Louis Seubert
f77c1ff29b
Introduce compile-time registration capabilities with source generation, enabling automatic handler registration.
94 lines
3.1 KiB
Markdown
94 lines
3.1 KiB
Markdown
# `Geekeey.Request`
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Simple mediator implementation in .NET with minimal dependencies.
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## Features
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- **Simple interfaces:** no complex constraints, just marker interfaces that work.
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- **Minmal dependencies:** only depends on `Microsoft.Extensions.DependencyInjection.Abstractions` and the
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`Microsoft.Extensions.Options` package.
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## Getting Started
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### Install the NuGet package:
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```shell
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dotnet add package Geekeey.Request
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```
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You may need to add our NuGet feed to your `nuget.config` this can be done by running the following command:
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```shell
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dotnet nuget add source -n geekeey https://code.geekeey.de/api/packages/geekeey/nuget/index.json
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```
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### Usage
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```csharp
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public static Task<int> Main()
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{
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var collection = new ServiceCollection();
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collection.AddRequestDispatcher(builder => builder
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.SearchHandlerInAssembly(typeof(ScalarHandler).Assembly)
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.Add(typeof(ScalarBehavior)));
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await using var provider = collection.BuildServiceProvider();
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var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
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var request = new ScalarRequest { Value = "Hello" };
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var result = await dispatcher.DispatchAsync(request);
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Console.WriteLine(result);
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return 0;
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}
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public class ScalarRequest : IScalarRequest<string>
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{
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public string Value { get; set; } = string.Empty;
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}
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public class ScalarHandler : IScalarRequestHandler<ScalarRequest, string>
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{
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public Task<string> HandleAsync(ScalarRequest request, CancellationToken cancellationToken)
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{
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return Task.FromResult($"{request.Value} World");
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}
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}
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public class ScalarBehavior : IScalarRequestBehavior<ScalarRequest, string>
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{
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public async Task<string> HandleAsync(ScalarRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
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{
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Console.WriteLine("Before");
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var result = await next(request, cancellationToken);
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Console.WriteLine("After");
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return result;
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}
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}
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```
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### Compile-time registration
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Projects that directly reference `Geekeey.Request` also get generated registration methods in the
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`Geekeey.Request` namespace:
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```csharp
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collection.AddRequestDispatcher(builder => builder
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.AddExampleProject()
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.Add(typeof(ScalarBehavior)));
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collection.AddRequestDispatcher(builder => builder
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.AddExampleProject(ServiceLifetime.Scoped)
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.Add(typeof(ScalarBehavior)));
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```
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- generation is enabled by default
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- disable it with `<CompiletimeRequestDispatchHandlerRegistration>false</CompiletimeRequestDispatchHandlerRegistration>`
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- rename the generated `Add<Name>(...)` methods with `CompiletimeRequestDispatchHandlerName`
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- only request handlers are generated; behaviors still need normal registration
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- nested request handlers are rejected during `Add(...)` registration, including `SearchHandlerInAssembly(...)` and by the source generator
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- use one registration style per assembly: generated methods or `SearchHandlerInAssembly(...)`
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## Behaviour of the Handlers
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Handlers are resolved from either the DI container or are created on the fly but can receive arguments from the DI
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container when being constructed. The same also applied for the request pipeline behaviours.
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