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Web API AsyncApiActionInvoker

Overrides the standard Web API ApiControllerActionInvoker with one that works with controller actions return F# Async<'T> results.

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#r "System.Net.Http";;

open System
open System.Diagnostics.Contracts
open System.Net
open System.Net.Http
open System.Reflection
open System.Web.Http
open System.Web.Http.Controllers

type AsyncApiActionInvoker() =
    inherit Controllers.ApiControllerActionInvoker()

    static let (|Async|_|) (ty: Type) =
        if ty.IsGenericType && ty.GetGenericTypeDefinition() = typedefof<Async<_>> then
            Some (ty.GetGenericArguments().[0])
        else None

    static let asTaskMethod = typeof<AsyncApiActionInvoker>.GetMethod("StartAsTask", BindingFlags.NonPublic ||| BindingFlags.Static)
    static let voidResultConverter = VoidResultConverter()

    static member internal GetResultConverter<'T>(actionContext: HttpActionContext) : IActionResultConverter =
        let instanceType = typeof<'T>
        if instanceType <> null && instanceType.IsGenericParameter then
            raise <| InvalidOperationException()

        if instanceType = null || typeof<HttpResponseMessage>.IsAssignableFrom instanceType then
            actionContext.ActionDescriptor.ResultConverter
        elif instanceType = typeof<unit> then
            voidResultConverter :> _
        else new ValueResultConverter<'T>() :> _

    static member internal StartAsTask<'T>(actionContext: HttpActionContext, cancellationToken) =
        let resultConverter = AsyncApiActionInvoker.GetResultConverter<'T>(actionContext)
        let computation = async {
            let task =
                actionContext.ActionDescriptor.ExecuteAsync(
                    actionContext.ControllerContext,
                    actionContext.ActionArguments,
                    cancellationToken)
            let! result = Async.AwaitTask task
            let! (value: 'T) = unbox result
            return resultConverter.Convert(actionContext.ControllerContext, value) }
        Async.StartAsTask(computation, cancellationToken = cancellationToken)

    override this.InvokeActionAsync(actionContext, cancellationToken) =
        if actionContext = null then
            raise <| ArgumentNullException("actionContext")

        match actionContext.ActionDescriptor.ReturnType with
        | Async resultType ->
            let specialized = asTaskMethod.MakeGenericMethod(resultType)
            downcast specialized.Invoke(null, [| actionContext; cancellationToken |])
        | _ -> base.InvokeActionAsync(actionContext, cancellationToken)
namespace System
namespace System.Diagnostics
namespace System.Diagnostics.Contracts
namespace System.Net
namespace System.Net.Http
namespace System.Reflection
namespace System.Web
namespace System.Web.Http
namespace System.Web.Http.Controllers
Multiple items
type AsyncApiActionInvoker =
  inherit ApiControllerActionInvoker
  new : unit -> AsyncApiActionInvoker
  override InvokeActionAsync : actionContext:HttpActionContext * cancellationToken:CancellationToken -> Task<HttpResponseMessage>
  static member internal GetResultConverter : actionContext:HttpActionContext -> IActionResultConverter
  static member internal StartAsTask : actionContext:HttpActionContext * cancellationToken:CancellationToken -> Task<HttpResponseMessage>

Full name: Script.AsyncApiActionInvoker

--------------------
new : unit -> AsyncApiActionInvoker
Multiple items
type ApiControllerActionInvoker =
  new : unit -> ApiControllerActionInvoker
  member InvokeActionAsync : actionContext:HttpActionContext * cancellationToken:CancellationToken -> Task<HttpResponseMessage>

