Use custom exception for missing beatmaps

Author: Syriiin

Difficalcy/Controllers/CalculatorController.cs

@@ -33,7 +33,14 @@ public ActionResult<CalculatorInfo> GetInfo()
         [HttpGet("calculation")]
         public async Task<ActionResult<TCalculation>> GetCalculation([FromQuery] TScore score)
         {
-            return Ok(await calculatorService.GetCalculation(score));
+            try
+            {
+                return Ok(await calculatorService.GetCalculation(score));
+            }
+            catch (BeatmapNotFoundException e)
+            {
+                return BadRequest(new { error = e.Message });
+            }
         }
 
         /// <summary>
@@ -43,7 +50,14 @@ public async Task<ActionResult<TCalculation>> GetCalculation([FromQuery] TScore
         [Consumes("application/json")]
         public async Task<ActionResult<TCalculation[]>> GetCalculationBatch([FromBody] TScore[] scores)
         {
-            return Ok(await Task.WhenAll(scores.Select(score => calculatorService.GetCalculation(score))));
+            try
+            {
+                return Ok(await Task.WhenAll(scores.Select(calculatorService.GetCalculation)));
+            }
+            catch (BeatmapNotFoundException e)
+            {
+                return BadRequest(new { error = e.Message });
+            }
         }
     }
 }

Difficalcy/Services/BeatmapNotFoundException.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace Difficalcy.Services
+{
+    public class BeatmapNotFoundException(string beatmapId) : Exception($"Beatmap {beatmapId} not found")
+    {
+    }
+}

Difficalcy/Services/TestBeatmapProvider.cs

@@ -1,8 +1,6 @@
-using System;
 using System.IO;
 using System.Reflection;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Http;
 
 namespace Difficalcy.Services
 {
@@ -11,7 +9,7 @@ public class TestBeatmapProvider(string resourceAssemblyName) : IBeatmapProvider
         public Task EnsureBeatmap(string beatmapId)
         {
             var resourceName = GetResourceName(beatmapId);
-            _ = ResourceAssembly.GetManifestResourceInfo(resourceName) ?? throw new BadHttpRequestException($"Beatmap not found: {beatmapId}");
+            _ = ResourceAssembly.GetManifestResourceInfo(resourceName) ?? throw new BeatmapNotFoundException(beatmapId);
             return Task.CompletedTask;
         }
 

Difficalcy/Services/WebBeatmapProvider.cs

@@ -1,7 +1,6 @@
 using System.IO;
 using System.Net.Http;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Configuration;
 
 namespace Difficalcy.Services
@@ -18,16 +17,20 @@ public async Task EnsureBeatmap(string beatmapId)
             if (!File.Exists(beatmapPath))
             {
                 if (_downloadMissingBeatmaps != "true")
-                    throw new BadHttpRequestException("Beatmap not found");
+                    throw new BeatmapNotFoundException(beatmapId);
 
                 using var response = await _httpClient.GetAsync($"https://osu.ppy.sh/osu/{beatmapId}");
                 if (!response.IsSuccessStatusCode || response.Content.Headers.ContentLength == 0)
-                    throw new BadHttpRequestException("Beatmap not found");
+                    throw new BeatmapNotFoundException(beatmapId);
 
                 using var fs = new FileStream(beatmapPath, FileMode.CreateNew);
                 await response.Content.CopyToAsync(fs);
                 if (fs.Length == 0)
-                    throw new BadHttpRequestException("Beatmap not found");
+                {
+                    fs.Close();
+                    File.Delete(beatmapPath);
+                    throw new BeatmapNotFoundException(beatmapId);
+                }
             }
         }