107 lines
4.0 KiB
C#
107 lines
4.0 KiB
C#
using System;
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using System.Reflection;
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using System.Threading.Tasks;
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using Tapeti.Annotations;
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using Tapeti.Config;
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using Tapeti.Flow.Annotations;
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using Tapeti.Helpers;
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namespace Tapeti.Flow.Default
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{
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internal class FlowBindingMiddleware : IControllerBindingMiddleware
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{
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public void Handle(IControllerBindingContext context, Action next)
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{
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if (context.Method.GetCustomAttribute<StartAttribute>() != null)
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return;
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if (context.Method.GetCustomAttribute<ContinuationAttribute>() != null)
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context.SetBindingTargetMode(BindingTargetMode.Direct);
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RegisterYieldPointResult(context);
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RegisterContinuationFilter(context);
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next();
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ValidateRequestResponse(context);
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}
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private static void RegisterContinuationFilter(IControllerBindingContext context)
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{
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var continuationAttribute = context.Method.GetCustomAttribute<ContinuationAttribute>();
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if (continuationAttribute == null)
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return;
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context.Use(new FlowMiddleware());
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if (context.Result.HasHandler)
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return;
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// Continuation without IYieldPoint indicates a ParallelRequestBuilder response handler,
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// make sure to store it's state as well
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if (context.Result.Info.ParameterType == typeof(Task))
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{
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context.Result.SetHandler(async (messageContext, value) =>
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{
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await (Task)value;
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await HandleParallelResponse(messageContext);
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});
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}
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else if (context.Result.Info.ParameterType == typeof(void))
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{
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context.Result.SetHandler((messageContext, value) => HandleParallelResponse(messageContext));
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}
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else
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throw new ArgumentException($"Result type must be IYieldPoint, Task or void in controller {context. Method.DeclaringType?.FullName}, method {context.Method.Name}");
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}
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private static void RegisterYieldPointResult(IControllerBindingContext context)
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{
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if (!context.Result.Info.ParameterType.IsTypeOrTaskOf(typeof(IYieldPoint), out var isTaskOf))
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return;
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if (isTaskOf)
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{
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context.Result.SetHandler(async (messageContext, value) =>
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{
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var yieldPoint = await (Task<IYieldPoint>)value;
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if (yieldPoint != null)
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await HandleYieldPoint(messageContext, yieldPoint);
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});
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}
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else
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context.Result.SetHandler((messageContext, value) => HandleYieldPoint(messageContext, (IYieldPoint)value));
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}
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private static Task HandleYieldPoint(IControllerMessageContext context, IYieldPoint yieldPoint)
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{
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var flowHandler = context.Config.DependencyResolver.Resolve<IFlowHandler>();
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return flowHandler.Execute(context, yieldPoint);
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}
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private static Task HandleParallelResponse(IControllerMessageContext context)
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{
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var flowHandler = context.Config.DependencyResolver.Resolve<IFlowHandler>();
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return flowHandler.Execute(context, new DelegateYieldPoint(async flowContext =>
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{
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await flowContext.Store();
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}));
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}
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private static void ValidateRequestResponse(IControllerBindingContext context)
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{
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var request = context.MessageClass?.GetCustomAttribute<RequestAttribute>();
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if (request?.Response == null)
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return;
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if (!context.Result.Info.ParameterType.IsTypeOrTaskOf(t => t == request.Response || t == typeof(IYieldPoint), out _))
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throw new ResponseExpectedException($"Response of class {request.Response.FullName} expected in controller {context.Method.DeclaringType?.FullName}, method {context.Method.Name}");
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}
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}
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}
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