Full name: System.Web.Http.Controllers.ApiControllerActionInvoker

--------------------
ApiControllerActionInvoker() : unit
Multiple items
type Async
static member AsBeginEnd : computation:('Arg -> Async<'T>) -> ('Arg * AsyncCallback * obj -> IAsyncResult) * (IAsyncResult -> 'T) * (IAsyncResult -> unit)
static member AwaitEvent : event:IEvent<'Del,'T> * ?cancelAction:(unit -> unit) -> Async<'T> (requires delegate and 'Del :> Delegate)
static member AwaitIAsyncResult : iar:IAsyncResult * ?millisecondsTimeout:int -> Async<bool>
static member AwaitTask : task:Task<'T> -> Async<'T>
static member AwaitWaitHandle : waitHandle:WaitHandle * ?millisecondsTimeout:int -> Async<bool>
static member CancelDefaultToken : unit -> unit
static member Catch : computation:Async<'T> -> Async<Choice<'T,exn>>
static member FromBeginEnd : beginAction:(AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg:'Arg1 * beginAction:('Arg1 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * beginAction:('Arg1 * 'Arg2 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * arg3:'Arg3 * beginAction:('Arg1 * 'Arg2 * 'Arg3 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromContinuations : callback:(('T -> unit) * (exn -> unit) * (OperationCanceledException -> unit) -> unit) -> Async<'T>
static member Ignore : computation:Async<'T> -> Async<unit>
static member OnCancel : interruption:(unit -> unit) -> Async<IDisposable>
static member Parallel : computations:seq<Async<'T>> -> Async<'T []>
static member RunSynchronously : computation:Async<'T> * ?timeout:int * ?cancellationToken:CancellationToken -> 'T
static member Sleep : millisecondsDueTime:int -> Async<unit>
static member Start : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions * ?cancellationToken:CancellationToken -> Task<'T>
static member StartChild : computation:Async<'T> * ?millisecondsTimeout:int -> Async<Async<'T>>
static member StartChildAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions -> Async<Task<'T>>
static member StartImmediate : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartWithContinuations : computation:Async<'T> * continuation:('T -> unit) * exceptionContinuation:(exn -> unit) * cancellationContinuation:(OperationCanceledException -> unit) * ?cancellationToken:CancellationToken -> unit
static member SwitchToContext : syncContext:SynchronizationContext -> Async<unit>
static member SwitchToNewThread : unit -> Async<unit>
static member SwitchToThreadPool : unit -> Async<unit>
static member TryCancelled : computation:Async<'T> * compensation:(OperationCanceledException -> unit) -> Async<'T>
static member CancellationToken : Async<CancellationToken>
static member DefaultCancellationToken : CancellationToken

Full name: Microsoft.FSharp.Control.Async

--------------------
type Async<'T>

Full name: Microsoft.FSharp.Control.Async<_>
val ty : Type
type Type =
  inherit MemberInfo
  member Assembly : Assembly
  member AssemblyQualifiedName : string
  member Attributes : TypeAttributes
  member BaseType : Type
  member ContainsGenericParameters : bool
  member DeclaringMethod : MethodBase
  member DeclaringType : Type
  member Equals : o:obj -> bool + 1 overload
  member FindInterfaces : filter:TypeFilter * filterCriteria:obj -> Type[]
  member FindMembers : memberType:MemberTypes * bindingAttr:BindingFlags * filter:MemberFilter * filterCriteria:obj -> MemberInfo[]
  ...

Full name: System.Type
property Type.IsGenericType: bool
Type.GetGenericTypeDefinition() : Type
val typedefof<'T> : Type

Full name: Microsoft.FSharp.Core.Operators.typedefof
union case Option.Some: Value: 'T -> Option<'T>
Type.GetGenericArguments() : Type []
union case Option.None: Option<'T>
val asTaskMethod : MethodInfo
val typeof<'T> : Type

Full name: Microsoft.FSharp.Core.Operators.typeof
type BindingFlags =
  | Default = 0
  | IgnoreCase = 1
  | DeclaredOnly = 2
  | Instance = 4
  | Static = 8
  | Public = 16
  | NonPublic = 32
  | FlattenHierarchy = 64
  | InvokeMethod = 256
  | CreateInstance = 512
  ...

