TekH
3955ee9f39
Renamed MediatorExtensions to MediatorGetOrContext and GetOrContext<TResponse> to MediatorGetOrContext<TResponse> for consistent naming. Moved the GetOr extension method into the new static class. Updated XML docs and reorganized declarations; no functional changes.
77 lines
3.3 KiB
C#
77 lines
3.3 KiB
C#
using DigitalData.Core.Exceptions;
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using MediatR;
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using System.Collections;
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namespace EnvelopeGenerator.Application.Common.Extensions;
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/// <summary>
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/// Holds a pending MediatR request and exposes <c>Throw…</c> methods that send the request
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/// and throw a chosen exception when the response is <c>null</c> or an empty collection.
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/// </summary>
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/// <typeparam name="TResponse">The expected response type.</typeparam>
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public readonly struct MediatorGetOrContext<TResponse>
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{
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private readonly ISender _sender;
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private readonly IRequest<TResponse?> _request;
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private readonly CancellationToken _cancel;
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internal MediatorGetOrContext(ISender sender, IRequest<TResponse?> request, CancellationToken cancel)
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{
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_sender = sender;
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_request = request;
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_cancel = cancel;
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}
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/// <summary>
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/// Sends the request and throws the exception produced by <paramref name="exceptionFactory"/>
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/// when the response is <c>null</c> or an empty collection.
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/// </summary>
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public async Task<TResponse> Throw(Func<Exception> exceptionFactory)
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{
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if (await _sender.Send(_request, _cancel) is TResponse res)
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{
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// string implements IEnumerable<char>, so "" would be treated as an empty collection without this guard.
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if (res is not string && res is IEnumerable enumerable && !enumerable.Cast<object>().Any())
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throw exceptionFactory();
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return res;
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}
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throw exceptionFactory();
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}
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/// <summary>
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/// Sends the request and throws <see cref="NotFoundException"/> when the response is <c>null</c> or an empty collection.
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/// </summary>
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public Task<TResponse> ThrowNotFound(string? message = null)
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=> Throw(() => new NotFoundException(message ?? $"The requested resource of type {typeof(TResponse).Name} was not found."));
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/// <summary>
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/// Sends the request and throws <see cref="InvalidOperationException"/> when the response is <c>null</c> or an empty collection.
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/// </summary>
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public Task<TResponse> ThrowInvalidOperation(string? message = null)
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=> Throw(() => new InvalidOperationException(message ?? $"The operation for {typeof(TResponse).Name} returned no result."));
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/// <summary>
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/// Sends the request and throws <see cref="BadRequestException"/> when the response is <c>null</c> or an empty collection.
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/// </summary>
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public Task<TResponse> ThrowBadRequest(string? message = null)
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=> Throw(() => new BadRequestException(message ?? $"The request for {typeof(TResponse).Name} is invalid."));
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}
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/// <summary>
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/// Extension methods for <see cref="ISender"/> that provide a fluent API for enforcing non-null responses.
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/// </summary>
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public static class MediatorGetOrContext
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{
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/// <summary>
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/// Begins a fluent chain that sends <paramref name="request"/> and lets you choose how to handle a <c>null</c> or empty response.
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/// <para>Usage:</para>
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/// <code>
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/// await sender.GetOr(query).ThrowNotFound();
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/// await sender.GetOr(query, cancel).Throw(() => new MyException());
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/// </code>
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/// </summary>
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public static MediatorGetOrContext<TResponse> GetOr<TResponse>(this ISender sender, IRequest<TResponse?> request, CancellationToken cancel = default)
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=> new(sender, request, cancel);
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} |