C#•2y ago

✅ Not able to locate web api controllers in a class library

Hello, I'm having some issues with trying to load web api controllers from a class library. I did try explicitly adding the assembly with AddControllers().AddApplicationPart, but no luck there. I'm thinking it has to do with the pattern I'm using for registering services in separate assemblies.

32 Replies

El Grande Padre•2y ago

This is what my main project startup looks like:

namespace Core
{
    public class Startup
    {
        private readonly IConfiguration _config;

        public Startup(IConfiguration config)
        {
            _config = config;
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddApiServices(_config);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app)
        {
            app.ConfigureApi(_config);
        }
    }
}

namespace Core
{
    public class Startup
    {
        private readonly IConfiguration _config;

        public Startup(IConfiguration config)
        {
            _config = config;
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddApiServices(_config);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app)
        {
            app.ConfigureApi(_config);
        }
    }
}

This is the extension pattern I'm using to piggy back off the startup of the main project inside of the class library

namespace Api.Extensions
{
    public static class ApiStartupExt
    {
        public static void AddApiServices(this IServiceCollection builder, IConfiguration config)
        {
        builder.AddControllers().AddApplicationPart(typeof(ApiStartupExt).Assembly);
            builder.AddSwaggerGen(c => c.SwaggerDoc("v0", new OpenApiInfo
            {
                Title = "test_service",
                Version = "v0"
            }));
        }
        public static void ConfigureApi(this IApplicationBuilder app, IConfiguration config)
        {
            if (!config["Environment"]!.Equals("Production"))
            {
                app.UseSwagger();
                app.UseSwaggerUI(c =>
                {
                    c.SwaggerEndpoint("/swagger/v1/swagger.json", "test_service v0");
                    c.RoutePrefix = string.Empty;
                });
            }

            // Map rest services to port 43000
            // In my actual application I also have GRPC endpoints on the same host
            // so I need to use the UseWhen method to avoid some issues there
            app.UseWhen(context => context.Connection.LocalPort == config.GetValue<int>("Rest:Port"),
              builder =>
              {
                  builder.UsePathBase(new PathString("/api"));
                  builder.UseRouting();
                  builder.UseEndpoints(endpoints => endpoints.MapControllers());
              }
            );
        }
    }
}

namespace Api.Extensions
{
    public static class ApiStartupExt
    {
        public static void AddApiServices(this IServiceCollection builder, IConfiguration config)
        {
        builder.AddControllers().AddApplicationPart(typeof(ApiStartupExt).Assembly);
            builder.AddSwaggerGen(c => c.SwaggerDoc("v0", new OpenApiInfo
            {
                Title = "test_service",
                Version = "v0"
            }));
        }
        public static void ConfigureApi(this IApplicationBuilder app, IConfiguration config)
        {
            if (!config["Environment"]!.Equals("Production"))
            {
                app.UseSwagger();
                app.UseSwaggerUI(c =>
                {
                    c.SwaggerEndpoint("/swagger/v1/swagger.json", "test_service v0");
                    c.RoutePrefix = string.Empty;
                });
            }

            // Map rest services to port 43000
            // In my actual application I also have GRPC endpoints on the same host
            // so I need to use the UseWhen method to avoid some issues there
            app.UseWhen(context => context.Connection.LocalPort == config.GetValue<int>("Rest:Port"),
              builder =>
              {
                  builder.UsePathBase(new PathString("/api"));
                  builder.UseRouting();
                  builder.UseEndpoints(endpoints => endpoints.MapControllers());
              }
            );
        }
    }
}

Here's the output I get when making a request:

info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:43000/api/WeatherForecast - 0
dbug: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[0]
      Wildcard detected, all requests with hosts will be allowed.
dbug: Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware[1]
      POST requests are not supported
dbug: Microsoft.AspNetCore.Server.Kestrel.Connections[9]
      Connection id "0HMNNSN1PNNGU" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://localhost:43000/api/WeatherForecast - 0 - 404 0 - 11.6784ms

info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:43000/api/WeatherForecast - 0
dbug: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[0]
      Wildcard detected, all requests with hosts will be allowed.
dbug: Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware[1]
      POST requests are not supported
dbug: Microsoft.AspNetCore.Server.Kestrel.Connections[9]
      Connection id "0HMNNSN1PNNGU" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://localhost:43000/api/WeatherForecast - 0 - 404 0 - 11.6784ms

minimal reproduction repo if anyone takes a look: https://github.com/RyanCallahan312/multiple-projects-with-web-api-controllers

Unknown User•2y ago

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El Grande Padre•2y ago

I understand the issues with magic string constants, but I don't think thats relevant to the question. The repo this issue is actually happening uses options configs. I just didn't want to copy over all the configuration

Unknown User•2y ago

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El Grande Padre•2y ago

unless im completely misunderstanding and thats preventing controllers from being discovered

Unknown User•2y ago

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El Grande Padre•2y ago

thats why i included the repo because i realized it was too much for just copy and pasting files

Unknown User•2y ago

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El Grande Padre•2y ago

its in the same assembly as the extention

Unknown User•2y ago

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El Grande Padre•2y ago

No i did not. what does ... do?

