38 lines
1.7 KiB
C#
38 lines
1.7 KiB
C#
using MediatR;
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using ZeroFramework.DeviceCenter.Infrastructure.Idempotency;
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namespace ZeroFramework.DeviceCenter.Application.Infrastructure
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{
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/// <summary>
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/// Provides a base implementation for handling duplicate request and ensuring idempotent updates, in the cases where
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/// a requestid sent by client is used to detect duplicate requests.
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/// </summary>
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public class IdentifiedCommandHandler<TRequest, TResponse>(IMediator mediator, IRequestManager requestManager) : IRequestHandler<IdentifiedCommand<TRequest, TResponse>, TResponse> where TRequest : IRequest<TResponse>
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{
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private readonly IMediator _mediator = mediator;
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private readonly IRequestManager _requestManager = requestManager;
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/// <summary>
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/// Creates the result value to return if a previous request was found
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/// </summary>
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protected virtual TResponse? CreateResultForDuplicateRequest() => default;
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/// <summary>
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/// This method handles the command. It just ensures that no other request exists with the same ID, and if this is the case
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/// just enqueues the original inner command.
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/// </summary>
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public async Task<TResponse> Handle(IdentifiedCommand<TRequest, TResponse> command, CancellationToken cancellationToken)
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{
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if (await _requestManager.ExistAsync(command.Id))
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{
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return CreateResultForDuplicateRequest() ?? throw new NotImplementedException();
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}
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await _requestManager.CreateRequestForCommandAsync<TRequest>(command.Id);
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// Send the embeded business command to mediator so it runs its related CommandHandler
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return await _mediator.Send(command.Command, cancellationToken);
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}
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}
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} |