Actions require unique method/path combination for Swagger

Question

I have 2 HTTP GET method in same controller and give me this error

HTTP method "GET" & path "api/DataStore" overloaded by actions - DPK.HostApi.Controllers.DataStoreController.GetByIdAsync (DPK.HostApi),DPK.HostApi.Controllers.DataStoreController.GetAllAsync (DPK.HostApi). Actions require unique method/path combination for Swagger 2.0.

My Controller :

[Route("api/[controller]")]
[ApiController]
public class DataStoreController : ApiControllerBase
{
    private readonly IDataStoreService _dataStoreService;

    public DataStoreController(IDataStoreService dataStoreService)
    {
        _dataStoreService = dataStoreService;
    }


    [HttpPost]
    public async Task<IActionResult> PostAsync([FromBody] DataStoreCommand dataStoreCommand)
    {
        try
        {
            if (ModelState.IsValid)
            {
                await _dataStoreService.PostAsync(dataStoreCommand);
                return Ok();
            }

            var errorList = ModelState.Values.SelectMany(m => m.Errors).Select(e => e.ErrorMessage).ToList();
            return ValidationProblem();
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }


    [HttpPut]
    public async Task<IActionResult> PutAsync([FromBody] DataStoreCommand dataStoreCommand)
    {
        try
        {
            if (ModelState.IsValid)
            {
                await _dataStoreService.PutAsync(dataStoreCommand);
                return Ok();
            }

            var errorList = ModelState.Values.SelectMany(m => m.Errors).Select(e => e.ErrorMessage).ToList();
            return ValidationProblem();
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }


    [HttpDelete]
    public async Task<IActionResult> DeleteAsync(int id)
    {
        try
        {
            if (ModelState.IsValid)
            {
                var item = await _dataStoreService.GetByIdAsync(id);
                await _dataStoreService.DeleteAsync(item);
                return Ok();
            }

            var errorList = ModelState.Values.SelectMany(m => m.Errors).Select(e => e.ErrorMessage).ToList();
            return ValidationProblem();
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }


    [HttpGet]
    public async Task<DataStoreQuery> GetByIdAsync(int id)
    {
        try
        {
            return await _dataStoreService.GetByIdAsync(id);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }





    [HttpGet]
    public async Task<IEnumerable<DataStoreQuery>> GetAllAsync(string instanceName, string dbname, string userName, string userPass, bool isActive, DateTime? startCreatedDate, DateTime? endCreatedDate, DateTime? startModifiedDate, DateTime? endModifiedDate)
    {
        object[] parameters = { instanceName, dbname, userName, userPass, isActive, startCreatedDate, endCreatedDate, startModifiedDate,  endModifiedDate};
        var parameterName = "@instanceName , @dbname , @userName , @userPass , @isActive , @startCreatedDate , @endCreatedDate , @startModifiedDate , @endModifiedDate";
        try
        {
            return await _dataStoreService.ExecWithStoreProcedure(parameterName, parameters);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }




}

My Startup :

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v1", new Info
            {
                Version = "v1",
                Title = " ",
                Description = " ",
                TermsOfService = "None",
                Contact = new Contact() { Name = " ", Email = " ", Url = " " }
            });
        });
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseMvc();


        app.UseSwagger();
        app.UseSwaggerUI(c =>
        {
            c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
        });
    }
}

Answer 1

I changed the controller route to following:

[Route("api/[controller]/[action]")]

or you can also define explicit route for action as well:

[Route("GetById")]

Answer 2

You can resolve it as follows:

services.AddSwaggerGen (c =>
  {
    other configs;
    c.ResolveConflictingActions (apiDescriptions => apiDescriptions.First ());
  });
//in the Startup.cs class in the ConfigureServices method

or you can put routes to differentiate your methods, for example:

[HttpGet("~/getsomething")]
[HttpGet("~/getothersomething")]

Answer 3

you need to map id into HttpGet.

[HttpGet("{id}")]
public async Task<DataStoreQuery> GetByIdAsync(int id)
{
    try
    {
        return await _dataStoreService.GetByIdAsync(id);
    }
    catch (Exception e)
    {
        Console.WriteLine(e);
        throw;
    }
}

when you specify HttpGet by not providing template, Swashbuckle tries to use default map for both of them. hence conflict occurs.

Answer 4

You can also merge methods with same endpoints to one with optional parameters. Example of implementation tested in net core 5 project:

services.AddSwaggerGen(c => 
{
    c.ResolveConflictingActions(apiDescriptions =>
    {
        var descriptions = apiDescriptions as ApiDescription[] ?? apiDescriptions.ToArray();
        var first = descriptions.First(); // build relative to the 1st method
        var parameters = descriptions.SelectMany(d => d.ParameterDescriptions).ToList();

        first.ParameterDescriptions.Clear();
        // add parameters and make them optional
        foreach (var parameter in parameters)
            if (first.ParameterDescriptions.All(x => x.Name != parameter.Name))
            {
                first.ParameterDescriptions.Add(new ApiParameterDescription
                {
                    ModelMetadata = parameter.ModelMetadata,
                    Name = parameter.Name,
                    ParameterDescriptor = parameter.ParameterDescriptor,
                    Source = parameter.Source,
                    IsRequired = false,
                    DefaultValue = null
                });
            }
        return first;
    });
});

Answer 5

If the method name are same then change the request method with parameter. I changed the request method to following :

[HttpGet]
    public string products()
    {
        // add other code
        // ex. (return "products()";)
    }


[HttpGet("{id}")]
    public string products(int id)
    {
        // add other code
        // ex. (return "products(int id)";)
    }

Answer 6

If method has "Name" in it, then also it throws this error. To fix it,

Change from

[HttpGet(Name = "GetWeatherForecast")]
[HttpGet(Name = "GetWeatherForecastById")]

To

[HttpGet("GetWeatherForecast")]
[HttpGet("GetWeatherForecastById")]

Answer 7

This is how I specified the unique routes for method name

[HttpGet("~/GetWeatherForecast")]

Keeping it above the methods

[HttpGet("~/GetWeatherForecast")]
public int Get()
{
   return Random.Next(5)
}

[HttpPost("~/InsertAddition")]
public int InsertAddition(int num1, int num2)
{
  return num1 + num2;
}

Answer 8

Try adding both Route and HttpGet.

    [HttpGet]
    [Route(~/GetByIdAsync/{id})]
    public async Task<DataStoreQuery> GetByIdAsync(int id)

    [HttpGet]
    [Route(~/GetAllAsync)]
    public async Task<IEnumerable<DataStoreQuery>> GetAllAsync(string instanceName, string dbname, string userName, string userPass, bool isActive, DateTime? startCreatedDate, DateTime? endCreatedDate, DateTime? startModifiedDate, DateTime? endModifiedDate)