elsa-core/src/common/Elsa.Mediator/Extensions/HandlerExtensions.cs

62 lines
2.9 KiB
C#

using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using Elsa.Mediator.Contracts;
using Elsa.Mediator.Models;
namespace Elsa.Mediator.Extensions;
/// <summary>
/// Contains helper methods for invoking notification handlers.
/// </summary>
public static class HandlerExtensions
{
/// <summary>
/// Gets the handle method for a notification handler of the given notification type.
/// </summary>
/// <param name="notificationType">The notification type.</param>
/// <returns>The handle method.</returns>
public static MethodInfo GetNotificationHandlerMethod(this Type notificationType)
{
var handlerType = typeof(INotificationHandler<>).MakeGenericType(notificationType);
return handlerType.GetMethod("HandleAsync")!;
}
/// <summary>
/// Gets the handle method for a command handler of the given command type.
/// </summary>
/// <param name="commandType">The command type.</param>
/// <returns>The handle method.</returns>
public static MethodInfo GetCommandHandlerMethod([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.Interfaces)] this Type commandType)
{
var commandTypeInterfaces = commandType.GetInterfaces();
var commandTypeInterface = commandTypeInterfaces.FirstOrDefault(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(ICommand<>));
var resultType = commandTypeInterface?.GetGenericArguments()[0] ?? typeof(Unit);
var handlerType = typeof(ICommandHandler<,>).MakeGenericType(commandType, resultType);
return handlerType.GetMethod("HandleAsync")!;
}
/// <summary>
/// Invokes the given handler for the given notification.
/// </summary>
/// <param name="handler">The handler to invoke.</param>
/// <param name="handleMethod">The handle method.</param>
/// <param name="notification">The notification to handle.</param>
/// <param name="cancellationToken">The cancellation token.</param>
public static Task InvokeAsync(this INotificationHandler handler, MethodBase handleMethod, INotification notification, CancellationToken cancellationToken)
{
return (Task)handleMethod.Invoke(handler, new object?[] { notification, cancellationToken })!;
}
/// <summary>
/// Invokes the given handler for the given command.
/// </summary>
/// <param name="handler">The handler to invoke.</param>
/// <param name="handleMethod">The handle method.</param>
/// <param name="command">The command to handle.</param>
/// <param name="cancellationToken">The cancellation token.</param>
public static Task<TResult> InvokeAsync<TResult>(this ICommandHandler handler, MethodBase handleMethod, ICommand command, CancellationToken cancellationToken)
{
var task = (Task<TResult>)handleMethod.Invoke(handler, new object?[] { command, cancellationToken })!;
return task;
}
}