Full name: System.Reflection.BindingFlags
field BindingFlags.NonPublic = 32
field BindingFlags.Static = 8
val voidResultConverter : VoidResultConverter
Multiple items
type VoidResultConverter =
  new : unit -> VoidResultConverter
  member Convert : controllerContext:HttpControllerContext * actionResult:obj -> HttpResponseMessage

Full name: System.Web.Http.Controllers.VoidResultConverter

--------------------
VoidResultConverter() : unit
static member internal AsyncApiActionInvoker.GetResultConverter : actionContext:HttpActionContext -> IActionResultConverter

Full name: Script.AsyncApiActionInvoker.GetResultConverter
val actionContext : HttpActionContext
Multiple items
type HttpActionContext =
  new : unit -> HttpActionContext + 1 overload
  member ActionArguments : Dictionary<string, obj>
  member ActionDescriptor : HttpActionDescriptor with get, set
  member ControllerContext : HttpControllerContext with get, set
  member ModelState : ModelStateDictionary
  member Request : HttpRequestMessage
  member RequestContext : HttpRequestContext
  member Response : HttpResponseMessage with get, set

Full name: System.Web.Http.Controllers.HttpActionContext

--------------------
HttpActionContext() : unit
HttpActionContext(controllerContext: HttpControllerContext, actionDescriptor: HttpActionDescriptor) : unit
type IActionResultConverter =
  member Convert : controllerContext:HttpControllerContext * actionResult:obj -> HttpResponseMessage

Full name: System.Web.Http.Controllers.IActionResultConverter
val instanceType : Type
property Type.IsGenericParameter: bool
val raise : exn:Exception -> 'T

Full name: Microsoft.FSharp.Core.Operators.raise
Multiple items
type InvalidOperationException =
  inherit SystemException
  new : unit -> InvalidOperationException + 2 overloads

Full name: System.InvalidOperationException

--------------------
InvalidOperationException() : unit
InvalidOperationException(message: string) : unit
InvalidOperationException(message: string, innerException: exn) : unit
Multiple items
type HttpResponseMessage =
  new : unit -> HttpResponseMessage + 1 overload
  member Content : HttpContent with get, set
  member Dispose : unit -> unit
  member EnsureSuccessStatusCode : unit -> HttpResponseMessage
  member Headers : HttpResponseHeaders
  member IsSuccessStatusCode : bool
  member ReasonPhrase : string with get, set
  member RequestMessage : HttpRequestMessage with get, set
  member StatusCode : HttpStatusCode with get, set
  member ToString : unit -> string
  ...

Full name: System.Net.Http.HttpResponseMessage

--------------------
HttpResponseMessage() : unit
HttpResponseMessage(statusCode: HttpStatusCode) : unit
property HttpActionContext.ActionDescriptor: HttpActionDescriptor
property HttpActionDescriptor.ResultConverter: IActionResultConverter
type unit = Unit

Full name: Microsoft.FSharp.Core.unit
Multiple items
type ValueResultConverter<'T> =
  new : unit -> ValueResultConverter<'T>
  member Convert : controllerContext:HttpControllerContext * actionResult:obj -> HttpResponseMessage

Full name: System.Web.Http.Controllers.ValueResultConverter<_>

--------------------
ValueResultConverter() : unit
static member internal AsyncApiActionInvoker.StartAsTask : actionContext:HttpActionContext * cancellationToken:Threading.CancellationToken -> Threading.Tasks.Task<HttpResponseMessage>

Full name: Script.AsyncApiActionInvoker.StartAsTask
val cancellationToken : Threading.CancellationToken
val resultConverter : IActionResultConverter
static member internal AsyncApiActionInvoker.GetResultConverter : actionContext:HttpActionContext -> IActionResultConverter
val computation : Async<HttpResponseMessage>
val async : AsyncBuilder

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.async
val task : Threading.Tasks.Task<obj>
HttpActionDescriptor.ExecuteAsync(controllerContext: HttpControllerContext, arguments: Collections.Generic.IDictionary<string,obj>, cancellationToken: Threading.CancellationToken) : Threading.Tasks.Task<obj>
property HttpActionContext.ControllerContext: HttpControllerContext
property HttpActionContext.ActionArguments: Collections.Generic.Dictionary<string,obj>
val result : obj
Multiple items
active recognizer Async: Type -> Type option

