CODEWITHSUNDEEP
c#swaggeropenapinswag
kzfid
kzfid

Reputation: 806

How the Open API controller/service is added?

I am using NSwag to generate the controller code for a c# Open API service

Then, in Program.cs, it is just a simple code from the sample project

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

I can run and test the service, which is fine here.

But what I do not understand is that I do not specify the generated controller class name in the method call of builder.Services.AddControllers() or app.MapControllers().

How does the runtime know which controller it should use, what/where is the magic?

Is it something done by reflection by the underlying framework? I mean to loop all the classes and find those implementing the controller interface?

If this is the case, any reason why it is designed like that, a bit not easy to understand. For grpc or hosted service, we at least need to specify the class (services.AddGrpcClient/services.AddHostedService) to handle it, but why not the open api controller?

Upvotes: 0

Views: 102

Answers (0)

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