How to handle multiple endpoints in ASP.Net Core 3 Web API properly

Question

I have 2 methods to handle HTTP GET requests, first one for int type input and the other one for string type input.

//GET : api/Fighters/5
[HttpGet("{id}")]
public async Task<ActionResult<Fighter>> GetFighter(int id) 
{
    var fighter = await _context.Fighters.FindAsync(id);

    if (fighter == null) 
    {
        return NotFound();
    }
    return fighter;
}

// GET: api/Fighters/Alex
[Route("api/Fighters/{name}")]
[HttpGet("{name}")]
public async Task<ActionResult<IEnumerable<Fighter>>> GetFighter (string name) 
{
    return await _context.Fighters.Where(f => f.Name == name).ToListAsync();
}

when i send HTTP GET this exception appears (in Postman):

Microsoft.AspNetCore.Routing.Matching.AmbiguousMatchException: The request matched multiple endpoints. Matches: 

FighterGameService.Controllers.FightersController.GetFighter (FighterGameService)
FighterGameService.Controllers.FightersController.GetFighter (FighterGameService)
FighterGameService.Controllers.FightersController.GetFighter (FighterGameService)
FighterGameService.Controllers.FightersController.GetFighter (FighterGameService)
   at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ReportAmbiguity(CandidateState[] candidateState)
   at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ProcessFinalCandidates(HttpContext httpContext, CandidateState[] candidateState)
   at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.Select(HttpContext httpContext, CandidateState[] candidateState)
   at Microsoft.AspNetCore.Routing.Matching.DfaMatcher.MatchAsync(HttpContext httpContext)
   at Microsoft.AspNetCore.Routing.Matching.DataSourceDependentMatcher.MatchAsync(HttpContext httpContext)
   at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

GET api/fighters/1 would cause error obviously since "1" could be either int or string so i solved my problem by combining two methods:

// GET: api/Fighters/5
// GET: api/Fighters/Alex
[HttpGet("{idOrName}")]
public async Task<ActionResult<IEnumerable<Fighter>>> GetFighter(string idOrName)
{
    if (Int32.TryParse(idOrName, out int id))
    {
        return await _context.Fighters.Where(f => f.Id == id).ToListAsync();
    }
    else
    {
        return await _context.Fighters.Where(f => f.Name == idOrName).ToListAsync();
    }

}

this works however this doesn't feel right at all. What is the proper way to handle this problem?

Answer 1

You can use route constraint

[HttpGet("{id:int}")]
public async Task<ActionResult<Fighter>> GetFighter(int id) 

[HttpGet("{name}")]
public async Task<ActionResult<IEnumerable<Fighter>>> GetFighter (string name)