopFuture<Value> is fulfilled, run the provided callback, which performs a synchronous computation and returns a new value of type NewValue. The provided callback may optionally throw.
func flatMapWithEventLoop<NewValue>(@escaping (Value, EventLoop) -> EventLoopFuture<NewValue>) -> EventLoopFuture<NewValue>
When the current EventLoopFuture<Value> is fulfilled, run the provided callback, which will provide a new EventLoopFuture alongside the EventLoop associated with this future.
func fold<OtherValue>([EventLoopFuture<OtherValue>], with: @escaping (Value, OtherValue) -> EventLoopFuture<Value>) -> EventLoopFuture<Value>
Returns a new EventLoopFuture that fires only when this EventLoopFuture and all the provided futures complete. It then provides the result of folding the value of this EventLoopFuture with the values of all the provided futures.
func foldWithEventLoop<OtherValue>([EventLoopFuture<OtherValue>], with: @escaping (Value, OtherValue, EventLoop) -> EventLoopFuture<Value>) -> EventLoopFuture<Value>
Returns a new EventLoopFuture that fires only when this EventLoopFuture and all the provided futures complete. It then provides the result of folding the value of this EventLoopFuture with the values of all the provided futures.
func get() async throws -> Value
Get the value/error from an EventLoopFuture in an async context.
func hop(to: EventLoop) -> EventLoopFuture<Value>
Returns an EventLoopFuture that fires when this future completes, but executes its callbacks on the target event loop instead of the original one.
func map<NewValue>(@escaping (Value) -> (NewValue)) -> EventLoopFuture<NewValue>
When the current EventLoopFuture<Value> is fulfilled, run the provided callback, which performs a synchronous computation and returns a new value of type NewValue.
func preconditionFailure(file: StaticString, line: UInt) -> EventLoopFuture<Value>
Attaches a callback to the EventLoopFuture that preconditions the original future’s failure.
func preconditionSuccess(file: StaticString, line: UInt) -> EventLoopFuture<Value>
Attaches a callback to the EventLoopFuture that preconditions the original future’s success.
func recover(@escaping (Error) -> Value) -> EventLoopFuture<Value>
When the current EventLoopFuture<Value> is in an error state, run the provided callback, which can recover from the error and return a new value of type Value. The provided callback may not throw, so this function should be used when the error is always recoverable.
func unwrap<NewValue>(orElse: @escaping () -> NewValue) -> EventLoopFuture<NewValue>
Unwrap an EventLoopFuture where its type parameter is an Optional.
func unwrap<NewValue>(orError: Error) -> EventLoopFuture<NewValue>
Unwrap an EventLoopFuture where its type parameter is an Optional.
func unwrap<NewValue>(orReplace: NewValue) -> EventLoopFuture<NewValue>
Unwrap an EventLoopFuture where its type parameter is an Optional.
func wait(file: StaticString, line: UInt) throws -> Value
Wait for the resolution of this EventLoopFuture by blocking the current thread until it resolves.
func whenComplete(@escaping (Result<Value, Error>) -> Void)
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has any result.
func whenCompleteBlocking(onto: DispatchQueue, @escaping (Result<Value, Error>) -> Void)
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has any result. The observer callback is permitted to block.
func whenFailure(@escaping (Error) -> Void)
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has a failure result.
func whenSuccess(@escaping (Value) -> Void)
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has a success result.
func whenSuccessBlocking(onto: DispatchQueue, @escaping (Value) -> Void)
Adds an observer callback to this EventLoopFuture that is called when the EventLoopFuture has a success result. The observer callback is permitted to block.

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