--------------------
type Async
static member AsBeginEnd : computation:('Arg -> Async<'T>) -> ('Arg * AsyncCallback * obj -> IAsyncResult) * (IAsyncResult -> 'T) * (IAsyncResult -> unit)
static member AwaitEvent : event:IEvent<'Del,'T> * ?cancelAction:(unit -> unit) -> Async<'T> (requires delegate and 'Del :> Delegate)
static member AwaitIAsyncResult : iar:IAsyncResult * ?millisecondsTimeout:int -> Async<bool>
static member AwaitTask : task:Task<'T> -> Async<'T>
static member AwaitWaitHandle : waitHandle:WaitHandle * ?millisecondsTimeout:int -> Async<bool>
static member CancelDefaultToken : unit -> unit
static member Catch : computation:Async<'T> -> Async<Choice<'T,exn>>
static member FromBeginEnd : beginAction:(AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg:'Arg1 * beginAction:('Arg1 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * beginAction:('Arg1 * 'Arg2 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * arg3:'Arg3 * beginAction:('Arg1 * 'Arg2 * 'Arg3 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromContinuations : callback:(('T -> unit) * (exn -> unit) * (OperationCanceledException -> unit) -> unit) -> Async<'T>
static member Ignore : computation:Async<'T> -> Async<unit>
static member OnCancel : interruption:(unit -> unit) -> Async<IDisposable>
static member Parallel : computations:seq<Async<'T>> -> Async<'T []>
static member RunSynchronously : computation:Async<'T> * ?timeout:int * ?cancellationToken:CancellationToken -> 'T
static member Sleep : millisecondsDueTime:int -> Async<unit>
static member Start : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions * ?cancellationToken:CancellationToken -> Task<'T>
static member StartChild : computation:Async<'T> * ?millisecondsTimeout:int -> Async<Async<'T>>
static member StartChildAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions -> Async<Task<'T>>
static member StartImmediate : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartWithContinuations : computation:Async<'T> * continuation:('T -> unit) * exceptionContinuation:(exn -> unit) * cancellationContinuation:(OperationCanceledException -> unit) * ?cancellationToken:CancellationToken -> unit
static member SwitchToContext : syncContext:SynchronizationContext -> Async<unit>
static member SwitchToNewThread : unit -> Async<unit>
static member SwitchToThreadPool : unit -> Async<unit>
static member TryCancelled : computation:Async<'T> * compensation:(OperationCanceledException -> unit) -> Async<'T>
static member CancellationToken : Async<CancellationToken>
static member DefaultCancellationToken : CancellationToken

Full name: Microsoft.FSharp.Control.Async

--------------------
type Async<'T>

Full name: Microsoft.FSharp.Control.Async<_>
static member Async.AwaitTask : task:Threading.Tasks.Task<'T> -> Async<'T>
val value : 'T
val unbox : value:obj -> 'T

Full name: Microsoft.FSharp.Core.Operators.unbox
IActionResultConverter.Convert(controllerContext: HttpControllerContext, actionResult: obj) : HttpResponseMessage
static member Async.StartAsTask : computation:Async<'T> * ?taskCreationOptions:Threading.Tasks.TaskCreationOptions * ?cancellationToken:Threading.CancellationToken -> Threading.Tasks.Task<'T>
val this : AsyncApiActionInvoker
override AsyncApiActionInvoker.InvokeActionAsync : actionContext:HttpActionContext * cancellationToken:Threading.CancellationToken -> Threading.Tasks.Task<HttpResponseMessage>

Full name: Script.AsyncApiActionInvoker.InvokeActionAsync
Multiple items
type ArgumentNullException =
  inherit ArgumentException
  new : unit -> ArgumentNullException + 3 overloads

Full name: System.ArgumentNullException

--------------------
ArgumentNullException() : unit
ArgumentNullException(paramName: string) : unit
ArgumentNullException(message: string, innerException: exn) : unit
ArgumentNullException(paramName: string, message: string) : unit
property HttpActionDescriptor.ReturnType: Type
val resultType : Type
val specialized : MethodInfo
MethodInfo.MakeGenericMethod([<ParamArray>] typeArguments: Type []) : MethodInfo
MethodBase.Invoke(obj: obj, parameters: obj []) : obj
MethodBase.Invoke(obj: obj, invokeAttr: BindingFlags, binder: Binder, parameters: obj [], culture: Globalization.CultureInfo) : obj

More information

Link:http://fssnip.net/pZ
Posted:2 years ago
Author:Ryan Riley
Tags: webapi , aspnet , async