Unknown User•2y ago

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El Grande Padre•2y ago

oh then yes I did specify the controller class same result and same assembly

Unknown User•2y ago

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El Grande Padre•2y ago

i think i accidentally added that when adding <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />

Unknown User•2y ago

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El Grande Padre•2y ago

yep thats pretty much what I have in the private repo.

Unknown User•2y ago

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El Grande Padre•2y ago

The motivating factor for me right now is transitioning away from a ruby world that has bit me in the ass with convoluted "god objects" or "god models" too many times

Unknown User•2y ago

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MODiX•2y ago

appsettings.json:

{
  "My": {
    "Foo": {
      "Kix": 5
    }
  }
}

{
  "My": {
    "Foo": {
      "Kix": 5
    }
  }
}

src/Foo/FooOptions.cs:

public class FooOptions
{
  public const string SectionName = "My:Foo";

  public string Bar {get;set;} = "default value for bar";
  public int Kix {get;set;} = -1;
  public DateTime? Pouet {get;set;} = default;
}

public class FooOptions
{
  public const string SectionName = "My:Foo";

  public string Bar {get;set;} = "default value for bar";
  public int Kix {get;set;} = -1;
  public DateTime? Pouet {get;set;} = default;
}

src/Foo/FooServiceCollectionExtensions.cs:

namespace Microsoft.Extensions.DependencyInjection; // <==== recommanded for service.Add so that you don't clutter Startup file

public class FooServiceCollectionExtensions
{
  public static IServiceCollection AddFoo(this IServiceCollection services) =>
    services
      .AddOptions<FooOptions>()
      .BindConfiguration(FooOptions.SectionName)
      .Validate(options => options.Kix >= 0, $"The configuration key '{FooOptions.SectionName}:{nameof(Kix)}' cannot be negative")
      ;

  public static IServiceCollection AddFoo(this IServiceCollection services, Action<FooOptions> configure) =>
    services
      .AddFoo()
      .Configure(configure);

namespace Microsoft.Extensions.DependencyInjection; // <==== recommanded for service.Add so that you don't clutter Startup file

public class FooServiceCollectionExtensions
{
  public static IServiceCollection AddFoo(this IServiceCollection services) =>
    services
      .AddOptions<FooOptions>()
      .BindConfiguration(FooOptions.SectionName)
      .Validate(options => options.Kix >= 0, $"The configuration key '{FooOptions.SectionName}:{nameof(Kix)}' cannot be negative")
      ;

  public static IServiceCollection AddFoo(this IServiceCollection services, Action<FooOptions> configure) =>
    services
      .AddFoo()
      .Configure(configure);

Program.cs / Startup.cs:

services.AddFoo();
// or
services.AddFoo(fooOptions => fooOptions.Kix = 12);

services.AddFoo();
// or
services.AddFoo(fooOptions => fooOptions.Kix = 12);

Bar.cs:

public class Bar
{
  private readonly FooOptions _fooOptions;

  // .Value in ctor is fine only if it's always ever a non-changing value (no reload and/or no scoped resolution)
  public Bar(IOptions<FooOptions> fooOptions)
    => _fooOptions = fooOptions.Value;
}

public class Bar
{
  private readonly FooOptions _fooOptions;

  // .Value in ctor is fine only if it's always ever a non-changing value (no reload and/or no scoped resolution)
  public Bar(IOptions<FooOptions> fooOptions)
    => _fooOptions = fooOptions.Value;
}

Unknown User•2y ago

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El Grande Padre•2y ago

I updated the project but still same behavior. Still a bit new to anything outside of basic one project crud apps so how would FrameworkReference not being defined break things?

Unknown User•2y ago

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MODiX•2y ago

tebeco#0205

<FrameworkReference Include="Microsoft.AspNetCore.App" />

Quoted by

<@!689473681302224947> from #Which dll do I need to load for Microsoft.AspNetCore.Builder WebApplication Class to be loaded? (click here)

React with ❌ to remove this embed.

Unknown User•2y ago

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El Grande Padre•2y ago

Adding the framework reference didn't fix it. I'm trying to find a way to list out all registered controllers to see for sure they're not registered

Unknown User•2y ago

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El Grande Padre•2y ago

Unknown User•2y ago

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MODiX•2y ago

tebeco#0205

TLDR: if you open a term and dotnet new webapi -n PleaseDeleteMeLater you'll have an example to re-use and delete later

Quoted by

<@!689473681302224947> from #Not able to locate web api controllers in a class library (click here)

React with ❌ to remove this embed.

El Grande Padre•2y ago

so that worked... I added a project reference to the LibApi and it found the controller without going into the extension method Solved. I think it was <FrameworkReference Include="Microsoft.AspNetCore.App" /> but the secondary issue of me not including the rest port in the appsettings.json didn't show it working once that was fixed. Guess thats what I get for laziness and not copying over the option configs. ty @TeBeConsulting

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✅ Not able to locate web api controllers in a class library